PinoyDVD: The Pinoy Digital Video & Devices Community
Home Theater => Audio => Amplifier => Topic started by: joan2 on Jul 24, 2003 at 05:41 PM
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for those with no budget for tube amps but whould like to try their hands at soldering, then this may be for you:http://www.diyaudio.com/forums/forumdisplay.php?s=&forumid=40 (http://www.diyaudio.com/forums/forumdisplay.php?s=&forumid=40)
http://www.diyaudio.com/forums/forumdisplay.php?s=&forumid=40 (http://www.diyaudio.com/forums/forumdisplay.php?s=&forumid=40)
these amps are based on national semiconductor single chip power amps, the LM3875,LM3886 and its cousins.
the adavantage of these amps is simplicity, no need to use pcb as point to point wiring can be done....the chip is available thru rs electronincs phils as an order item and cost around 450 per chip for the LM3886, thus for a budget of around 5000 pesos, you can have a 200watt stereo amp....
i can guide anyone wishing to biuld these amps thru my [email protected]
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the toroidal transformer for this project is P2,000 each already from Farnell or RS Components.
since you meantioned P5,000 pesos for stereo, i assume you have another source. will you share that?
i know somebody who assembled an aksa amplifier and used a pair of these toroids.
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hmnnn interesting...sir joan2 you got mail! ;D I checked the link...what can you say about the gainclone design using tubes? thanks!
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power transformer need not be torroid type an EI core would do....at a low cost compared to torroids which had to be imported....this is available from alexan, same as with metal film resistors...if you need more power such as when you are paralelling chips and/or brdging them, then go for a bigger va capacity, i can help you with the design for that...these amps are not level gain stage types and as such can use an EI core type, i have worked on many amps with an EI core as well as a torroid, sonnically to me they are the same....consider these:
http://www.soundstage.com/maxdb/maxdb071998.htm (http://www.soundstage.com/maxdb/maxdb071998.htm)
http://www.diyaudio.com/forums/showthread.php?s=&threadid=16337 (http://www.diyaudio.com/forums/showthread.php?s=&threadid=16337)
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joan2, exactly what i want to hear! dumping the toroid in favor of EI makes a lot of sense and will bring you to sub 5K or even less. ;D
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I have a toroidal transformer, PM me if you want.
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check this out
http://members.ozemail.com.au/~joeras/index.html
seems like good value for the money. could this be the middle ground in the great tube / ss shootout?
sir tony, sent you mail. thanks.
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USD1,200 ::)
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sir arnoldc, i meant that it might be feasible for a diy project... ;)
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sorry. by all means it could be.
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for those bent on doing one, here is where you can buy the ic LM3886:
http://ph.rs-c.dk/toc/produkt-tocframes.html (http://ph.rs-c.dk/toc/produkt-tocframes.html)
the metal film resistors can be purchased from alexan, the capacitors from deeco, choose the name brands, like rubycon or elna, or nichicon....
the power transformer can be purchased from alexan, it's the one they used for a 40 watt per channel amp. shoudln't cost that much, u can use one transformer per channel so you can have more room for expansion later on...
the chasis can be made out of ga.13 aluminum and can serve as heatsink also.....i purchase my aluminums from sulimco metals in binondo area, aranque market.. lots of sheet metal shops that can do bending for you....
i still thinks this project can be built on a 5k budget...
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for those bent on doing one, here is where you can buy the ic LM3886:
http://ph.rs-c.dk/toc/produkt-tocframes.html (http://ph.rs-c.dk/toc/produkt-tocframes.html)
the chasis can be made out of ga.13 aluminum and can serve as heatsink also.....i purchase my aluminums from sulimco metals in binondo area, aranque market.. lots of sheet metal shops that can do bending for you....
i still thinks this project can be built on a 5k budget...
a slight bit of digression, do you have sulimco metal shop contact info... can these guys create customized 19" slim-type cabinets similar to the photo below but for other purpose?
(http://www.phonic.com/product/signalpc/pro_sipro_ppc1200.jpg)
please kindly pm me back.
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sulimco metals sells cut to size sheet metal plates, in copper, aluminum or brass, you have to take it to nearby metal shops for bending and forming, i used to buy cut to size 1/4 in alum metal plates and have a mchine shop finish it for me as front panel facia....i used to have them make one cabinet just like yours which i use for electronic active crossover network.....fyi i made all my amplifier cabinets from ga14 aluminum sheets with a ga16. aluminum sheets as covers....
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i have been going around looking at prices of parts so here is a partial breakdown:\
1. 2pcs LM3886 @460 each
2. 500va power transformer @ 600
3. filter caps at 200
so partial amount is 1720 for above three major parts, this project can still be had for about 5,000...
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Hi Joan,
Just want to know if by experience you know that LM3886 is better than either LM3875 or LM1875. I noticed kasi that the latter 2 are the most commonly mentioned chips for first time gainclone DIYers. I can look at the datasheet but I'm not sure I'd know what to look for.
Where can you get that 500VA transformers? I'm tempted to try after reading the review on the AMP-1 at 6 moons and considering its really cheap--I reckon that even with toroids (2K for 225 VA) and quality capacitors (Panasonic FC 2200 35v) and Welwyn resistors (RC55 series), Hexfreds (MUR860), the cost is just about 6-7K. LM3875 goes for a little over 400 apiece at Farnell and LM1875 is almost half of that.
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garp.
truth to tell. i haven't built one yet, but i have lots of experience with leach super amps, and other bipolar transistor amps..from what i know so far the lm3886 has muting and the lm3875 has none, this is no problem really...the selling point of gainclones is that of simplicity, even a newbie can do with point to point wiring..see the work of peter daniels at diyaudio....i have 5 lm3875 chips coming in from hongkong and i intend to build a subwoofer.satellite speaker system with those chips, the sub will be powered by a bridge iteration and the satellite on normal single chips, so this will give my pc an honest to goodness 200watt power amps, i have an electronics crossover to be integrated with the gainclone amps....i may even use a tube buffer for inputs....the 500va transformer is my own design using locally available materials, i overated it for future expansion needs, as gainclone is easily scalable....
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here are links you might find usefull:
http://www.decdun.fsnet.co.uk/gaincloneFAQ.html (http://www.decdun.fsnet.co.uk/gaincloneFAQ.html)
http://www.decdun.fsnet.co.uk/gainclonesl.html
(http://www.decdun.fsnet.co.uk/gainclonesl.html)
national semicon has a free samples program wherein they give away up to 5pcs of these chips, unfortunately, they can not service the philippines at the moment, so if you have friends and relatives in other parts of asia, then you can avail of this, this is how i am getting my gainclone chips....
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sir joan2, thanks a lot for the very fast reply (and the attachment you sent) last friday.
anyway, i was poring over the document and i was just wondering that the three projects (bridged, parallel and bridged/parallel) might be a tad difficult for my skill level.
i was just curious; except when built as monoblocks, are gainclones supposed to be built as integrated amps? i've been going over the threads at diyaudio and i came across this...
http://www.diyaudio.com/forums/showthread.php?s=&threadid=17556&highlight=legit (http://www.diyaudio.com/forums/showthread.php?s=&threadid=17556&highlight=legit)
comments or suggestions would be most welcome. thanks a lot...
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ramble_on,
regarding that article, it shows how easy it is to buid that amp, even as a newbie....don't worry much about the offsets...a +/-100mv is acceptable...a big offset will cause noticeable cone displacement at idle....
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Joan2 thanks for the reply. May I know what schematic you're using? I've seen the one at http://www.decdun.fsnet.co.uk/ and he seems to be following Peter Daniel's circuit. There's another one at Chip AMP DIY which I think is Thorsten's and this is the one I think i'll use. Can you also point me to the schematic for the bridged or parallel amps? Thanks.
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garp, sent you pm.
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garp, pmd you.
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Replied to your PM.
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i favor the inverted clone type, to me it's simpler, you can use many values for the input and feedback resistors as long as the ratio is about 19 to 22, lower values of input resistor means lower noise, but if using an input capacitor, means higher low freq. cutoff, meaning you will have to use a bigger size input cap. the application notes i gave ramble_on should fill you in on any information you require...fyi i have many stock of 0.1ohm 2 watt resistor which can be used for output ballast resistor in case you want to do a parralel,bridge iteration of this amp...btw, the lm3875is aboult half the price of the lm3886...
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I'll be constructing a 20 watt "gainclone" using a pair of lm1875's (I have four chips at hand). if anyone can help me in adding a tube buffer input stage I would gladly appreciate it ;D
here is the schematic: http://sound.westhost.com/project72.htm
I'm a total newbie but if i'll be given a schematic then I can follow somewhat with the circuit. thanks!
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i'm also planning of putting one together. i've got almost everything in place and my chips are due in two weeks time (a pair of lm3875's).
hope this helps...
http://www.diyaudio.com/forums/showthread.php?s=&threadid=9557 (http://www.diyaudio.com/forums/showthread.php?s=&threadid=9557)
btw, in case you're interested in diagrams using the bridged, paralleled and bridged/paralleled configurations, i've got something you might be able to use (courtesy of joan2). i suggest you try to give joan2 a holler.
keep us posted. good luck...cheers
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I just plan to build the low powered one, might just use a simpler circuit but still add a buffer if possible. The tricky part here is what design for the power supply will I use :) I've got data sheets for lm3886, lm3875 and lm1875, might just do the one in the lm1875's data sheet though sinc eI have 4 l1875's at hand already :)
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Updates anyone? Hey John5479 have you got that tube buffered gainclone up and running yet? I'd be interested to know if anyone's finished theirs. Thanks.
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nope aint doin the tube buffered one...almost got all the parts to start building...just need a pair of torroids. I'll be using typical carbon resistors and nichicon capacitors (1000 uF 50v) which I bought from radio shack. Good luck to me i guess hehe.
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a pair of lm3875t's and mur860's just came in this afternoon. transformers to follow...
btw, in case anyone's interested. i got the mur860's as samples. pm na lang for details.
cheers...
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ramble_on pm me naman where you got the mur860s or if you have some spare ones you can sell..thanks :)
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a pair of lm3875t's and mur860's just came in this afternoon. transformers to follow...
btw, in case anyone's interested. i got the mur860's as samples. pm na lang for details.
cheers...
Hey may I know how to get samples? Do you just go to National Semicon site? Guess will just try it. Now the you have the chips maybe you can try prototyping one using the cheapest available capactors. I did with mine yesterday just to see if I could make it work, using P20 caps, P1 resistors, and a P170 3 amp transformer 12-0-12, and P10 4amp rectifiers available at my local shop. I put the whole thing in an Amazon box. It works alright and no hum.
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Hey may I know how to get samples? Do you just go to National Semicon site? Guess will just try it. Now the you have the chips maybe you can try prototyping one using the cheapest available capactors. I did with mine yesterday just to see if I could make it work, using P20 caps, P1 resistors, and a P170 3 amp transformer 12-0-12, and P10 4amp rectifiers available at my local shop. I put the whole thing in an Amazon box. It works alright and no hum.
tried it out with speakers already? comments on sound quality?
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sory for the late reply. @ garp and john, sent you both pms
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garp, was your transfo (12v-0-12v, 3a) able to power the lm3875t without difficulty? how did it sound? thanks.
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thanks for the link ramble_on will try my luck there :) hope the three of us working on these projects will be able to post up some pics of these amps here ;D
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tried it out with speakers already? comments on sound quality?
My first impression was that sound was clean and clear with no hum even from a one meter distance--that's really good considering my ground bus is only a 22awg magnet wire from RShack. I immediately noticed the bass which seemed more prominent here than using my Onkyo receiver. I can't yet make a more detailed comparison because the transformer melted after an hour of play and I used a very old pair of sony speakers (dunno impedance and sensitivity). The chips though and the heatsink were not even warm to the touch.
I initially tried using a 1 amp 12-0-12 but this one can't even cope with moderate listening levels.
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thanks for the link ramble_on will try my luck there :) hope the three of us working on these projects will be able to post up some pics of these amps here ;D
Will do that. My workmanship though will be screaming newbie! to anyone who will have the unfortunate chance of viewing it. ;D
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My first impression was that sound was clean and clear with no hum even from a one meter distance--that's really good considering my ground bus is only a 22awg magnet wire from RShack. I immediately noticed the bass which seemed more prominent here than using my Onkyo receiver. I can't yet make a more detailed comparison because the transformer melted after an hour of play and I used a very old pair of sony speakers (dunno impedance and sensitivity). The chips though and the heatsink were not even warm to the touch.
I initially tried using a 1 amp 12-0-12 but this one can't even cope with moderate listening levels.
well its consistent to what the builders say about gainclones..clean clear and has bass...might want to try a heftier power supply then.
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@garp, pics pics pics ;D
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I actually took pics already but don't know where to upload--if you want I can send thru your email? I'm a little shy about showing it (not showing it off) because its got the words "newbie" and "amateur" written all over it ;D---I've seen the insides of Rene's 300B and the workmanship just makes me want to weep.
I bought another 3 amp 12-0-12 transformer (Star Vox brand for P215) this morning and within 2 minutes of connecting it to my system I can smell plastic burning, so I figured there must be something wrong with my connection, maybe a short somewhere so I simplified things: I disconnected the other bridge and decided to use only a single bridge this time and rewired the thing. Maybe a faulty diode is causing it. This cured it and the transformer just goes warm not hot. I tested the amp again---I get 15+ and 15- DC on the rails this time and 0.5 millivolt dc offset.
I finally connected it to my Missions and listened...whoohoo!!!! I just could not believe that something costing not more than P1,500 (P800+ for the chips) can sound as good as this! Maybe I'm biased but the amp really blows away my Onkyo TXSR500 (ok fine maybe I'm coming from a low standard, mid-fi you might say) at least on two counts: clarity and bass. The bass is more defined and I can hear things I never heard with my Onkyo bass-wise--and I'm using only 1000 uf per rail (I'll be using 2,200 per rail in the real version). I played the Chicago soundtrack and the low end oomph is just amazing. The thing that struck me also within a few seconds of play is the soundstage---the speakers sound bigger. I simply can hear more if the instruments.
The amp can sound really loud but at almost max volume and without any signal you would here a nasty hum. At my preferred however listening levels however I don't hear hum even without a signal. There is however a lot of room for improvement as I'm using only a 22awg ground bus connecting my signal star ground and power star ground. In fact everthing in the amp--signal and power wires--are just 22awg magnet wires from Rshack. I just used "sphagetti tubes" to isolate the wires. The limitation on the power supply however showed when I played a Ray Brown CD: at very loud listening levels enough to for our glass windows to vibrate, the clipping becomes audible. Sometimes you can hear soft ticks at loud listening levels.
Here's what I used for my ultracheap prototype:
ST or SV 1000 uf 50 V filter cap (P20 each, P80 total)
4.7uf Y.c. bipolar (P15 each, P30 total)
resistors 10K, 18K, 22K, 220K (P1 each, P8 total)
4amp 600v ST diodes (P10 each, P40 total)
3 amp 12-0-12 trafo (P215)
Radioshack magnet wire (P130+ a pack)
Binding posts (P30 pair, P60 total)
RCA sockets (P30 pair)
IEC outlet (P59 at Rshack)
terminal block (P20 each, P40 total)
Perfboard (P80 at Rshack)
Fuse 2A slo blow (P30 a pack I think)
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glad to be back,
congrats to you on your gainclone sortie, i also got my samples of 5pcs lm3875 and lm4701....i have given my deisgn for power traffos to podmoon in legarda, you can ask nelia about them, sizes available are 150va, 250va, 350va and 650va...
as for my own gainclone, this is how i plan to proceed,
1. 4pcs lm3875 to be wired paralled/bridged mode to give me 200 watts into 8 ohms and about 300 watts into 4ohms, this will drive a sub-woofer in mon,then,
2. 4pcs lm4701 to be wired in parallel to geive me 60 watts into 8 ohms with two channel,
3. a built in electronic crossover network with crossover frequency of 120hz.
will use this setup for my pc sound system to replace my altec lansing acs33 system... i'll be using the 650 va, power traffo, 16pcs mur860 rectifiers, filter banks consisting of 22,000ufd/63v nichicon filter caps for the subwoofer, 4700ufd/50v for the satellite amps...
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@garp, sent you pm. thanks...
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just talked to nelia of podmon, prices range from 300 to 900 bucks, the 650va is actually a 750va one, you can order any va rating you desire, from between 150 to 750va...using my basic design with a 50volts center-tapped secondary....or any addittional secondary windings you may need....
there's another good link at diyadio:
http://www.diyaudio.com/forums/showthread.php?s=e3f40dc1ef73cc521b4f24e068a7d690&threadid=19593&perpage=15&pagenumber=1 (http://www.diyaudio.com/forums/showthread.php?s=e3f40dc1ef73cc521b4f24e068a7d690&threadid=19593&perpage=15&pagenumber=1)
please check this out...it is very informative indeed...
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Hi Joan2,
Thanks for the great link above. I really like the chassis but my question is is: How important is keeping the signal path really short? The chassis in the link you provided looks really neat but I noted the very long signal path. I've seen the images of the PD Amp that was reviewed by Sixmoons and the signal path seems 3-4 inches only?
And oh, thanks for starting this topic.
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reason for short signal path is to minimize stray coupling effects, ie less noise, sheilded wire can be used if the signal path can not be made very short...if you are reffering to the sselector, and volume control wires, you can use shaft extenders so that the signal path can be made shorter......i started this thread to give readers an alternative to tube amps...i am of the opinion that good sound need not be expensive...and i believe the the myth about tubes being superior to solid state is just that..a myth....
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reason for short signal path is to minimize stray coupling effects, ie less noise, sheilded wire can be used if the signal path can not be made very short...if you are reffering to the sselector, and volume control wires, you can use shaft extenders so that the signal path can be made shorter......i started this thread to give readers an alternative to tube amps...i am of the opinion that good sound need not be expensive...and i believe the the myth about tubes being superior to solid state is just that..a myth....
first of all congratulations to those who made it. DIY is great and I'm a supporter of DIY whether solid state or tubes. I have made transistor-based and chip amps too.
joan2, you should get credit for supporting the people in this thread, kudos to you.
however, joan2, what you called a 'myth' are people's choices. if a person prefers tubes over solid state, do you call that a myth? if a person says solid state is better than tubes, will you call that a myth?
I'd like to hear you comment on this post:
I just could not believe that something costing not more than P1,500 (P800+ for the chips) can sound as good as this! Maybe I'm biased but the amp really blows away my Onkyo TXSR500
you see, i understand people being passionate, as i am as too. but i know how to respect other people's choices and opinions.
i hope your comment is just a slip of your fingers...
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you see, i understand people being passionate, as i am as too. but i know how to respect other people's choices and opinions.
i am sorry to touch your sensibilities, but i am expressing my opinions too.....there was a time tube amps died from maintstream audio....now only monied poeple can afford tubes, here in the phils...i am just pointing out a cheaper alternative.....
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joan2, i think we're on the same boat as far as offering cheaper alternatives go, undoubtably.
i also share the same opinion as yours that good sound need not be expensive, as you stated.
i started the cheap tube projects at wiredstate, and it caught some serious attention i would say.
you also stated your belief, and a belief is not an opinion, so i called your attention. and no, you have not touched my "sensibilities" as what i'm merely pointing out is what is fair. ;)
so going back to the project, you have some nice lineup ahead i can see. :)
i also wish i have the tools, materials and talent as that of peter daniel, he he he. ;D
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arnoldc,
let us build up on our common beliefs then.....
peter daniel has imagination, lots of tools, resources readily available to him....but talent, i believe we are not far behind....
anyway, a good machine shop with vertical milling, possibly cnc, box benders, guilotine shears, bench drill press, a small lathe machine and we are in bussiness...
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Hello!
Is the LM4780 available here in manila? If not, i'll use the LM3886.
thanks!
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you can try farnell, or rs components, but these ics can not be purchased in raon as of the moment,
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you can try farnell, or rs components, but these ics can not be purchased in raon as of the moment,
Thanks for informing me that these ICs are not available in raon at the moment.
I'm planning to use the gainclones for my HT setup. I don't have enough budget to buy myself a decent 5.1 or 6.1 channel amp/receiver so my alternative is to build myself a 3 channel amp for the center and surround channels.
What I need is something like between 60 and 200 watts per channel. If a single LM4780 (bridge) is cheaper than four LM3886s (BPA-200 circuit) per channel, then that's what i'll use...that's if its available here.
If not, i might as well use one LM3886 per channel. That'll be 60 watts per channel into 4 ohm load.
Its good to be back in this hobby again.
Suggestions are welcome. :)
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afaik, LM4780 (bridge) is likewise unavailable here, the device is just two chips encapsulated into a single package, so construction wise it should be the same as the single chips such as lm3875 and lm4701...
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sir joan2, sent you pm. thanks.
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got 16 pcs of mur860's thru onsemi's samples program, now I just need the trannies and off I go! ;D
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Hi John5479,
How long did it take to get the mur860's. I had them ordered at onsemi last Thursday.
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roughly a week..they came in a fedex box shipped from hong kong..but guess what? the diodes are assembled here in pinas ! now to use a torroid or not? hmmnnn
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ramble_on
i did not get your pm, how then may i help you?
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...and i believe the the myth about tubes being superior to solid state is just that..a myth....
interesting comment. i also believe that the myth about the best solid state (amps) sounding close to tubes is also just that...a myth. :)
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interesting comment. i also believe that the myth about the best solid state (amps) sounding close to tubes is also just that...a myth.
i know of no one claiming that solid state is superior to tube amps....there are good solidstate designs as bad ones, same with tubes, there are good deisgns and there are bad ones..i know one area where tubes are clearly superior to solid state, and that is the cost....it is never a question of one being superior to the other, there are many other factors to consider, the amplifying segment is just a third of the whole "music reproduction chain" we still have to look at the signal sources, and speaker systems....no one can win any arguments with subjectivism, after all your ears are the final judge, next of course to your wallet....music reproduction should be an enjoyable experience. the fun fades as one becomes more and more obsessed with wat they do not have!!!!
you see, it has nothing to do with solid state or tubes, it has a lot to do with the individuals' attitude!!!!!
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stupid q. but I will ask it anyway, I am using caps with 35V rating, what is the max. voltage for tha trannie can i use? ???
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I think you should use 18v secondaries that gives you a dc of 25v on the rails. with 25v on the secondaries, you won't have much headroom. What caps are you using for filter and the input cap/dc blocking?
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i'm using 1000 uF for the filter caps, no input cap, skipped that part. let's see 18v secondaries ~25 v which equates to ~12 watts, will try it out then. thanks
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stupid q. but I will ask it anyway, I am using caps with 35V rating, what is the max. voltage for tha trannie can i use?
not a stupid question at all, but rather a good question, to answer, any dc voltage developed from the secondary of your trannie should not exceed the rated cap dc working voltage, so in this case anything below 35 volts is safe.....to calculate, that's 35/1.4 or 25 volts ac, say 22 or 24 volts is fine....even if you use 25volts dc as rail voltage a capacitor rated at 35 or even 50 volts will do just fine....
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thanks will just try 20v then i plan to do a dual mono even if it the power rating is just like ~15 watts per channel, just wanted to get an idea on how to construct an amp :)
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joan2, saan nga yung nag be bend sa aranque? yun ba malapit sa benavidez?
i will make a chassis with top and bottom acrylic sandwich yung bended aluminum kasi.
also, may pogi ka bang heatsink na pwedeng i-recommend?
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arnoldc,
di ko alam yung exact address, per naroon lang yon sa vicinity ng aranque, you can buy your aluminum from sulimco cut to size, give some allowance, cause crude ang cutting methods nila, then there are nearby shops doing bending, there is one shop owned by " pio" a chinoy, then there's another one accros the steet from aranque, this one has a box bender.............last time i went there was in 1994, before i went overseas as an ofw....as to heasinks, we are only limited to what's available at either deeco or alexan, invensting in an extrusion die costs around 50thou...and another 50 thou for a minimum order so it is a costly proposition, wish i had that money.....
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thanks joan2, tingin ako ng heatsinks sa RS or Farnell.
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i have several lm3386 and lm3875, lm4760 and lm 4780 inbound from hongkong......
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i have several lm3386 and lm3875, lm4760 and lm 4780 inbound from hongkong......
bro, how much for a pair of lm3875 ? planning to build one :)
thanks
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bro, how much for a pair of lm3875 ? planning to build one
please call me at 6438957....
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joan2, nice talking to you. see you next week then :)
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hi joan2
im also interested with a pair or 4x of you lm3875, if may naiwan pa.
im planning to build a lm3875 amp.
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i have only a pair left, but will get more in two to three weeks time....
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i have only a pair left, but will get more in two to three weeks time....
joan2, paki reserve na lang yung last pair mo. called you several times this morning but you were out. i got a chance kasi to pass by Shangrila around 12nn. thanks :)
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rmpmla,moonshow,
i have a pair for each of you...no problem..btw, good caps, such as elna, rubycon, nichicon can be purchased at eleshop, the one besides oriental diagram center in raon.....
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Yes! thanks joan2..
ill call you later for details and pickup.
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sir joan, i'm interested in the lm3886 4pcs.
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homer,
please call me at 6438957...
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joan2,
sent you a PM. :)
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just finished my gainclone and its not a pretty sight! the sound was great, better than my old amp. but, my gainclone's life was pretty short, just less than two hours. it shorted after awhile, i clumsily mishandled a bunch of wires and it touched the heatsink, then kapoof, number 4 pin from my lm3875 chip exploded with a bright spark.
does anyone who has built a gainclone experienced echoed sound and sometimes the lack of voice? this is what i have experienced in my mono gainclone.
mang tony, pls reserve me the 3 lm3875 chips that you have.. thanks for your patience.
thanks to:
google.com
decibel dungeon
mang tony
jay gatchalian
and the various electronic shops at raon that have the most annoying salesladies that feels they own the store and we owe them.
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well, we all learn from our mistakes, at least you got it working, being a newbie at that, so this just shows that this gainclone chip is the easiest first project to do, voltages involved are not that high..the important thing is that you incurred no injuries, i must and always have emphasized safety first when working around electronic circuits!!!!
does anyone who has built a gainclone experienced echoed sound and sometimes the lack of voice? this is what i have experienced in my mono gainclone.
i was thingking about this last night as we speak on the phone, and i realized that this must have been due to the SPIKE circuit on the chip acting up...on normal use, meaning that installation is fixed up and sifficient heatsinking was provided, this should not happen...
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joan2,
sent you a PM. :)
please call me na lang sa 6438957...i did not get your pm...thanks
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just finished my gainclone and its not a pretty sight! the sound was great, better than my old amp. but, my gainclone's life was pretty short, just less than two hours. it shorted after awhile, i clumsily mishandled a bunch of wires and it touched the heatsink, then kapoof, number 4 pin from my lm3875 chip exploded with a bright spark.
does anyone who has built a gainclone experienced echoed sound and sometimes the lack of voice? this is what i have experienced in my mono gainclone.
mang tony, pls reserve me the 3 lm3875 chips that you have.. thanks for your patience.
thanks to:
google.com
decibel dungeon
mang tony
jay gatchalian
and the various electronic shops at raon that have the most annoying salesladies that feels they own the store and we owe them.
Same experience here. I blew up one of my chips after a resistor accidentally touched the heatsink---I forgot to unplug the thing before working on it. I'll will make sure I use an isolation pad and washers for the chip in the final version. I got it to work nicely the first time I built it---none of the echo that you noted. The sound was expansive and dynamic and for a 160VA trafo and it gets really loud. The only thing I don't like about it is that it can get pretty edgy at the top but the detail is really superb IMHO. I'll be adding a tube buffer in the final version.
One thing I noticed is that everytime I noticed any problem with the sound, the heat sink temp rises dramatically within 20 seconds of play even if the volume is just enough to hear the sound squeak. It gets so hot that you won't stand touching the heat sink longer than 10 seconds.
The working prototype I built which worked did not hum at all even at full volume (the cd is in pause and I jack up the volume to max level), no transient noises at switch on or off and gets just moderately hot after 2 hours of play at my listening levels. I hope I'll get as lucky with the final version.
I
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and the various electronic shops at raon that have the most annoying salesladies that feels they own the store and we owe them.
Oo nga eh. Was at Raon last Tuesday and I was looking for LM3875 although I found some at the store near Eleshop they're selling it almost twice the price I got my first pair. I got me a pair of SK18752 in Raon from NS also which is rumored to be the one used for the Gaincard. When I got home I fired it up but it sounds really bad--almost like the ones used for portable radios. I'll definitely use LM3875 although I still have a pair of 1875s which I haven't tried. I'm quite curious however about the SK3875. Its a 5 pin chip like the 1875 and sells for P400 each at Newport. A lot of guys at the DIYaudio.com have been looking to try this chip.
Oh Joan2, sorry for misleading info about TDA7294. But its true its available locally although I don't know where in Raon. I do know the local store here in Cavite has them because I've inspected them myself and they're selling it for a little over P200. Farnell is selling these at P716 each.
Thanks for the tip Joan2 on eleshop although I didn't buy any caps there. I was able to buy from them two huge heatsinks. They also have knock down casing suitable for gainclone but made of thin aluminum. The smallest one sells for P350.
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garp,
no problem....from the web the tda7294 is not as good as the lm3875, that is why most diy'ers choose the ns chip over the sgs one, the tda afaik has mosfet ouput devices while lm3875 have npn bjt's in a quasi-complimentary mode....
guys,
i must emphasize you all that while the amp is live, do not touch anything!!!, if you must do something, turn off the power and give 5 secs or so for the caps to fully discharge....this way we can minimize loss of the chip...
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grap, where did you buy your insulation pads?the pads i used was mica and not really for ic chips.
i also noticed the heating of the heatsink after every tweak i did. the only time it normalized was when i perfected the grounding of the cicuit. btw. how big are your heatsinks? and what chips are you using? thanks
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are insulation pads the same as the ones they have at radio shack? i passed by radio shack in ali mall the other day and they have thermal pads. are they the same?
also, i was looking at scrap stuff we had at the office and i came upon some unserviceable motherboards (not the pc type). they had chips much like the 3875s and there were these small stamp-sized grey things (rubbery cloth-like) which were in between the chips and the heatsinks. i was wondering if these were the same insulation pads mentioned.
btw, congrats to moonshow on your first successful outing.
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if you are reffering to the grey colored insulation pads, they work the same as a mica insulator, except that you do not have to use silicon grease, therefore easier to use...btw, when using mica insulators, just smear a thin film of grease just enough to make it opaque, otherwise too much grease is also no good....keep it coming guys!!! there's more lined up....
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guys,
how about this, you can buy surplus amps, price is about "1500 as - is" or you can go to the pier where they sell these stuff and get one which is unrepairable, an integrated amp would be nice as you can use the preamp section, choose one which has main filter caps with voltage ratings of 50volts or less...this way you can have a gainclone amp that looks like a branded one, i m willing to guide and assist anyone wanting to go this way!!!!
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grap, where did you buy your insulation pads?the pads i used was mica and not really for ic chips.
i also noticed the heating of the heatsink after every tweak i did. the only time it normalized was when i perfected the grounding of the cicuit. btw. how big are your heatsinks? and what chips are you using? thanks
The heatsinks I used for the prototype were the usual type you see at Alexan about 3x4 inches with fins. But I'm going to use large heatsinks on the final that will double as sides for the amp case, so all i need is the front plate, back and top. Might just go with wood (thinking of lawanit para cheap lang) because they're easier to do. So far its the amp case that's given me a lot of headache.
Yes I noticed that if you're grounding is ok, the heatsink stays cool and the sound is as it should be. For insulation, I might use mica pads because I already have them. I used lm3875s for the prototype/rats' nest and Ill use these for the final.
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garp,
i go for aluminum housing, i buy cut aluminum plates from sulimco metals in aranque, then have one of the local shops near by do the bending and forming for me. i use ga18 or 16 for covers, ga14 or ga13 for the main housing, this way, you may use the chassis as heatsink also....front panels, i also buy 3/16 in aluminum plates, then have it machined by a machine shop...aluminum is very easy to work with...you need an eletric drill, files, sandpapers... then you can have your housing anodized matte black, or any collor you like....gem metals in makati is one such shop...
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Great! Thanks for the info.
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Interesting thread here... anyone got a BOM, where to get them and price? Any pics to share for completed projects? Congratz!!!
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Leiko .
please read the earlier postings, you will find links to get your bom, fyi, these gainclones operates an an op amp, with higher supply rails +/-35, so you can configure these chips same way as you would an op amp....welcome to the club!!!....btw these chips can be purchased thru rs components at 450or so per chip...
here are some pics you might find interesting!!!
http://www.geocities.com/react_71/audio/index.htm (http://www.geocities.com/react_71/audio/index.htm)
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here are some pics you might find interesting!!!
http://www.geocities.com/react_71/audio/index.htm (http://www.geocities.com/react_71/audio/index.htm)
That's neat! Ayos yung pictures nung gainclones nya. Ano po bang mas ok, separate PCB's per channel or sa isang PCB lang sila?
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no need to do pcb's, p2p is fine, this way you can make the signal path very short....
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no need to do pcb's, p2p is fine, this way you can make the signal path very short....
ok. thanks!
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i got this dynaco sc120 circa 1966 ss amp for repair, looks like a good candidate for gainclone chassis if i can convince to owner to give to me to use in my gainclone project....
here is what it looks like:
http://home.indy.net/~gregdunn/dynaco/components/ST120/index.html (http://home.indy.net/~gregdunn/dynaco/components/ST120/index.html)
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lm3886's are available at newport electronics evangelista for p270, p275 for isolated. bought 2 lm3886t's but can't confirm yet if these are origs.
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homer,
this is great news, lm3886 sells for 450 at rs components in makati...i have the original lm3886 with me, i will check out the item at the store and will confirm to you if it is genuine or not.....i hope it is genuine....
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there are some incredibly cool implementations of this amp design. i have no talent for doing this, but i drool at the prospect of owning one. papano naman kami... hehe.
1) http://www.geocities.com/react_71/audio/gainclone/gainclone_pics.htm (http://www.geocities.com/react_71/audio/gainclone/gainclone_pics.htm)
2) http://www.diyaudio.com/forums/showthread.php?s=&threadid=9112 (http://www.diyaudio.com/forums/showthread.php?s=&threadid=9112)
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akyat,
if you can solder, i can guide you to build one...nothing beats having amps built by your own hands....branded amps sure looks nice, but the one you make is one that you will enjoy the most.....
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naku sir, takot ako dyan.. i once tried soldering a spy radio microphone kit and i burned the thing in 10secs.. ;D
im more of a software guy, and this leaning can be judged by the number of amps that've blown because of my clumsiness.. hehe. plus i live in a building where the fire alarms go off at the first hint of smoke. (daming palusot no?) anyway, im one of the curious bystanders here who are checking to see if this eventually becomes a project for the masses ala wiredstate. my dream - a custom tube preamp and monobloc ss power amps. maybe pinoydvd should have a list of projects for the members? a fellow member built a pretty good dvd rack for me for a good price.
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homer,
this is great news, lm3886 sells for 450 at rs components in makati...i have the original lm3886 with me, i will check out the item at the store and will confirm to you if it is genuine or not.....i hope it is genuine....
so are these genuine? how different are these from 3875?
btw, w/o refuelling the debate bet SS and valves... just to note that the discussion here about the topic is enlightening. ;D In this hobby, my priorities are pocket first, and ears next. SS has it's good points and valves has its own. It's a matter of where I use them... agree, it's a synergy of all components that makes a failthful music reproduction... not one or two pieces but ALL components kaya minsan napamahal yung hobby na 'to. :(
maybe, my upcoming venture into GAIN will change my belief! :)
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http://www.jeffrowland.com/Concentra%20Page.htm
http://www.jeffrowland.com/review16b.htm
http://www.jeffrowland.com/review16d.htm
http://www.jeffrowland.com/review16c.htm
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http://www.jeffrowland.com/Concentra%20Page.htm
http://www.jeffrowland.com/review16b.htm
http://www.jeffrowland.com/review16d.htm
http://www.jeffrowland.com/review16c.htm
Jeff Rowland uses LM3886!
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is there a night class i could attend that teaches the basics in electronics? preferably with lab so i could practice... i want to learn!
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so are these genuine? how different are these from 3875?
btw, w/o refuelling the debate bet SS and valves... just to note that the discussion here about the topic is enlightening. ;D In this hobby, my priorities are pocket first, and ears next. SS has it's good points and valves has its own. It's a matter of where I use them... agree, it's a synergy of all components that makes a failthful music reproduction... not one or two pieces but ALL components kaya minsan napamahal yung hobby na 'to. :(
maybe, my upcoming venture into GAIN will change my belief! :)
i haven't gone to raon yet, hopefully this week, the lm3886, has stand-by and muting functions, to save energy and to prevent turn-on/turn-off thumps that may be present as a consequence of hooking up your audio gear, the lm3875 on the other hand, has none of these functions, but take nothing out it, this chips is as simple as it can get...you can build the inverting gainclone with just a few components, no need to fab pcb's as p2p wiring will suffice, you can make the signal path as short as you can...best of all this is doable even by a complete newbie as demonstrated by moonshow...it took us about 4 phonecall sessions....this is definetly easier, cheaper, and safer to do as the parts are easy to get, and the voltages very low....nothing to lose, as even high end equipment uses this chip....
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is there a night class i could attend that teaches the basics in electronics? preferably with lab so i could practice... i want to learn!
i am willing to give lessons, if you can organize, the place or venue.....i can give you what i learned in 30 years in about 30 hours or so....
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Hey I'm a newbie too--my first DIY and it actually worked ;D (beginner's luck i guess).
For those who are interested to try but worry that if you make a mistake you'll ruin the chip (like I did with LM3875 and that cost me about P1K), the low-powered cousin LM1875 is widely available in Raon going for less than P100. Its a 5-pin chip and you can use the same schematic (note the pin configuration though) used for the LM3875 except the transformer which should have a secondary VAC of 21 max. If you have 18VAC secondaries, that's close to 24VDC on the rails with power output of about 25W. When you think you can get it right, then you can move from prototype to final version using better quality parts. I did the prototype using the cheapest parts available just to hear whether I will like the sound. It turns out I love the sound. I can't guarantee that you will too but I think it's worth a try.
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ithis is definetly easier, cheaper, and safer to do as the parts are easy to get, and the voltages very low....nothing to lose, as even high end equipment uses this chip....
Agree. But in my case the accident is when I inadvertently grabbed the soldiering iron on the hot end. Lapnos yung kamay ko.
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Agree. But in my case the accident is when I inadvertently grabbed the soldiering iron on the hot end. Lapnos yung kamay ko.
hindi ka nag-iisa, i still bear slight scars at the back of my hands from my tube days, they touched the hot side of the 450volt filter caps....
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I did the prototype using the cheapest parts available just to hear whether I will like the sound. It turns out I love the sound. I can't guarantee that you will too but I think it's worth a try.
congratz!!! wish i have same luck on my own try. any comparison to the sound produced by your clone against your other amp/s?
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congratz!!! wish i have same luck on my own try.
can't see why not!!! you can do it....
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i am willing to give lessons, if you can organize, the place or venue.....i can give you what i learned in 30 years in about 30 hours or so....
thanks for your generosity sir! i'll try to visit you this weekend, ill bring my "sick" amp.
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congratz!!! wish i have same luck on my own try. any comparison to the sound produced by your clone against your other amp/s?
Thanks. But I ruined the chips as I was trying to add a buffer. In terms of sound ok I'll give you my impression but this comes with a big disclaimer because 1) My benchmark is only mid-fi--my onkyo receiver 2) I may be actually falling into "experimenter expectancy" here 3) I have not listened to it long enough to be sure I've broken it in.
The sound is very clear and detailed. Soundstage is wider and imaging is more precise. What's very noticeable is the bass control giving the impression that its "fast" and very lively. My observations are in line with the consensus here. The bad thing is its fatuiging. It's very edgy at the top. Vocals which were not sibilant in my Onkyo were sibilant in the gainclone. Again, this could be the result of the highs being too detailed. This is also what's reported by other DIYers but according to Peter Daniel, the way to improve the highs is by putting 4.7uf BG Non-polar caps across the rectifier diodes. This according to him cured the edgy top end. What Joe Rasmussen proposes however is to implement a Low pass filter. I will try the LPF in the final version.
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to implement a lowpass filter with the gainclone is easy, you can put a small capacitor accross the feedback resirtor, the one from output terminal to the inverting terminal, this will roll-off the response at hf somewhat, you can start with a 0.0056uf cap...
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Thanks for the tip Joan2. When you say 'across,' is that the same as bypassing the feedback resistor with the small cap? Would mylar be ok to use?
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garp,
yes, mylar will do, bit if you can find polystyrene types, that will be better....
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just pushing my luck... will anyone be kind enough to modify and publish a revised inverted gain (Loesch) schematics with the additional tweaks (2) mentioned above -- to address sibilance/edgy? (that's something am very allergic about ;D)
well, i know, i have to get my feet wet first....
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Hi leiko, you can try either what Joan2 said about paralleling a small cap with the feedback resistor or you can look at the schematic by Joe at http://members.ozemail.com.au/~lisaras/ (http://members.ozemail.com.au/~lisaras/). He offers both a tube and non-tubed version of the gainclone. What's common for both is the use of the LPF.
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where can you get blackgate capacitors here?
or any nichicon\rubycon ones, that has 1000uf 50v capacity. i have only seen the jamicon/jakon brand and i don't know if they are any good.
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You can't get them locally. Silver Strings offer blackgate caps but not the values you want. Best and easiest way would be Farnell or RS for nichicon PL /rubycon ZL/panasonic FC. Look for low impedance types. Panasonic FC is the cheapest and is highly recommended by other builders. Jackon was what I used for my prototype.
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joan2, sent u pm 8)
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Hi leiko, you can try either what Joan2 said about paralleling a small cap with the feedback resistor or you can look at the schematic by Joe at http://members.ozemail.com.au/~lisaras/ (http://members.ozemail.com.au/~lisaras/). He offers both a tube and non-tubed version of the gainclone. What's common for both is the use of the LPF.
yes, a lo pass filter at the input is also imho a more stable option......
to those contemplating on building gainclones, do not hesitate, tech-support is available here for free!!!
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interesado rin akong mag diy ng amp pero para sa bass shaker lang ... 50W, 8-ohms ... balak ko LM3875 gamitin as inverting amp para makabawas sa piyesa
tanong ko lang mga sirs:
1. mukhang ang available lang na LM3875 ay yung non-isolated tab (LM3875T), meron bang available na insulator? kung wala, ano remedyo nito? tingin ko pwede yung mica insulator ng TO-3, nasubukan nyo na ito?
2. wala naman siguro masama kung putulin na yung mga NC na pins noh? para hindi na sagabal sa p2p wiring ... limang pins lang importante, anim yung NC
salamat po :)
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kinyo,
pwede yung mica insulator for to3, but mica for to3p transistors can also be used, this is bigger than that of to220 and available in raon...be sure to use silicin grease though....yes you may cut the unused pins on the lm3875 to facilitate p2p wiring....
here is the gainclone picture gallery:
http://www.decdun.fsnet.co.uk/gcgallery.html (http://www.decdun.fsnet.co.uk/gcgallery.html)
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hi,
i'd like to ask everyone here who has heard the sound of the gainclone, for what types of music does this amp sound the best?
thanks
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thank you sir joan2
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kinyo,
mukhang wala ka ring magawa 'no? DIY ka na rin. Just like the good old days when you were an EE student pa sa UP. Good luck bro!
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to those contemplating on building gainclones, do not hesitate, tech-support is available here for free!!!
very comforting... i seem to lean towards tubed-GC....
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Hello everyone,
This is my first time posting in this great forum, thanks to joan2 who showed me the link in here from another forum.
I have built a lot of amps, ss and gc only, I have not been into tubes because I never had the chance to have my hands on some. Besides, when I was in elementary, it is ss already that is widely available.
As for gc, I have used them in a design for a switched paging system in a huge textile plant. 8 bldg but only one control system. It's been years but it still works. I used chips from SGS-Thompson (TDA2030, 2040, 2050) in that plant.
Recently I have built a gc for a 12 inch Targa DVC sub and am still amazed. Makes them small chips sound huge!
As for parts, I have used the most cheapest parts from raon with surprising results.
Best regards,
JojoD
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welcome to the forums jojo!!!
kinyo,
this link is a continuing saga of gainclone diy:http://www.diyaudio.com/forums/showthread.php?s=&postid=249422#post249422 (http://www.diyaudio.com/forums/showthread.php?s=&postid=249422#post249422)
this sub-amp idea may appeal to you:http://www.diyaudio.com/forums/showthread.php?s=&threadid=18859 (http://www.diyaudio.com/forums/showthread.php?s=&threadid=18859)
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hyperaudio,
gusto ko lang magkaroon ng dedicated amp para sa bass shaker ko kasi ngayon gamit ko yung lumang Pioneer AVR ko, overkill naman yun dba? pinag-iisipan ko pa kung LM3875 ang gagamitin ko or yung LM12 (80W TO-3 package, more expensive nga lang) kasi baka bitin yung 50W ng 3875
joan2,
thanks for the links ... sir, nasubukan nyo na ba yung LM12? balak ko rin gumawa ng active subwoofer kasi meron na akong subwoofer controller kit na nabili ko sa net
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kinyo,
the lm12 is a to-3 packaged device, mas cumbersome to mount on a heatsink, costs around 1200 at Alexan, but with 6 lm3875's you can get the same output at a cost of 1260 as compared to 2400,
for my own setup, i will be using 6 lm3386's in a bridge/parallel configuratuion for a subwoofer-amp that can drive 200w+ at 8R, and 4 lm4701's in a bridge mode that can drive around 60watts at 8R, for mid-highs, i will be using an electronic crossover with a lo-cutoff at around 120hz...i will be using an ei traffo rated at 750va which i will be making myself, and a mains filter consisting of 22KuFd/63volts, by-passed by a film cap of 4.7ufd/100v..this is for my pc sound system to replace my existing altec lansing ACS33 spkr.....
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to those who would like to get their hands at free samples of Burr-Brown OPA541/549 gainclones you can visit this site and register:http://www.ti.com (http://www.ti.com)
i already ordered mine, although limit is 2-3 pcs of each kind....
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gc,
been to raon just now, newport sell good ic's i have not had sad experience buying semicon parts from that store!!!!!
smg, sells a 24-0-24 volts @ 6amps power transformer fopr 340 pesos, this is a good buy, but i would rate that traffo as 240va...so you can take this into consideration when assembling you rgainclones....
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Speaking of powered subwoofers, how about class-D chips for subwoofers?
LM4651 and LM4652 (http://www.national.com/pf/LM/LM4652.html) is a 170W class-D solution.
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gc,
medyo complicated, unless we can have access to pcb manufacturer willing to do short runs, expensive proposition yan....
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Hi guys,
If you can show me a design of the kind of pcb you are wanting to be made maybe I can help you. I can make pro looking pcb's but without the silkscreen pattern on the parts side.
You can find a picture of a pcb I made in this link: http://www.diyaudio.com/forums/attachment.php?s=&postid=236192
Regards,
JojoD
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jojo,
photo method b un? how about solder resist? how much for a stereo gc?
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Hi homer,
I can only do single layer, no solder resist, no stencil. The pcb is drilled and covered with anti-oxidant coating.
JojoD
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i do my lay-outs on an illustration board, actual size, then use that as template to drill the holes, i used silkscreen on most of my leach superamps, then masking tape on the ground plane, since circles lang around the holes ang kailangan....i am looking for solder resist paint.......
gc,
this link is what you need?
http://hepso.dna.fi/misc/LM4780/lm4780_amplifier.html (http://hepso.dna.fi/misc/LM4780/lm4780_amplifier.html)
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joan2,
Using silkscreen is a very effective way in making pcbs but it is also hard. Besides, the process in making the silkscreen is expensive even if you are the one making it (photo emulsions are not cheap). To make a fine resolution on silkscreen is also a nightmare ;D. However, our former supplier of pcbs uses the silkscreen method and it takes ordering a pain. Silkscreen is also only used when the pcbs are in the hundreds. Imagine making a silkscreen pattern for 10 pcbs. :o
JojoD
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jojo,
i have my silkscreens done in claro m. recto, i use vynil paints, but you have to use fresh ferric cholride all the time lest you suffer undercutting, i also have some of my artworks done by a printing shop, i have both sets of positives and negatives....
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joan2,
Again, I think making pcb using silkscreen yields superb results, but I don't recommend it for newbies. Too many procedures to follow, besides, cleaning the silkscreen after use must be very thorough to be able to use it again. The last time I check at recto they ask between 250-400 pesos per silkscreen! So care must be taken to minimize cost.
Anyway, I have been asked by others to make pcb for their projects in the past. Maybe after sorting out my stuff I'll start making pcbs for others again. Especially for gainclones and preamps using semiconductors that have 0.1" spacing between pins.
Everyone,
FYI, I have also tried the TDA2030A and the TDA2050 by SGS-Thomson (search google for datasheets) in single-ended and bridge modes. Sound is clean and clear, besides they are cheap. Widely available in the raon area.
JojoD
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jojo,
if you read the earlier post i never mentioned anything about silkscreen, poin2point wiring is the method i advocated as this can easily be done by a newbie as demonstrated to us by moonshow, and the chip of choice was the lm3875, best for simplicity....you'll be surprised though, there are a lot of tube guys in this forum,i have a healthy respect for them as they are not what you may call newbies!!!
i see the tda2030 has max Vcc+/-25 while the tda2050 has +/-25 volts, and 5 pins, nothing could be simpler than this!!! worthwhile to practice on, then use the lm part for some serious clone building for more power!!!
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joan2,
I did read the post from the beginning. My only concern with p2p wiring (with a newbie) is that accidents are very prone. Plus the cold solder phenomenon! ;D Anyways, I know that a lot of the fellows here have respectable experience in electronics. But then again, hooking up a ht and wiring a circuit are two different stories.
As for the TDA amps, they can be used for satellites or other low to medium apps. Another chip that I like using is the TDA1514A by Philips. Again, very widely available in the raon are, very cheap too, gives 50W. Dai-1chi used this in one of their push-pull subs that I have.
The LM3875, 3886 are very sturdy chips that can widstand a lot of abuse, I know because I did some abusing myself. ;D
More power (to all of us),
JojoD
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joan2,
Can you please give me the contact number of sulimco metals? I am thinking of building plate amps for subs (again). I used to sell plate amps for diy subs and planning to be active again! ;D
JojoD
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jojo,
i do not hae the new numbers, but they are right beside the Aranque market, opposite TIP, very near the road, cm recto....
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joan2,
Thanks man! If my "kumpare" doesn't have one in their shop then I have no choice but to get one from suliman.
Cheers,
JojoD
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Jojod818,
Have you tried TDA7294? What's the feedback on this chip--seems widely available too. Thanks.
P.S. just found out this is what was used for nOrh Le Amp I
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Hi Garp!
Fortunately we have tried the TDA7294 using a 35-0-35 trafo. I only used the basic circuit in the datasheet and it performed well under rigorous test. Unfortunately, we didn't tested the "High Efficiency Circuit" in the datasheet that uses two different supplies that improves Pdmax as well as the power handling of the overall circuit. I have a friend who did, his from Canada, all I know is that his happy with the results of the high efficiency circuit version.
As for me, the 7294 is worth your time. FYI, another chip that I tried was the TDA7293 (again from SGS-Thomson). It performs well in my 12" DVC Targa sub. Besides, it only cost 300+ in the raon area. Check it out!
More power,
JojoD
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just got my OPA541/OPA549 gainclones i ordered from TI last week...very fast and hassle free!!!!
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joan2,
thanks for the tip. got my samples OPA541/549 power amp chip today delivered by UPS courier.
now, i need to check for the circuit diagram. :)
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rmplma,
Just download the datasheet and off you go. BTW, I have tried them chips both inverted and non-inverted, bridged and paralleled. It works fine either way. ;D
JojoD
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rmplma,
Just download the datasheet and off you go. BTW, I have tried them chips both inverted and non-inverted, bridged and paralleled. It works fine either way. ;D
JojoD
JojoD,
you've done a neat PCB. pwedeng bang kopyahin ;D.
my email : [email protected]. thanks
rmpmla
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I just sent you the foil side of the pcb, good luck!
JojoD
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just got my OPA541/OPA549 gainclones i ordered from TI last week...very fast and hassle free!!!!
what's the difference between the OPA549S and OPA549T? ???
i was about to order samples but i don't know which one to choose between the two.
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if i am not mistaken, 's' is for single in line, while 't' is for the uninsulated version very much like the lm3875, btw opa541 seems to be higher powered than opa549 since the opa541 can operate at higher rails....the to3 version of the opa541 seems to be the best package if you want ruggedness, although harder to mount on a heatsink...haven't found one at diyaudio yet...
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if i am not mistakes, 's' is for single in line, while 't' is for the uninsulated version....
Thanks.
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joan2,
thanks for the tip. got my samples OPA541/549 power amp chip today delivered by UPS courier.
now, i need to check for the circuit diagram. :)
my 541 are on its way, via ups (per ti email) :o :) .
rmpmla,
please update us if you find a simple amp circuit for this baby (yung pwedeng i-build kahit grade one pupil ;D , newbie ako e.)
thanks,
8)
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For samples, did UPS charge you any taxes?
I'm thinking of adding more samples since I might want to make a preamp if I succeed in making the GC. The popular ones for preamp are available as samples like OPA2134, OPA637, OPA2604.
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i did not pay any....
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Guys,
S= single in line, T= ZIP11 (yun zig-zag yun pins.)
You won't have to pay anything since there is a TI plant in Baguio City. They also have an office in Muntinlupa that will call you up or send you a letter (if you supplied a wrong tel. number) asking you to explain where you used the samples.
Mika,
Yun pcb na send ko kay rmpmla very simple and uses less components.
Cheers,
JojoD
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I just sent you the foil side of the pcb, good luck!
JojoD
thanks for the foil pattern. :)
rmpmla
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rmpmla,
please update us if you find a simple amp circuit for this baby (yung pwedeng i-build kahit grade one pupil ;D , newbie ako e.)
thanks,
8)
Mika,
i will try the pcb layout courtesy of JojoD818. now, i need is the time to build this amp ;D.
rmpmla
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For samples, did UPS charge you any taxes?
wala akong binayarang tax.
actually, i received two packages via UPS. the first package i received yesterday which consist of 7 types of OPA.
the 2nd one i received just today 3pcs OPA2544T.
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rmpmla,
My last 541 used that pcb and it works fine. I used it for evaluation purposes though. :)
JojoD
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Mika,
Yun pcb na send ko kay rmpmla very simple and uses less components.
Cheers,
JojoD
sir JojoD, kindly send me pcb design also, if possible. :)
Mika,
i will try the pcb layout courtesy of JojoD818. now, i need is the time to build this amp .
rmpmla
yes sir rmpmla, excited na ko :) , just take your time ;).
thanks for the replies,
8)
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Mika,
No problemo! Where do I send it?
JojoD
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rmpmla,
What I sent you is the foilside! OK? I will send you another one with the parts placement guide.
JojoD
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Mika,
No problemo! Where do I send it?
JojoD
alright!!! you're the man sir jojod818.
yohooo!! :)....
sent you pm
thanks,
8)
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rmpmla,
What I sent you is the foilside! OK? I will send you another one with the parts placement guide.
JojoD
JojoD818,
that would be great! :)
i saw your post on diyforum. pareho pa rin ba ang parts o may nabago na?
rmpmla
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those of you doing the pcb, you can use shellac varnish after you clean the boards so that it doesn't corrode, copper reacts well with oxygen so that it becomes green after a while....a slight coating will do, for cleaning the boards, you may use 'scothbrite' and pumice powder 'ajax' after washing the boards clean of ferric cholride...
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Hi guys,
I just sent the pcb pattern to rmpmla and Mika. Good luck guys!
PS, just finished a 48dB Linkwitz-Reiley Low Pass Filter for my sub project. Excellent results! As soon as I finish my new prototype, I'll share it with you guys.
JojoD
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here is another tip when doing your heatsinks, make sure to de-burr the holes you drilled to make it flat, you can use a bigger size drill bit to do it, say 3/8, then you can lap your hatsink by laying a 600grit sandpaper on a flat surface, prefferably a glass table top, then rub the mounting surface of your heatsink on the sandpaper using regualr even pressured motion, this will ensure that the chip package will mate evenly withe the heatsink, thus more efficient heat transfer can be achieved...if you want you can clean you heatsinks using a lye solution, half a can in a pail of water would be enough..do this in a well ventilated area such as outdoors, as you immerse your heatsink, a pronounced bubbling will take place, half an hour should do it...you can use vinegar to remove any stubborn stains, but in my experience i never had to resort to this...depending on the strenght of the solution and the soaking time, you can have a silvery matt finish....take care!!!!
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Hi,
Follow up lang sa tip ni joan2, you can use muriatic acid (gamit sa cr!) for this. Either way, you have to wash the heatsink well after soaking.
Another ingenous way of heatsinking is to use old pc cpu heatsinks with fan! I've tried this before and yields excellent results!
NOTE: Be very CAREFUL when HANDLING CHEMICALS!
JojoD
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Hi guys,
Just finished a 2 channel OPA549 and got it connected to my 48dB LPF and powered my 12" dual voice coil Targa sub. I used an 800VA transformer and lots of filter caps. These chips are really good, they rock! No problems encountered at all. ;)
Since my sub has dual 4 ohm coils, I plan to series it to get 8 ohms and use a simple bridging converter (currently working on) so that I can bridge the 2 channel amp. The bridging converter is nothing more than 2 opamps with one as a non-inverting and the other in an inverting mode.
I'll post my findings asap. BTW, I will try to upload pics and link it here. :)
Cheers,
JojoD
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if you like to color your aluminum parts, this is for you:http://t6aluminum.tripod.com/Anodizing.htm (http://t6aluminum.tripod.com/Anodizing.htm)
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those of you who missed this, this is a nice read:http://www.decdun.fsnet.co.uk/buildingyourown.html#casework (http://www.decdun.fsnet.co.uk/buildingyourown.html#casework)
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Grrr...was finally doing my hybrid gainclone when I accidentally clipped pin 7 on my LM3875. Probably the most stupid mistake any newbie can make. I sawed off a portion of the chip near the edge so I can resoldier the pin. I hope this will work.
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lesson learned, leave off about 1/8 inch, so in case of mistakes, you can still easily salvage the situation....hey i found an 8fq7 in my junk box!!!!
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Garp,
That's one of the "accidents" I am talking about. :) It should work if only the plastic part of the chip was sawed off. ;)
JojoD
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Yes I think its only the plastic chip I sawed off. I saw someone do it on a LM1875 (pic below) so I thought maybe it should work with LM3875. I'll let you guys know when I've completed the circuit.
(http://home.ca.inter.net/%7Ecfraser/MVC-004FA.jpg)
Craig Fraiser's webpage
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yes, the die is probably 1/16 of an inch away!!! but it should work...
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Garp,
I hope your chip still works, the die is really close...
JojoD
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garp,
after verifying that it works, you put a few drops of mighty bond around the leads and on the sawed off encapsulation part just to seal it, a little precaution would not hurt!!!
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Joan2, Jojod818
Thanks for the tip Joan2--will do that. Hopefully I'll have my tube GC working by weekend! That is if I don't run into grounding issues, oscillation etc. I've actually finished the power supply already and measured DC voltages at the output are just right. I did my measurements with the PS not connected to my amp circuit which is still in the works.
I'm puzzled however that when I put my el-cheapo meter to AC I get a high voltage. So I have an 18-0-18 secondary with one bridge per rail, rectified that's about 25VDC per rail which is ok but when I measure using AC I get something like 65V per rail? I don't get it. I did the same for the filament which is at 5.9 volts and I get a AC of 12+ something. For the tube supply at 33V I get something like 75V AC. And the AC volts I get on one rail is equal to the other rail for all power modules I did. I hope I'm making sense.
And one more question, for my tube supply I'm using EI core 12-0-12v secondaries 3 amp but dual primaries 110v and 220v. To get 24V I instead used the 110v tap instead of the 220. Are there any issues here aside from the mechanical hum I get? I intend to replace it with a better one when I have time to go to Raon but for the moment I'll make do with it.
Thanks.
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Garp,
First, shoudn't your meter be set to DC rather than AC? I think I also experienced that measuring DC with the setting on AC and getting a high voltage reading.
Second, I would suggest that you replace that 12-0-12 with the proper rated trafo. However, all things being equal (which is not) you should be able to use that but it is not designed that way. I mean, 220v is 220V and 110V is 110V, and that's it. ;)
Safety first,
JojoD
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Garp,
First, shoudn't your meter be set to DC rather than AC? I think I also experienced that measuring DC with the setting on AC and getting a high voltage reading.
Second, I would suggest that you replace that 12-0-12 with the proper rated trafo. However, all things being equal (which is not) you should be able to use that but it is not designed that way. I mean, 220v is 220V and 110V is 110V, and that's it. ;)
Safety first,
JojoD
Yes I did measure using DC and the voltages are right and equal on all rails but I read from Joe Rasmussen that you can measure the ripple by setting your meter to AC so I thought maybe that should work. Joe said that one way to troubleshoot the IGC is to measure the ripple on the rails by setting your meter to AC--he quoted a figure at 2-5mv as acceptable. I don't know however if he meant measuring the ripple WHEN the PS is connected to the amp circuit or if you can do that to the standalone PS. I just have this notion--not having a backgrounds in electronics--that when AC has been rectified you shouldn't get AC on the rails.
I agree. Iwill replace the tranny soon but I'll be using it this weekend just to test my circuit. Thanks for your inputs.
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garp,
you are lucky the traffo did not burn-out on you, a 110volt winding fed with 220volts draws a lot of current, that is why the humming, the transformer gets very hot in no time and smoke follows..so as jojo said, safety first!!!!
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Garp,
Your multitester do not have a DC blocking capacitor on its AC setting, which explains the anomalous readouts. Try a not-so-el-cheapo digital multitester.
I have an el-cheapo digital multitester and find it lacking DC blocking capacitor and therefore reads incorrectly, similar to what you observed. It simply half-rectifies the signal so that reversing the tester leads would read zero. But my Radio-Shack multitester correctly reads ripples.
And yes, your notion is correct, after AC has been rectified and filtered by a capacitor, there will be pure DC at the capacitor terminals if and only if there is no load at all, i.e., there is nothing to discharge the capacitor. As soon as a load is connected, ripples will appear at the rails.
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Guys,
I think that PSU ripple is something that we guys must live with. I once read an article (can't remember from where) saying that lots of capacitors and proper decoupling minimizes (not eliminate) ripple.
Maybe our design goal (for the psu at least) should be aimed at having the best psu that we can build for a better sounding amp without blowing our pockets apart! ;D
Cheers,
JojoD
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Forgot to mention that chipamps "usually" have excellent PSRR ratings.
garp,
I think your psu would work just fine. ;)
JojoD
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gem metals in makati is one such shop...
may i know the address?
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got my opa541am, surprised how fast the delivery was :o . the chips came from malaysia, delivered by ups at our office. no payment made, taxes whatsoever.
too excited ordering, i got the to-3 ??? (halata bang newbie). what to do?
what's next?... gainclone building EB :)
8)
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Mika,
The datasheet says nothing about the metal part of the to-3 opa541 to be connected to any pins so I suppose it is safe to install it directly to the heatsink. Be careful though because the datasheet seems to be top-view! ::) You might accidentally interchange the pins.
Wiring it should be the same as p2p wiring a zip11 plastic package.
What's next? Buy the remaining parts needed and do some exciting work. ;D Then fire it up! (Not literally!)
Good hunting,
JojoD
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My OPA541 pcb.
http://www.geocities.com/jojod818/OPA541_Power_Amp.gif
JojoD
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My OPA549 pcb. I hope it shows up though. ;D
http://www.geocities.com/jojod818/OPA549_Power_Amp.gif
JojoD
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may i know the address?
the last time i had anodizing job done was in 1993, in 1994 i went to work overseas(algeria, then singapore) and was back to manila 2001. i have lost my contact numbers, but i know "gem metals" is in makati, i used to request our purchaser to bring my items for anodizing there, there is another one, Echo Metals which is in Hulong duhat in malabon, there is also onother shop here in Pasig, but when i checked them after my return, they have already closed down...that is why i am considering doing it on my own....sorry i could not be much help at this time.....
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got my opa541am, surprised how fast the delivery was :o . the chips came from malaysia, delivered by ups at our office. no payment made, taxes whatsoever.
too excited ordering, i got the to-3 ??? (halata bang newbie). what to do?
what's next?... gainclone building EB :)
8)
best deal in town, congrats!!! the metal types, to3 hermetic is more rugged and i would say have higher package dissipation capability, very rugged, and can last longer than the plastic versions...although harder to mount...did you say gainclone building eb? magandang idea, say mo jojo?
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Ganda nga idea yan! Go go go...
Back to the to-3, If I can just have a technical drawing of the package, maybe I can make a template for a center punch prior to drilling the heatsink.
Yan na talaga best deal in town! gainclone metal madness!!!
JojoD
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Ignore the pcb links, they don't work!
JojoD
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hi joan2, thanks for the heads up. i'll look around :)
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nice work jojod 8)
(http://sc.groups.msn.com/tn/FE/61/PinoyDVD/e/41a.jpg)
click to enlarge (http://groups.msn.com/_Secure/0PwDiAnISjkJUL*E*oqpJpycLsoG2wDRNfQ7W4Pfs4gS2BIIPa8mY*ldnxiCvhMBo3EbrDtsYMQqbAYyCV6XBgEA8*wEfYH76/pcb.jpg?dc=4675445224408706229)
sir posted your pcb, hope it's ok with you.
:)
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Ganda nga idea yan! Go go go...
Back to the to-3, If I can just have a technical drawing of the package, maybe I can make a template for a center punch prior to drilling the heatsink.
Yan na talaga best deal in town! gainclone metal madness!!!
JojoD
eb! eb!
one afternoon maybe, in sir joan2 or jojod's place? ;)
we can mount the circuit in a breadboard(?), experiment in replacing different values of resistor, caps, power supply, etc. how they will affect sound quality.
help a newbie
8)
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hi joan2, thanks for the heads up. i'll look around :)
hi arnoldc, i am also looking for one, even the machine shop thati used to go to for machining my aluminum parts in now gone, i used to own a bench drilling machine but i sold it just before i went to work overseas, that decision i now regret...
mika,
these gainclones are no different to plastic lm301 or lf351 opamps except they can deliver more power, so that analysis of opamps also apply to gainclones....my place? i would love to but i have actually turned our living room into a bodega of sorts...lots of computer parts, monitors etc, but anybody is welcome to go to my place, most number of peple i can accomodate will be three or four....because of the clutters...
The datasheet says nothing about the metal part of the to-3 opa541 to be connected to any pins so I suppose it is safe to install it directly to the heatsink. Be careful though because the datasheet seems to be top-view!
yes, i verified this with my dmm set to read 2k and there is really nothing connected to the case, a real improvement over lm12 i would say....
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about power transformer for gainclones, here is my tip:
1. you can use va(volt ampere) to power output ratio of from 1 to 2. i suspect from the pictures that peter daniel is using a ratio that is closer to 1.
2. example, if you want to use two lm3875 with a power output of 50 watts inot 8R then you transformer must be 100va minimum, if usure about the impedance of you pseakers or that you will want to use 4R then use a transformer with a ratio closer to 2, or 200va say.
3. over here transformers are always overrated, so that if i see a transofrmer being sold as 300va i look at it as a 200va one...
4. the implication is that an overated transformer heats up faster and has a poorer voltage regulation...
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i have another tip for you:
if akyatbundok has his favorite audio shopping mall, me too have a favorite electronics supplies depot, there you can buy all sorts of electronics stuff that you can use, heatsinks, capacitors and transformers. the store owners' name is Mang Oca, his shop is located in Ususan, Taguig...is is along the raod, its the one shop that has junked tv picture tubes in front, the quality of the parts at his store is first rate, and very cheap too!!!
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Hi guys,
Sad to say, I can't host an EB due to some minor renovation work and lots of cleaning work. Maybe after the work is done. :)
joan2,
I agree that the to-3 type is a bit better than the plastic type when it comes to dissipation.
mika,
Posting the pcb is fine, actually sharing the pcb design is what's in my mind. You can visit the temporary site I made for diy electronics for other pcb designs. I will also upload schematics as requested.
Regards,
JojoD
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Mika,
I have uploaded the schematics for the 541 and the 549 on my site. Still no pictures though, maybe later. :(
Go here: http://www.geocities.com/jojod818/
JojoD
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JojoD,
neatly laid components on the PCB for your 150 watts Power Amp. :)
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i plan to install the OPA 541 on my vintage kenwood receiver.
(http://groups.msn.com/_Secure/0QwDLAtsTcJ*uXKB802RPFc3A347Mbe0vss!kpAo5YVUCFtuGSQJ0DIevdG8OVKuzz6P1*ksuiJ8*wfJwW3UKWUEHEunmBJkhchc4oxpgGCo/kenwood.JPG?dc=4675445342421910759)
kaya lang when i checked for the transformer secondaries, the voltage is around 73 AC volts and around 36 AC volts line to ground.
the DC voltage +/- is 96 volts. datasheet of OPA 541 indicates a max voltage of +/-80 volts.
is there a way that i can reduce the voltage? :)
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was able to build one using cheap components just for test on the kenwood reciever.
(http://groups.msn.com/_Secure/0PwDVAn4RqgkIy5TvlNsGemPWJJdyR!xuGlZ7gU0Wa61rgqqWLkhdxtBuAHJPfioqSDafBHLWl!8JAbrepNaZ1588CrQx!svn/541.JPG?dc=4675445342525158592)
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rmpmla,
Wait!!! The datasheet says +/-40V max for the OPA541! You'll fry it at +/-80V :o
Thanks for noticing the 150Wamp pcb. ;) I am currently uploading pics on my site and maybe available soon.
Sad that geocities doesn't allow us to link the picture to forums. If you know a free web hosting, please inform me. ;D
JojoD
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Pictures are up!
http://www.geocities.com/jojod818
JojoD
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Just for your info guys,
The datasheet of OPA541 do say that the case is isolated on page 1, last sentence. Hindi ko rin agad nakita ito so I ordered the plastic package :(
Ayos ang 549 project mo Jojo ... ganda ng layout sa pcb ... i notice there is actually an RC hpf at the input not shown on schematic ... and ZL is actually the usual series RC ... keep it up!
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rmpmla,
Wait!!! The datasheet says +/-40V max for the OPA541! You'll fry it at +/-80V :o
JojoD
my mistake ;D. AC volts is 36v-0-36v. and DC volts is (+48v)-0-(-48v) or 96v between the + and - supply on the kenwood receiver.
would the OPA 541 datasheet translate (+40vDC)-0-(-40vDC) or 80vDC between the + and - supply?
-
would the OPA 541 datasheet translate (+40vDC)-0-(-40vDC) or 80vDC between the + and - supply?
;D I think that statement is just the same ;D
+/-40V=(+40vDC)-0-(-40vDC)=80vDC between the + and - supply
Kinyo,
Thanks man, I didn't see that cause I was hurrying up in my reply. The zobel was put there for added safety measures.
JojoD
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Guys,
Leach amp pics are up! ;D Enjoy pala gumawa ng website eh, sensya na, first time ko eh! ;D
JojoD
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my mistake ;D. AC volts is 36v-0-36v. and DC volts is (+48v)-0-(-48v) or 96v between the + and - supply on the kenwood receiver.
would the OPA 541 datasheet translate (+40vDC)-0-(-40vDC) or 80vDC between the + and - supply?
you actually have the opportunity to eliminate ripples on the rails if you add a series pass voltage regulator for each rail. the regulator will drop the voltage to a safe level at the same time keep the voltage steady (no ripples if designed properly to handle the load). added circuitry ito but it is one option to solve your problem. the regulator will use power transistors too so heatsink is also required.
the easy route is simply to replace the transformer with lower voltage output, say 24-0-24, 3A for a single OPA541 :)
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Guys,
Leach amp pics are up! ;D Enjoy pala gumawa ng website eh, sensya na, first time ko eh! ;D
JojoD
Bagsik ang dating, Jojo! Congrats! Minsan, pinangarap ko rin gumawa nyan, hayun, pangarap pa rin hanggang ngayon.
Wala pa bang nasirang speakers yan? ;D
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i plan to install the OPA 541 on my vintage kenwood receiver.
(http://groups.msn.com/_Secure/0QwDLAtsTcJ*uXKB802RPFc3A347Mbe0vss!kpAo5YVUCFtuGSQJ0DIevdG8OVKuzz6P1*ksuiJ8*wfJwW3UKWUEHEunmBJkhchc4oxpgGCo/kenwood.JPG?dc=4675445342421910759)
kaya lang when i checked for the transformer secondaries, the voltage is around 73 AC volts and around 36 AC volts line to ground.
the DC voltage +/- is 96 volts. datasheet of OPA 541 indicates a max voltage of +/-80 volts.
is there a way that i can reduce the voltage? :)
you need a +40/-40 volts rails, so the only way you can use that is to buid a voltage regulator to bring down the rails to proper voltages...or you can change the transformer to one that has the proper ac voltages, 24-0-24 is a safe figure, it will give a +/-36 volts at no load, suitable for an opa541 or an lmm3886 if you decide to change it later on....take note of the windings of the original transformer, then you have another one made to your specification....the transformer that you will take out from your existing amps can be used for a leach amp later on, jojo and i will help you if you decide on it....
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Bagsik ang dating, Jojo! Congrats! Minsan, pinangarap ko rin gumawa nyan, hayun, pangarap pa rin hanggang ngayon.
Wala pa bang nasirang speakers yan? ;D
kinyo,
now you can have your dream come true!!!
jojo,
splendid!!! my compliments!!! DIY is the way to go, because with DIY we are masters of our own creations, we are not limited to what's being peddled, we can choose the quality and quantity of our parts, and when we come up with a finished job, it is something we can call our own, and truly this give more satisfaction than any other thing that money can buy!!! Long LIVE Pinoy DIY!!!
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kinyo,
Wala pa naman syang nasisirang speaker (buti na lang), but the sound is really something. Your dreams can come true, you know. I only built one of this but did you know that joan2 built about 30 of these? That means we can help you with that dream, besides, other people helped me in mine.
JojoD
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joan2,
Thanks my friend! I agree about being masters of our art when it comes to diy. Truly something that money cannot buy!
JojoD
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rmpmla,
Your current trafo will complicate things due to the added voltage regulator needed that will also dissipate heat. Just buy a 24-0-24 trafo for your gainclone. BTW, you did a very nice breadboarding there.
TIP: Save your 36-0-36 for a leach maybe? ;D
JojoD
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jojo,
maybe it will be good if we can have MGR, Nhaldy, C3PO, and Muzikluv join us here!!! their inputs will certeinly be usefull....we are fortunate to have the internet, it is very easy to get support now, than say ten years ago...and free samples to go along....
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joan2,
Thanks my friend! I agree about being masters of our art when it comes to diy. Truly something that money cannot buy!
JojoD
jojo,
lest we be misunderstood, what i mean is that we are masters of our own creations, of the amps that we build!!!, i am still learning, and going to diyadio.com made me realize how little i know, that site is God's gift to diy'ers like us!!!
Kinyo,
if you want to have a look see of one of my creations, you can come to the house, it's a leach double-barrelled amp, housed in an all black, aluminum chassis and front panels....too bad i do not have a digicam to take pictures!!!!
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jojo,
lest we be misunderstood, what i mean is that we are masters of our own creations, of the amps that we build!!!, i am still learning, and going to diyadio.com made me realize how little i know, that site is God's gift to diy'ers like us!!!
Exactly what I meant! Hahaha... Like you, I am still a student, keep on learning new things day by day.
About our fellow pinoy diy in the net, I definitely agree that they can provide useful insights in our projects. I hope they can join us here! ;)
JojoD
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Guys!
Up na yun low pass filter design ko! You can use it with your gainclones for a powered sub project! 8)
http://www.geocities.com/jojod818/
Enjoy!
JojoD
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Jojo and joan2,
Thank you for encouraging me to build a Leach amp. Yup, I would need help on the PCB. Kung meron kayong pwedeng ibenta sa akin, I'd sure build one, mono muna para sa active subwoofer, para hindi masayang itong subwoofer kit ko. But I'd be willing to buy more PCB's for future projects. Nasa probins ako kaya medyo mahirap hanapin ang mga piyesa, e.g., transistors. You might as well reserve some for me if you have them too. I'll probably spend a few days in Manila for xmas, so it'll be a good time to meet you guys.
For now, hinihintay kong dumating yung OPA541 from TI, para sa bass shaker ko. Meron na akong traffo, so as soon as it arrives, it will only be a matter of a few days before the amp is realized.
Thanks in advance! ;D
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Mika,
I have uploaded the schematics for the 541 and the 549 on my site. Still no pictures though, maybe later. :(
Go here: http://www.geocities.com/jojod818/
JojoD
thank you very much JojoD :) ;)
nice work done on your website, i'm sure you'll get many hits in no time. a welcome reference for future GC builders.
i bet you have many other projects up your sleeves... care to post a preamp for the GC? ;) :D :) :o
more power to all diy'ers
... not so much though, that we'll get electrocuted ;D
8)
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i bet you have many other projects up your sleeves... care to post a preamp for the GC?
I'll try to post as many as I can. Sadly, I use Coreldraw for designing pcbs and schematics. I have Protel and Orcad but can't learn the darn thing. >:( But I will upload more projects that contains locally available parts and complete plans.
more power to all diy'ers
... not so much though, that we'll get electrocuted
LOL
JojoD
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you actually have the opportunity to eliminate ripples on the rails if you add a series pass voltage regulator for each rail. the regulator will drop the voltage to a safe level at the same time keep the voltage steady (no ripples if designed properly to handle the load). added circuitry ito but it is one option to solve your problem. the regulator will use power transistors too so heatsink is also required.
the easy route is simply to replace the transformer with lower voltage output, say 24-0-24, 3A for a single OPA541 :)
mukhang magiging complicated.
buy na lang ako ng 24v-0-24 transformer :)
thanks,
rmpmla
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you need a +40/-40 volts rails, so the only way you can use that is to buid a voltage regulator to bring down the rails to proper voltages...or you can change the transformer to one that has the proper ac voltages, 24-0-24 is a safe figure, it will give a +/-36 volts at no load, suitable for an opa541 or an lmm3886 if you decide to change it later on....take note of the windings of the original transformer, then you have another one made to your specification....the transformer that you will take out from your existing amps can be used for a leach amp later on, jojo and i will help you if you decide on it....
rmpmla,
Your current trafo will complicate things due to the added voltage regulator needed that will also dissipate heat. Just buy a 24-0-24 trafo for your gainclone. BTW, you did a very nice breadboarding there.
TIP: Save your 36-0-36 for a leach maybe? ;D
JojoD
kinyo, joan2,JojoD818,
Thanks :)
i will get a 24-0-24 transformer :)
rmpmla,
BTW, you did a very nice breadboarding there.
JojoD
JojoD, thanks.
tinamad na ko na gumawa ng pcb ;D ( although i bought a PCB and ferric cholride ). but once i test this one will make a PCB as per your e-mailed pattern.
rmpmla
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mukhang magiging complicated.
buy na lang ako ng 24v-0-24 transformer :)
thanks,
rmpmla
before you buy the transformer, please check if there are other secondary windings, if there are, what are the voltages, if none, then simple replacement can be done.....
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Hey JojoD818 great pics of GCs and leach amp. Really nice work! I envy you!
Ok I finally got my tube IGC working--at least half of it. When I first turned it on, there was a slight hum on one channel and all hum on the other. After hours of tweaking my grounding config, I finally got the right channel to work totally hum free--the solution was simple: ground the case which was also the heatsink to my signal star. Voila! My wiring is P2P--it looks decidedly untidy because of the ground tweaking.
Now the other channel still won't work--I hear the music for 3 seconds before it goes out. The problem could either be the chip or the tube. I thought it was the chip because this is the one which had pins 1 and 7 resoldered after I broke them ;D) . It turns out its the other half of the tube that's not functioning because when I bypassed the tube, all the hum is gone and I was able to play music. The right channel plays ok with the tube.
I was able to compare for a few minutes the difference in the sound and the tubed version definitely (here the difference is so noticeable) more open sounding. It just has more sparkle. But my impression is that its still a little bit bright for my taste. At extremely high volumes the sound gets distorted--I don't know if its the amp becoming unstable or the AIWA test speakers I'm using. I'm using a 0.001 uf film cap from inverting input to ground as my LPF. I have yet to replace my buffer supply transformer. When I have the tube replaced tonight, I'll give my subjective impressions over the next couple of days about the sound.
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When I turn on the amp with the speaker connected, I get rumbling sounds but not very loud which I think is the sound of the tube stabilizing. This lasts for just 4 seconds. Is this safe for my speakers?
If not, is there anyway I can delay the power on for the chip. I've searched the Internet and there's this timer IC 555 but I don't know how to wire it up. I've looked at the LM555 datasheet but I don't understand it. Any suggestions? Thanks.
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Garp,
I forgot what chip you are using but if it has a mute pin then you can use that to delay the turn on of the gc your using. If it doesnt, there is another way of delaying the connection of the speakers to the gc by using relays. That is if it is ok with you because there are guys who hate relays. ;D You can use an LM555 and configure it as a monostable and compute how many seconds delay you need and connect the output to a gen. purpose npn transistor that energizes the relay.
I have a relay driven delay switch that doesn't require an LM555, just a capacitor, a diode, a relay, a transistor, and a bunch of resistors. :D
JojoD
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Garp,
I'll try and draw it asap so that you can see what I'm talking about.
JojoD
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Thanks JojoD818--look forward to it! Im using an Lm3875 so no mute chip here. I think though I much prefer a relay at the power supply end vs. at the speaker connection end. :)
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garp,
may i know what tube you used, did you wire it as a cathode follower? and what voltages did you use....if you want a speaker time delay relay, u can use a simple transistor, an npn with a 1amp Ic rating will do,like a 2sc1061 then you can wire a 470k in series with a 100uf/6.3 volts electrolytic, the junction of these you can wire a 1k ohm to connect to the base of the npn, then emiter connects to ground, the collector to the relay, then the other end of the 470k and the relay coil to the Vcc, the other end of the electrolytic cap connects to ground, now you can have a speaker time delay switch....
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Jojo and joan2,
Thank you for encouraging me to build a Leach amp. Yup, I would need help on the PCB. Kung meron kayong pwedeng ibenta sa akin, I'd sure build one, mono muna para sa active subwoofer, para hindi masayang itong subwoofer kit ko. But I'd be willing to buy more PCB's for future projects. Nasa probins ako kaya medyo mahirap hanapin ang mga piyesa, e.g., transistors. You might as well reserve some for me if you have them too. I'll probably spend a few days in Manila for xmas, so it'll be a good time to meet you guys.
For now, hinihintay kong dumating yung OPA541 from TI, para sa bass shaker ko. Meron na akong traffo, so as soon as it arrives, it will only be a matter of a few days before the amp is realized.
Thanks in advance! ;D
kinyo,
i have 8 boards already stuffed with parts, it is for the leach double barrelled amps with 250w ave. continous power inot 8 ohms, jojo i think has the leach version 4.5 lo-tim amp...send me an email and i will tell you how to get parts for free!!
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garp,
may i know what tube you used, did you wire it as a cathode follower? and what voltages did you use....if you want a speaker time delay relay, u can use a simple transistor, an npn with a 1amp Ic rating will do,like a 2sc1061 then you can wire a 470k in series with a 100uf/6.3 volts electrolytic, the junction of these you can wire a 1k ohm to connect to the base of the npn, then emiter connects to ground, the collector to the relay, then the other end of the 470k and the relay coil to the Vcc, the other end of the electrolytic cap connects to ground, now you can have a speaker time delay switch....
Hi Joan2. I used a Jan Philips 6922--although will be testing tonight a 6h23. I think its a simple cathode follower--don't know what that is--just followed Joe Rasmussen's design. My buffer is at about +/-33VDC and filaments at around 5.8VDC. I used a 7806 regulator. I'm still using a 12-0-12 trafo which I plan to replace soon.
Thanks for the relay suggestion...but I have to apologize because I can't follow you--if have any schematic I can look at? ;D
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One more question, I measured the offset at the ouput but I see a negative offset of about 2mv on the right channel (the non-functioning left channel has a 25V offset!) does this mean my output terminals should be reversed?
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Garp,
What joan2 said is what I have in mind too. But if you don't like a relay on your speakers, the same principle can delay the power to your gainclones. I'll draw a schematic tonight.
JojoD
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Garp,
Where do I send the schematic so it can be posted here?
JojoD
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JojoD818, thanks alot for this. Can you email it to me instead and ill just find a way to have it hosted so it can be posted here. Will Pm you my email.
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Garp,
Just finished the schematic. I'll check my email.
JojoD
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Garp,
I have not received any pm from you, please send me your email so I can send you the schematics.
JojoD
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One more question, I measured the offset at the ouput but I see a negative offset of about 2mv on the right channel (the non-functioning left channel has a 25V offset!) does this mean my output terminals should be reversed?
garp,
a 25 volt offset means that you have a wrong connection somewhere or the -rail may not be properly connected, check you wirings again, you can use the other channel with the 2mv offset as refference!!!
the 6922 and the 6h23 are equivalents, i looked at the plate characteristics and at 0 grid and plate volts of 66v you should get a plate current of about 15mA or so, did you use a blocking cap at the cathode?
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Joan2,
Gud pm, I would like to take the gainclone thing to the next level, a bridge/parallel combo. However AN-1192 App Note says that I need 0.1ohms 0.1% 5W resistors between the four outputs of the chips. I have searched hi and lo for such a resistor with no avail. Would it matter if I use the readily available 0.1ohm 5w resistor found in raon? I also plan to use 5% carbon compo resistor for the feedback instead of the recommended 1% types. I hope this baby works! Any comments, violent suggestions? (Just kidding) ;D
JojoD
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Joan2,
Gud pm, I would like to take the gainclone thing to the next level, a bridge/parallel combo. However AN-1192 App Note says that I need 0.1ohms 0.1% 5W resistors between the four outputs of the chips. I have searched hi and lo for such a resistor with no avail. Would it matter if I use the readily available 0.1ohm 5w resistor found in raon? I also plan to use 5% carbon compo resistor for the feedback instead of the recommended 1% types. I hope this baby works! Any comments, violent suggestions? (Just kidding) ;D
JojoD
jojo,
no problem, you can use that, in fact you can also use 0.22 ohm/5watt resistor, they are for ballasting and needed because not all chips have the same input offset characteristic, as to the carbon film resistors, i see no problem using them, it is cheap and readily available, metal films are used on low-level circuits such as phono/mic preamps, where the low noise characteristic of the metal film resistors can be put to good use...if you want you can screen your resistors so that you can get good matching using your dmm...i seldom do this.
garp,
i forgot to metion, never connect a peaker to an output that has a 25volt offset, it will fry your speaker, for testing, use your cheapo ones first, if everything is fine then you may connect your regular speakers...a voltage offset of up to 100mv should not be cause for concern....
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joan2,
I can do the screening to get a good match with the resistors. I have done this in my leach amp, a little patience is all it takes though. ;D
Garp,
What's up?
JojoD
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joan2,
I can do the screening to get a good match with the resistors. I have done this in my leach amp, a little patience is all it takes though. ;D
Garp,
What's up?
JojoD
and a lot of resistors too!!
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Yup,
I have a lot of them, it's cheaper to buy a bunch of them than per piece. ;D
Wish me luck!
(DRV134 is on it's way...)
JojoD
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good luck!!! and as always, safety first!!!
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Guys,
Just finished the pcb for the other 2 channel gc. I'll drill them later. I plan to use my existing 2 channel and parallel it then my new 2 channel (in parallel also) and the two paralleled amps will be fed from a drv134 expected soon.
JojoD
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JojoD818, sorry I was offline whole day yesterday. Can I PM you my email again for the delay schematic? But right now I need you guys to help me sort out my problem.
Like the last time, its only one channel that's not working. The other channel works great with the tube connected. Here's what I did:
1) Replaced with a brand new JAN Philips 6922--got the same problem. Played clear music for 3 seconds before it gave way to total hum.
2) Replaced with a 6h23. This time though it played and the music was loud and clear. I thought this was it but the temperature rose quickly and in 10 minutes it started to distort and the volume was reduced.
3) Bypassed the tube on the problematic channel so its just a plain IGC--played clearly and did not get hot. It seemed stable. No hum no noise.
4) I've already replaced my transfo, double checked resistor values. The grounding config are the same for each channel. They share the same chip supply(toroid 160Va), buffer supply(3 amp 24-0-24) and filament (5.8V regulated). My chip is isolated from the heat sink.
Here's what I plan to do next:
1) Rewire the damn thing--making sure that wires which do the same things have exactly equal lenghts.
2) Replace the feedback resistor with a new one--I've already replaced some resistors and and the film cap.
3) connect the ground of my input (RCA) directly to ground of pot and not to signal star ground.
Any other ideas?
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JojoD818,
I'm also thinking that I damaged my chip LM3875--you've worked on the OPA541/OPA549, can that be a drop-in replacement for the 3875? I just want to know before I try it.
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garp,
it will be hard to troubleshoot based on your description alone, if you have some pics that we can look at, then we may be able to help, i have some questions?
1. is your other igc that had a 25v at out ok already?
2. are you able to paly music on both igc's without the tube buffers?
if the answers to the above are yes, then you have grounding problems, that's why the humming.
3) connect the ground of my input (RCA) directly to ground of pot and not to signal star ground.
yes, but you still have to connect that end of the pot to ground....
the opa541/549 are not exactly drop-in replacements as they have different pinouts, but working voltages are the same, please check the bb/ti datasheets...
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garp,
it will be hard to troubleshoot based on your description alone, if you have some pics that we can look at, then we may be able to help, i have some questions?
1. is your other igc that had a 25v at out ok already?
2. are you able to paly music on both igc's without the tube buffers?
if the answers to the above are yes, then you have grounding problems, that's why the humming.yes, but you still have to connect that end of the pot to ground....
the opa541/549 are not exactly drop-in replacements as they have different pinouts, but working voltages are the same, please check the bb/ti datasheets...
Will try to get you pics tomorrow.
The one with a 25V out plays well--no hum and doesnt get hot--without the tube. I haven't measured the offset w/o the tube but will do that tonight.
I have yet to try to play the IGC both channels w/o the buffer--will do tonight and report my findings tomorrow
Right now my input ground connects to the signal ground star directly and the ground from the pot to the signal ground star--I dunno if it will make a difference if I connect the input ground to the pot and then a wire from pot ground to signal star.
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Garp,
Pin configuration of the OPA549 and OPA541 are different so a drop-in replacement is not possible even with an LM3875.
JojoD
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Garp,
Just sent you the schematic.
JojoD
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Garp,
Just sent you the schematic.
JojoD
Thanks very much! I actually saw a power-on delay kit at Alexan but its quite pricey at P400+ so I decided not to buy it.
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(http://us.f1f.yahoofs.com/bc/4e7174bf/bc/Delay/delay2.gif?bfEJIq_AYbuOqOsT)
Jojod, newbie questions sorry--so I connect my wires in the relay--does it matter which pair of relay contacts? I see there are two pairs of them. So both wires--neg and pos--connect to the relay right?
Can put this delay circuit between the rectifier and the transformer secondary outs?
What amp rating for the relay? is the one you used--Lynnks is it?--ok for this one?
Is the 12VDC max or is there are an acceptable range? Can I use the one for the tube filament at 6V to power this one?
Do you have a formula for the delay time? I just need 15-20 seconds delay. But if you don't have it I guess Ill just have to experiment.
Again, big thanks to you.
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garp,
you connect the 'hot' speaker wire, meaning the wire from the output pin to one side of the normally open contact of the relay and the other side to the speaker terminal, do this with the other channel, the speaker negatives go to the central ground point and is not connected to the relay...SMG sells speaker protector relay kit, you can check them out, could be cheaper than alexan's....
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Garp,
The relay must have a 12V coil and 5A contacts at least. But if you can find a 10A much better. The 12V supply is for the relay, if you have a 6VDC voltage source, you must use a 6V relay with the same contact rating.
As to where you put it, joan2 suggests you use the relay contacts for switching the speakers but you mentioned somewhere that you rather put it between the supply rails. You have two choices, after the transformer or after the bridge. If you choose after the bridge, don't forget that the wires are already polarized (+ and -) but if you choose after the transformer and before going to the bridge diode, the wires coming in and out of the relay are interchangeable.
A third option is if you use a separate transformer for your gainclones, this time you only need an SPST relay but BEWARE, this option involves MAINS WIRING. If you don't know how to do it, DON"T! But if you do, that would be easier. If I were you, that's what I will do. ;D
As for the formula, I don't have it, the 33K gives about 2 secs while I haven't tested it on a higher resistance. If you have junk capacitors in the 25V-50V range and about 220uf or 330uf or even a 470uf you can use that. Look for junk npn transistor and just buy the relay. The LYNNK's brand is a good brand, but any decent relay should suffice, hell you can even use Bosch automotive relays to make it cheap. ;D DPDT relays with 5A cost about 95-100 pesos.
SMG in raon sells a series 6 volts relay and may not be a versatile one. I have one here. Joan2 is correct, they are much cheaper than alexan's.
If you have other questions, just fire away!
BTW, be extra careful in mains wiring. ;) electricity is for circuits, not for humans.
JojoD
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garp,
a 10amp dpdt, 12volt relay cost 95 at deeco, as for the time delay values, the rule of thumb is the higher the resistance and or capacitance, the bigger the time constant(R x C)......the longer the delay....
can you post the complete specs of your new torroid, what are the secondary voltages, what are the currents, so we can advise you how to arrange you power supply more efficiently!!!
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can you post the complete specs of your new torroid, what are the secondary voltages, what are the currents, so we can advise you how to arrange you power supply more efficiently!!!
Joan2, JojoD818,
I have a bigger problem that I'm too embarassed to post here (its about my equipment but not that other equipment) so I just sent you and JojoD818 a PM about it.
Here's My PS:
As for the toroid, its what I used for the prototype. Its a Nuvotem-Talema 160VA 18-0,18-0 dual secondaries up to 4.+ amp. Each secondary is connected to MUR860 bridge so 2 bridges total per trafo. I have 0.1 MKT caps connected before and after the rectifiers.
My buffer supply uses a trafo from SMG, 3amp 24-0-24. I use a single MUR860 bridge followed by a CRC filter network (1000uf-220ohm-120uf) and than a 1uf film cap.
My filament uses a 1 amp 12-0-12. I have about 200+uf electro and 0.1uf film before the 7806 regulator and .1 uf film plus 140uf after the regulator.
I'll post pictures as soon as I can.
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Garp,
I agree with joan2, an efficient psu is a big plus on your system. I haven't checked my email but to be embarassed with a system you yourself have is what diy is here for. I mean, a whimpy system has a better chance of being a better system in the hands of diyers, remember that.
For example, I onced was given a "pamana", a Fisher 25 watts amp. It wasn't much but through improvement it was a winner in my book.
Cheers,
JojoD
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garp,
looks like you have a collection of traffo's there, is your torroid potted or not? if is not then very easy for us to wind additional coils for your tube buffers and filament supply, this way you will only have one traffo, the buffer tube will not consume more than 2watts you filaments about 3 watts, but owing that it is regulated, you will probably need to tap at least 10 watts from your torroid, so if that torroid has that big hole in the middle, you are in luck man...very easy to add windings, a #28 magnet wire for your +/-35 tube buffer supply and a #20 for you filament supply will do it!!!!
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Hi guys,
Almost finished with my second prototype of the parallel/bridge combo. I will post observations asap.
JojoD
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JojoD818,
In your website, I saw a speaker protection circuit. Can you share the schematic or point to me where i can find it?
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GregGC,
Try this: http://sound.westhost.com/project33.htm
JojoD
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Guys,
It's working! ;D
Parallel/Bridge is like Master Yoda, powerful!
JojoD
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Ok finally isolated my GC problem. Its not the tube, not the circuit, and not the chip as I initially thought. It's my DC blocking capacitor that's faulty. A basic GC can work withouht it but a tubed GC cannot. Everything's ok now. I get a 300mv offset at startup and when the tube stabilizes I get 30-20mv on the lm3875 channel.
I swapped the opa541 for LM3875 in the other channel using the same circuit ( pin 8 connected to Vo; no current limiting resistor). I MUCH prefer the LM3875. Even if I used a P15 peso DC blocking cap on the LM3875 vs. the film cap on the OPA541, the LM sounds rich and more delicate in the highs. But I think the OPA541 has a bit of an edge in the bass. In fairness, however, to OPA541 the circuit was designed with an LM3875 in mind. Now I can work on that delay circuit.
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I need somebody's help. Where and how much can I buy LM1875? thanks!
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LM1875 is widely available in Raon--try newport. You can get for P90+ each.
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Garp,
Nice to hear that your circuit is running well, now that's diy stuff!
BTW, can you post known chipamps prices that are locally available?
Example:
LM1875=P90+
LM3875=?
LM3886=?
What street is newport at, I can't remember if I've been there before? ::)
JojoD
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LM1875 is widely available in Raon--try newport. You can get for P90+ each.
Lots of thanks!
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JojoD818,
LM1875=90+ (Newport etc., sorry dunno street names)
LM3875=P700 (not widely available but last time I checked 3 weeks ago Lamson has it)
LM3886=about 200+ at Newport I think
TDA7293/94=P200+; I'm guessing this is availble in Raon because 2 of the 4 stores I go to here in Cavite have them. It's really a bargain because these sell for P700 at Farnell. Maybe the're fakes?
TDA1541A --DIY DAC anyone? a little over P100 here in Cavite; dunno in Raon
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I need somebody's help. Where and how much can I buy LM1875? thanks!
welcome to the thread!!! lm3886 can be bought at newport electronics for 275 if you want more power!!!!
if you want free samples of the BB/TI Op541/549 you can go to www.ti.com (http://www.ti.com)
can i interest you with a Hiraga Class A amps?
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Garp,
I have tried that 1514A from Philips. Nice sounding chip.
Thanks for the info.
JojoD
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welcome to the thread!!! lm3886 can be bought at newport electronics for 275 if you want more power!!!!
if you want free samples of the BB/TI Op541/549 you can go to www.ti.com (http://www.ti.com)
can i interest you with a Hiraga Class A amps?
Sir, what's special about this amp other than being classA?
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Sir, what's special about this amp other than being classA?
it' simplicity i guess....
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another gainclone site you may want to see:http://www.ampchipdiy.com/phpBB2/viewforum.php?f=2 (http://www.ampchipdiy.com/phpBB2/viewforum.php?f=2)
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Sometimes the simpliest things are the best things...
I have just uploaded my torture tested bridge parallel gc here: http://www.geocities.com/jojod818/index.html
JojoD
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joan2,
can you please send me a schematic of a class-a amp with transistors for output devices? 10-20W amp will do.
[email protected]
thanks,
JojoD
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jojo,
here is the link:http://www.bonavolta.ch/hobby/fr/audio/monster.htm (http://www.bonavolta.ch/hobby/fr/audio/monster.htm) or this one:http://www.gmweb.btinternet.co.uk/index.htm (http://www.gmweb.btinternet.co.uk/index.htm)
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joan2,
Are the components locally available? Any substitution done?
JojoD
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jojo,
i have not done any classA amps yet, all i did were all classAB, but with the samples that we got from onsemi, we can build one, with the exception of the jfets, the transistors can be replaced with onsemi parts, you may google the originals and compare their characteristics with the onsemi parts....
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joan2,
well, that's what I really had in mind. I mean, to substitute parts that I have except for the jfets. Thanks anyway for the data.
JojoD
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Guys,
:( It's sad but ON Semi has stopped it's samples program, probably due to cost cutting or even abuse....
JojoD
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that's bad news!! my last order was in september....
anyway, here is another one:http://www.bonavolta.ch/hobby/en/audio/hir20.htm (http://www.bonavolta.ch/hobby/en/audio/hir20.htm)
if you notice, voltages used are +/-12 and +/-24, meaning car batteries may be used so that ac rectified power borned problems are left out altogether!!!
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What about this: JLH Class A 10-Watt designed for highly capacitive loads and impedance down to 2 ohms.
http://www.tcaas.btinternet.co.uk/jlhesl.htm (http://www.tcaas.btinternet.co.uk/jlhesl.htm)
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Guys,
Maybe a "DIY Class A amp anyone" title for a thread is in order... ;D
JojoD
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Yet another chip amp derivative here. Interesting review of nOrh Le Amp I. It uses TDA7294 that's available locally for a little over P200 a piece. Not to fuel any debate over SS vs. tubes, there's a comparison here between Le Amp and Antique Sound's K2003 SET integrated amp.
http://www.tnt-audio.com/ampli/norhleamp_e.html (http://www.tnt-audio.com/ampli/norhleamp_e.html)
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Guys,
Maybe a "DIY Class A amp anyone" title for a thread is in order... ;D
JojoD
please go ahead and do it!!!
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Yet another chip amp derivative here. Interesting review of nOrh Le Amp I. It uses TDA7294 that's available locally for a little over P200 a piece. Not to fuel any debate over SS vs. tubes, there's a comparison here between Le Amp and Antique Sound's K2003 SET integrated amp.
http://www.tnt-audio.com/ampli/norhleamp_e.html (http://www.tnt-audio.com/ampli/norhleamp_e.html)
better take this with a grain of salt, but anyway,
this just goes to show we can have a tube-like performace at a non-tube cost, shouldn't we be thankfull for that?
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Yet another chip amp derivative here. Interesting review of nOrh Le Amp I. It uses TDA7294 that's available locally for a little over P200 a piece. Not to fuel any debate over SS vs. tubes, there's a comparison here between Le Amp and Antique Sound's K2003 SET integrated amp.
http://www.tnt-audio.com/ampli/norhleamp_e.html (http://www.tnt-audio.com/ampli/norhleamp_e.html)
Thanks garp for the noted TDA7294. Where can I buy this stuff for a little over P200?
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Is there a change in schematics by using TDATDA7294 instead of LM1875? Where can i get the schematics?
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Is there a change in schematics by using TDATDA7294 instead of LM1875? Where can i get the schematics?
pin-out are not the same...http://www.google.com/search?q=tda7294&btnG=Google+Search&hl=en&lr=&ie=UTF-8&oe=UTF-8 (http://www.google.com/search?q=tda7294&btnG=Google+Search&hl=en&lr=&ie=UTF-8&oe=UTF-8)
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TDA7294 is made by SGS Thomson, they also make other chipamps that I have a chance to build. I built 33 pcs of TDA2050, 14 pcs of TDA2030A to be exact. ;D
Try it! They are dead cheap and reliable too. Just put them in a huge heatsink and they'll be happy, and so will you.
JojoD
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Thanks garp for the noted TDA7294. Where can I buy this stuff for a little over P200?
I'm assuming they have it in Raon because 2 local stores here in Cavite have them. And they get all their stuff from Raon.
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Here are some 7294 pics & schematics :
http://www.keces.com.tw/~korping/diyproject/audiodiy/D0209001/D0209001.htm (http://www.keces.com.tw/~korping/diyproject/audiodiy/D0209001/D0209001.htm)
http://www.keces.com.tw/~korping/diyproject/audiodiy/D0207004/D0207004.htm (http://www.keces.com.tw/~korping/diyproject/audiodiy/D0207004/D0207004.htm)
http://www.keces.com.tw/~korping/diyproject/audiodiy/D0305005/D0305005.htm (http://www.keces.com.tw/~korping/diyproject/audiodiy/D0305005/D0305005.htm)
http://www.keces.com.tw/~korping/diyproject/audiodiy/D0208001/D0208001.htm
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Hi guys,
Almost finished revising my pcbs for ss amps, leach amp low tim, speaker delay, chipamps, etc. I plan to have our pcb manufacturer to make a few of each for me and if your interested too. Nothing special, pre-drilled, coated with anti-oxidant, no parts stencil, no solder resist.
JojoD
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Garp!
I love those heatsinks!!! Shame they are not available locally. >:(
I once read a metal fabricator there in Cavite that makes various heatsinks. They are located in some industrial complex or something. I wish you know about them.
JojoD
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Sorry, I'd be interested to know where they are too. But in the pics, aren't those the same looking as what's sold at Alexan? They have lots of funky sinks at Farnell but they're not cheap--too bad.
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Hi guys,
Almost finished revising my pcbs for ss amps, leach amp low tim, speaker delay, chipamps, etc. I plan to have our pcb manufacturer to make a few of each for me and if your interested too. Nothing special, pre-drilled, coated with anti-oxidant, no parts stencil, no solder resist.
JojoD
Definitely interested in the speaker delay PCB ;D (BTW I've already replaced my blown speaker drivers--glad they're not expensive) and Leach PCB. Ehem what's Low TIM? Let us know how it goes. Thanks.
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jojo,
i'm also interested in the leach low tim pcb.
tnx.
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Garp,
Low Transient Inter-Modulation (TIM) Distortion... aka Low TIM. ;D
Homer,
Will tell you when they are ready. I just need an idea on how many must be made. Also planning on manufacturing pcb for the Leach Super Amp. ;)
JojoD
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i got in touch with Hooven Comalco, a local aluminum extrusion company located in Cainta Rizal, they can make extrusions based on costumers' design, but the die cost is around 50k and another 50k for minimum order, big bucks!!! so our best bet is the surplus junk shops selling them, we used to go as far as Cabanglan in Zambales, and in Angeles in Pampanga, for alumunim h sinks, don't know tha situation now...there is one dealer or surplus aluminum heatsinks that came from EPZA plants, this one is located in Ususan in Taguig, i bought just recently 2 pcs hs that can accomodate 4 gainclone chips, this hs is pre drilled!!!! cost is 60 without the fan, 100 if with fan....
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joan2,
I wish you can show us pics...drool.... ;D
I also wish that a lot of heatsinks can be bought locally. :'(
JojoD
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jojo,
mang oca, the shop owner, doesn't know me by name, i am but one of the many who frequents his shop in search of cheap but first class parts...you may contact him thru this number....6270743....
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joan2,
Thanks for the intel, I will call them soon. I am currently finishing up the chassis for my 150W opamp based amp.
Thanks,
JojoD
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Guys,
Just finished my new 150W opamp based power amp, and another one still on going for a friend's front channel.
So how's everybody's gainclone? My bridge/parallel is still working! ;D Happily powering my sub at the moment.
JojoD
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So how's everybody's gainclone? My bridge/parallel is still working! ;D Happily powering my sub at the moment.
JojoD
Glad to hear your bridge is working great. While waiting for my LM3875 to arrive (one channel runs on LM3875 so in the meantime I use the other channel to test chips), I tried putting in LM1875. Honestly can't tell the difference in the sound between 1875 and 3875. The OPA541 distorts at high frequency so I guess my circuit does not apply( mad k I think of diyaudio experiences the same distortion). I tried the SK1875 which supposedly is the one used for the Gaincard--sounds bad. Problem however is that when I have both 1875 and 3875 loaded, I get a ground loop. If only one of them is loaded, it plays great. Ill have dual mono supplies so this won't really be a problem later.
I've finished my delay circuit and I get a 23s delay. Connected it to the wire between the mains and primary of the toroid. Now what I really need is a speaker protection circuit because although I don't hear anymore the tube equalizing, its when I power on the source while my amps is on and connected that I get a loud snap.
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Garp,
Nice to hear that your setup is ok now. Where did you ordered the LM3875? That chip is really something eh!
JojoD
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Garp,
Nice to hear that your setup is ok now. Where did you ordered the LM3875? That chip is really something eh!
JojoD
JojoD,
Got it from Access Frontiers at P430+. RS also has them but a bit more expensive. Both stores though offer great service.
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Garp,
Thanks for the info!
JojoD
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jojo,
would you like to join us at www.tipidpc.com? you could regale them with your gainclones for pc sound system...this is a community of pc enthusiasts who espouse the 'biggest bang for the buck' philisophy....
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I would love that tony. However, I am already a member of that site too. I also saw you at Pinoy PC Network! I was very active there some 3 years ago... :D
It's a small world afterall...
I'll check back at tipidpc.com, maybe I can sell some power amps or gainclones? Of course the chips will be bought locally... ;D
JojoD
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Jojo, sent you PM...
:)
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Leiko,
Just sent you a pm too. ;D
JojoD
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I would love that tony. However, I am already a member of that site too. I also saw you at Pinoy PC Network! I was very active there some 3 years ago... :D
It's a small world afterall...
I'll check back at tipidpc.com, maybe I can sell some power amps or gainclones? Of course the chips will be bought locally... ;D
JojoD
i like it when you call my by my name, anyway TPC is down at the moment, will be migrating to a dedicated server and getting an 800gb bandwith, will be up by saturday i was told...
they will be coming up with a TipidCelphone in the future...who knows maybe a TipidAudio too for those cheap but good audio gears!!!!
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joan2,
yep yep yep! a tipidAudio is a good idea! That would expose us to new & cheap gears! Yahoo!
JojoD
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Fastback,
I hope you find this thread...now on with the LM12. I just studied (again) the datasheet and I also found the magazine "Electronic Enthusiasts Issue 55" that contains the project using the LM12C power opamp. As far as the chip is concerned, we will only need the datasheet to build a prototype for this gainclone.
Tony, please do jump in for power supply recommendations on this chip.
If I remember it right, this chip costs almost 1k pesos. now that is enough to make diy enthusiasts like us to stay away from them chips. But since Fastback has a bunch of them, let's help him make some use for that chip.
Fastback, a bridge/parallel LM12C can really be a monster amp and an excellent sub amplifier!
JojoD
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the lm12 can do 100watts into 4ohm if i am not mistaken, whereas the lm3886 is rated for 60watts....
there was an article published in 'Elecrtonincs Magazine' a few years back it included the pcb layout and you have a choice of 2 types psu, one is an smps for car operation, the other a conventional one using torroid traffo for home use...
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There's been a lot of talk about Non-Inverted config lately and some of those who have tried it like Peter Daniel swears by the superiority of NIGC over IGC. I wanted to hear for myself so I hastily put together a NIGC. I just used LM1875 for this one and junk parts (P16 peso caps). I tried though to minimize the signal and grounds parts as best as I could. I like the sound well enough to improve this and use better quality parts in the next iteration. The PS is what I use for the tube buffered IGC. Size of amp is just slightly bigger than my hand.
NIGC using mostly same resistor/cap values as the Gaincard. No DC coupling cap, no zobel. DC offset at 95mv--pls tell me that's acceptable.
(http://www16.brinkster.com/agenota/nigc.jpg)
PS ( the EIs are for the tubes, still missing one toroid, delay circuit on the left side courtesy of Jojo and Joan2)
(http://www16.brinkster.com/agenota/powersupply.jpg)
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hi
im almost done with my inverted lm3875 clone. im just looking for a suitable casing for it. i have a spare sheet of hardwood here, is that a good material for the case?
garp, what kind of pot did you use?and what kind of knob did you use?
btw, jojo what brand of capacitors do you use in your amps?
i'm also planning to build a full range speaker based on the 8" dai-ich which uses the twqp design. this sounds close to a lowther daw.
mang tony, you told me before that you were also planning to build some speakers. can you share to me your ideas.
thanks!
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hi
im almost done with my inverted lm3875 clone. im just looking for a suitable casing for it. i have a spare sheet of hardwood here, is that a good material for the case?
garp, what kind of pot did you use?and what kind of knob did you use?
thanks!
for the NIGC just used cheap pots available everywhere. But in the tubed GC will be using a 12-step attenuator using 2 Lorlin switches. The knob is just plastic commonly available everywhere about P25 each I think. Eleshop has some nice knobs--they have solid aluminum knobs that's quite heavy going for P20. Or you can just get Vishay P11 at Farnell or Alps but they're not cheap. I just used hardwood for the front and back panel.
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moonshow,
I use Elna or CapXon caps whenever I can, but if budget is kinda tight, I find the taiwan "Jackon" brand to be the best among the cheap ones.
JojoD
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moonshow, can you enlighten me as to what a twqp design is? I am seriously planning on a MTM Classic tower design which uses 2 pcs 8" woofer and a tweeter. I just listened to one of dai-ichi MTMs and was surprised at the sound. I want to build this one instead of buying a ready made one.
JojoD
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i recentrly found out that a twqp is a form of folded voigt type of enclosure which only uses 1 full range driver. i had communicated with another person from the wired state forum regarding this. i'll just quote his email here.
"This project is still in its developmental stage, although a few individuals from the audiophile group have requested me for the detailed design, which I humbly obliged. Explaining this in few short sentences will be quite hard as it took me 2 years, 4 cabinet designs and 5 driver pairs just to perfect the adjustments I made on one set of drivers.
The one posted on the thread was the latest geometry (folded voigt) for the Dai-1chi driver. But I'm presently developing another geometry just to test which geometry will suite the driver.
Just to give you an idea, the dai-1chi driver I used is an 8" full range driver with a frequency response between 50 - 18000 hz. It has an impedance rating of 8 ohms and an SPL of 90 dB. With my cabinet geometry, I was able to bring down the cutoff almost 20 Hz, and the SPL increased to 94 dB. I have three cabinet versions currently running: A classic straight pipe, and inverted straight pipe, and a folded pipe. I use vacuum tube amplifiers in all three speaker sets. The Classic straight pipe serves as my test jig while the inverted pipe and the folded pipe are the prototypes
so how does it sound? Depends on how you hear them. An audiophile buddy tested this and was amazed by the music of the Dai-1chi. He described the sound as similar to the lowther. But since I'm not familiar with the Lowther I take his comment as it is.
these speakers have a cut off tuned to 40 Hz. When measured, 40 Hz
has a measured SPL of 89 dB (C weighting on a Radioshack SLM) while at 20 Hz,
the SPL was measured at about 79 dB. I designed them this way to get the full
range response from a pair of speakers without the aid of a subwoofer."
hope it isn't to long. the pictures are with me.
btw, where can you get elna and capxon caps without ordering online?are they available at local stores? because as of now im using jackons, but i want to change it to better quality ones.
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moonshow,
Thanks for the insight. As for the caps, you can try at alexan and sometimes deeco also has them in their raon branch.
A short story with jackon caps. I built a gainclone using jackon supply cap and after testing it I built another using the same chip but with the respected ELNA caps. Guess what. I noticed NOTHING! There is absolutely no difference. But then again, those were my ears! ;D
JojoD
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tony,
Did you call me last nite? I was out but you can call me anytime tonight.
JojoD
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was able to build one using cheap components just for test on the kenwood reciever.
(http://groups.msn.com/_Secure/0PwDVAn4RqgkIy5TvlNsGemPWJJdyR!xuGlZ7gU0Wa61rgqqWLkhdxtBuAHJPfioqSDafBHLWl!8JAbrepNaZ1588CrQx!svn/541.JPG?dc=4675445342525158592)
The OPA541 did not work out with with my vintage kenwood.
I built another one but this time using TDA7294 since the datasheet says it can work up to 100volts.
got the schematics from this site www.email-directory.net/amplificateur/schemas.htm
Just tested the TDA7294 chips and so far, it worked without problem. :)
will post pics later
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Thanks garp for the noted TDA7294. Where can I buy this stuff for a little over P200?
I bought the TDA7294 in Raon for P190. Newport yata yung name ng store.
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rmpmla,
Congrats on your 7294. Funny thing is I believe that whoever designed the pin assignments for that chip drunk too much! Ang hirap gumawa ng pcb design nyan especially if you consider the "star ground" concept. ;D
JojoD
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JojoD,
Thanks. Actually, was not able to make PCB foil pattern for TDA7294. i used those readily available pre-drilled PCBs sa Raon. Marami nga lang jumper wires ;D.
Surprisingly, no hum was ecountered.
With CD player at pause, faint hissing sound can be heard when volume control of the Vintage Kenwood is at 12 o' clock. That is my ear is a bout 2 ~3 inches from the speaker ;D
rmpmla
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JojoD,
Thanks. Actually, was not able to make PCB foil pattern for TDA7294. i used those readily available pre-drilled PCBs sa Raon. Marami nga lang jumper wires ;D.
Surprisingly, no hum was ecountered.
With CD player at pause, faint hissing sound can be heard when volume control of the Vintage Kenwood is at 12 o' clock. That is my ear is a bout 2 ~3 inches from the speaker ;D
rmpmla
Congrats! How does it sound? I wonder why your opa541 did not work ???. As for the hissing, maybe you can eliminate that when you've set up it in a case? The lm1875 mini amp I made is dead quiet at full volume. I noticed in my case that its always grounding that's the culprit for the hum/hiss. You must know how to solder really well? ive seen the 7294 and those pins are spaced very closely.
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Congrats! How does it sound? I wonder why your opa541 did not work ???. As for the hissing, maybe you can eliminate that when you've set up it in a case? The lm1875 mini amp I made is dead quiet at full volume. I noticed in my case that its always grounding that's the culprit for the hum/hiss. You must know how to solder really well? ive seen the 7294 and those pins are spaced very closely.
Garp,
Thanks :). The sound of the TDA is not much different from AVRs that i have used, especially at low to moderate volume. For me, the hiss is already acceptable since i can only crank up to 10~11o'clock with most CD's before clipping occurs.
The OPA541 is rated for 80 volts supply and my kenwood rcvr has a 96 volts supply rails. since this is just a sample chip have tried it anyway and after a few minutes of distorted sound, umusok yung chip ;D
I still have some sample OPAs and will try to build one for my 15"klipsch subwoofer. :)
rmpmla
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Guys,
I told you, whoever designed the pin configurations for the TDA7293/4 must be drunk. And not just that, a 0.1 spacing between pins too, he/she must be near sighted too! HAHAHAHA ;D
Anyways, it gives me great joy to see that fellow pinoys can appreciate the sound of a gainclone, besides, music is a part of life for most Filipinos like me.
JojoD
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Anyways, it gives me great joy to see that fellow pinoys can appreciate the sound of a gainclone, besides, music is a part of life for most Filipinos like me.
JojoD
Oo nga eh. There's only a few of us who are really interested in gainclones. Most guys here I notice are into tubes--and understably so because I've heard tubes and they sound really nice. But I'm coming from a perspective that tube sound is not the only way to enjoy audio, however contentious that sounds to a lot of audio enthusiasts. The gainclone is such an underdog because it has to contend with biases against not only solid state but also IC's. The superlative reviews on the gaincard however is so hard to dismiss and knowing that you can clone one for an amount just a tad bit more expensive than a pair of the cheapest hammond 125ese output tranny, how can you not be curious and give gainclone diy a try?
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Garp,
You took the words out of my mouth! ;D
Gainclones are supposed to sound as if they were tubes, that is the main goal of the designers since discrete ways of reproducing tube sound is so complex but not impossible. Due to those circumstances, the only way to realistically accomplish such an ordeal is thru large scale integration, and so, welcome chipamps! Yepee!
I once opened a super cheap vcd player (those 1,299.00 pesos ones) with a speaker connector on the back. To my surprise, I found a TDA2030A powering the amp! The sad part was the design, poor layout, extremely poor power supply, and an unimaginably poor heatsink! But the darn thing works and sounds well too! But not that powerful though. Heck, what can you expect from 1.2K!
JojoD
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guys,
just finished my prototype gainclone preamp. it sounds quite good. i wish i could finish the gainclone before christmas.
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Hi homer,
Congrats on your preamp! Building a gainclone really doesn't take too much time, it is the chassis that takes much of the building time. :o
JojoD
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Oo nga eh. There's only a few of us who are really interested in gainclones. Most guys here I notice are into tubes--and understably so because I've heard tubes and they sound really nice. But I'm coming from a perspective that tube sound is not the only way to enjoy audio, however contentious that sounds to a lot of audio enthusiasts. The gainclone is such an underdog because it has to contend with biases against not only solid state but also IC's. The superlative reviews on the gaincard however is so hard to dismiss and knowing that you can clone one for an amount just a tad bit more expensive than a pair of the cheapest hammond 125ese output tranny, how can you not be curious and give gainclone diy a try?
garp, you can count me in... i'm very much interested. the only thing keeping me from getting my hands on one is the DIY ("damage it yourself" in my case... hehe ;D)... i'm the type who will rather buy one than build one... that's why as far back as the 1st few pages, i've been waiting for someone with an enterprising spirit to offer this for sale just like the wiredstate guys do. more options, more fun!!
homer, congrats! pictures naman... do you have a link to the circuit? thanks.
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akyatbundok,
Hi, if you wish, I can build a stereo gainclone for you! I am almost finished in my tower speaker project that I will pair for my SS power amp so that when someone wants to audition my amps, we have a pair of speakers to listen to!
Chassis can be something like the one I used in my ss amp found in my website. There is a smaller one just like that.
Email me at [email protected] if your interested.
I hope this post doesn't upset our beloved moderators. :)
JojoD
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JojoD, sent you email... thanks!
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Leiko,
Just finished a stereo TDA2050 gainclone and got it connected to my tower speakers. Sounds and handles very goodl for such a small chip. PCB is 1.25" X 2" per channel only! ;)
JojoD
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What are the differences of these lm3875 variants: MDC, MWC, T, TF? Which one is used in Thorsten's inverted GC?
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Am not sure of the mdc, mwc because they don't appear in the datasheet. T is for the non-isolated version so if you don't use an isolation pad between the chip and the heatsink, your heatsink will be at V-. The TF is the isolated package--no need for insulator but might require a larger heatsink. Most use the T version because of better heat dissipation. The thorsten circuit uses either LM3875 or LM1875. Recently however a lot of the gaincloners are reverting to the NI config. According to them, it sounds better than inverted.
This NI config is the actual config of the Gaincard I read:
http://www.geocities.com/rjm003.geo/rjmaudio/diy_gc.html (http://www.geocities.com/rjm003.geo/rjmaudio/diy_gc.html)
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I absolutely agree!
JojoD
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for clarification lg po: LM3886 less power than 3875? 3876 has both muting and the power of 3875?
will LM3876 make a good chip for this project?
salamat :)
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I think these are the main differences:
LM3886 -optimised for 4 ohm loads, delivers up to 68w into 4 ohms and 50w into 8 ohms
Lm3875-optimised for 8 ohm loads. Max: 45w into 4ohms, 60w into 8 ohms
Im not sure because I haven't tried LM3876. But the talk in the forum is that the chips with mute function is not as good as their non-mute counterparts. Take that with a grain of salt though. LM3886 has mute and yet it's what Jeff Rowland used in one of their amps. LM3875 however is the majority choice.
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LM3886 -optimised for 4 ohm loads, delivers up to 68w into 4 ohms and 50w into 8 ohms
Lm3875-optimised for 8 ohm loads. Max: 45w into 4ohms, 60w into 8 ohms
this is exactly what confuses me when i read the datasheets. ??? i thought that 'rating' in terms of Z will always be the same across amps. in other words, all amps behave exactly alike given similar Z/loads. have read somewhere that amps with lower Z (like 4) are actually more durable or reliable. does that apply here? salamat once again.
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have read somewhere that amps with lower Z (like 4) are actually more durable or reliable. does that apply here?
Not necessarlly, you see, gainclones are optimized for a particular load but that doesn't mean you can't use a lower or higher Z in the output. Load impedances are influenced by so many factors, circuit topology, rail voltage, etc...
JojoD
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Leiko,
I have successfully :D updated my website. It now has some pics of the TDA2050 I recently put up. It also has some pics of my MTM speaker project.
http://www.geocities.com/jojod818/index.html
best regards,
JojoD
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Hi guys,
I tried an opamp buffer in my gainclone and immediately noticed a big difference in the sound. It made the sound more whole and the highs are not edgie. However, I cannot compare it to what I recently tried, a tube preamp! Maybe someday ;)
JojoD
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sir JojoD, pagawa niyan ha... ;D punta ko senyu minsan.
tingin ko babagay yan sa tube preamp ko... ;)
problema na lang natin matching chassis... ::)
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Hi guys,
I tried an opamp buffer in my gainclone and immediately noticed a big difference in the sound. It made the sound more whole and the highs are not edgie. However, I cannot compare it to what I recently tried, a tube preamp! Maybe someday ;)
JojoD
I've tried the tube buffer but for some reason I can't tame the highs but then I still need to break it in. I'm now doing an opa541 NI using gaincard specs. If this works out ok I plan to mate it with the WS preamp. Jojo, for the zobel network I need a 1R resistor, what should be the power rating for that? What would be better--metal film, carbon, or metax oxide? thanks.
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Garp,
I would use a 1R 2-5W rating. The choice of make is up to you. Though I have tried using 2W 5% tolerance carbon composition resistors with great success.
akyatbundok,
no problem kung magpapagawa ka, pasyal ka dito sa amin minsan. Si Leiko nadinig na ito gc amp ko.
My mini gainclone (TDA2050) keeps getting better and better.... I always keep it powered up though.
JojoD
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Hi Jojo,
You've worked on the OPA541 right? What was the gain? I've tried 3 so far: 33, 22, and 10. There's quite a bit of distortion at 22, a lot at 33, and dead quite at 10. I like the sound of the OPA541 using a gain of 10. What's your experience here? Thanks. I can settle for 10 because I've paired it with the WS preamp.
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Garp,
My OPA541 runs at a gain of about 22. I have also tried lowering it to 10 but went back to 22 for a more "standard" gainclone concept.
I am so busy with a new gainclone concept that uses current dumping for handling lower loads. I sure hope it works as it did on paper! ;D
BTW, Happy Holidays!
Regards,
JojoD
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Thanks. Do let us know of your new concept. I'm interested to know.
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Hi guys,
I was doing the laundry ;D when something pop in my head about gainclones! Well, I think I'll have to try it first. :P
Happy Holidays,
Jojo
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Here's my simple OPA541 gc circuit. No input cap but with zobel at the outs. Configured for a gain of 10x (R2 and R1, 22K and 2.2K resp.) . Sounds very very nice.
(http://www.imagestation.com/picture/sraid95/pdbd095bc2bcaa055c020c428157aa492/fa278d2b.jpg)
WS preamp (highly recommended) driving the opa541 monoblocks. The one below is the power supply, one 160va toroid per channel.
(http://www.imagestation.com/picture/sraid95/p46e7dc6822460bfea0f617ad207ae7d1/fa278c33.jpg)
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garp,
congrats on your gainclone. where did u get the power supply chassis?
-
Garp!
Nice looking implementation! Very neat indeed :D.
I also just finished another set of OPA541 with a 24-0-24 trafo. Sounds very big indeed. BTW, what is the voltage rating of your trafo?
Happy break-in!
JojoD
Homer,
You can buy those casings somewhere in raon.
Regards...
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jojo,
tnx. meron b sa deeco? sa solid electronics?
-
thanks jojo, homer. Am still a bit awe struck.
Homer,
The casing is from Deeco, about 500 plus. I think that's already expensive because I've seen some at Raon of the same size and gauge but a bit taller that sells for not more than P300. Forgot the name of the store but its about 3 or 4 stores away from SMR electronics, kahanay niya. Also try eleshop.
Jojo,
My trafo is 18-0-18 or 50v dc . A bit low since the OPA can take 80v. Did you use a current limit resistor on the 541 BTW? Thanks.
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Homer,
You read my mind... both shops have those.
Garp,
I did use a 0.1R as currentr sensing. I did try to short it out but the sound didn't changed so I just left it in.
Your rail voltages are kinda low but not that alarming ;D. I used a 24-0-24 and the chip is happy indeed. I am listening to the amp as I type this, it sounds "brusko" to me.
More break-in for me though ;D,
JojoD
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Brusko? Wow, I was going to say mine was very smooth. And its not just because I have tube preamp but I tried just an ordinary pot using same config and its still kind of mellow compared with the Inv LM3875. Although mellow, the detail is still very nice. Maybe it has to do with the my low secondaries? I have a 24-0-24 in the same power supply, will do a mono test.
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Garp,
I think the tube preamp has nothing to do with it, as you said, you can try using your gainclone without the tube preamp at the moment just for testing. Your 24X2 trafo would be much better than your 18X2, I have tried them both. More punch with a 24X2. ;D
JojoD
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Here's my simple OPA541 gc circuit. No input cap but with zobel at the outs. Configured for a gain of 10x (R2 and R1, 22K and 2.2K resp.) . Sounds very very nice.
(http://www.imagestation.com/picture/sraid95/pdbd095bc2bcaa055c020c428157aa492/fa278d2b.jpg)
WS preamp (highly recommended) driving the opa541 monoblocks. The one below is the power supply, one 160va toroid per channel.
(http://www.imagestation.com/picture/sraid95/p46e7dc6822460bfea0f617ad207ae7d1/fa278c33.jpg)
congrats garp! any chance i can get to audition these amps. if possible, okay for me to try them at home so i can test them with various speakers and sources?
thanks in advance. where are you staying?...am at the south.
mabuhay ang DIYers! mabuhay and Pinoy!
v 8)d
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congrats garp! any chance i can get to audition these amps. if possible, okay for me to try them at home so i can test them with various speakers and sources?
thanks in advance. where are you staying?...am at the south.
mabuhay ang DIYers! mabuhay and Pinoy!
v 8)d
Hi VD!
Thanks. It would be great to get a different perspective on the gainclone and I'm all for it--be it good or bad. But I'm not sure about the logistics though because I'm in Cavite City. I actually want to attend one of your tube listening sessions but time and distance do not permit me.
I will advance my congratulations to the wiredstate team on the 300B amp that's in the works. Judging by what others have said in the thread after listening to the prototype, looks like it will be another blockbuster like your TB 2a3 and the WS preamp. I have eagerly followed the team's progress since TB 2a3 and look forward to hearing more about your other projects.
-
A glowing review of AMP-2, Peter Daniel's non-inverted gainclone. This amp's development is well documented at diyaudio.com including schematics, part values, and brand. The parts used are not cheap--Vishay SJ102 input resistor (P1k at farnell), Caddock MK132 (?)for feedback, Riken from inverting input to ground, Blackgate for filtering and Plitron 400VA trannies. But unlike AMP-1, PD doesn't use blackgate DC blocking caps here.
http://www.6moons.com/audioreviews/audiozone/amp2.html (http://www.6moons.com/audioreviews/audiozone/amp2.html)
(http://www.6moons.com/audioreviews/audiozone/two.jpg)
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just finished another TDA7294. wires are still longer as i still thinking of how i will make my chassis :)
(http://groups.msn.com/_Secure/0QwDqAuESpmb8K9QkoeCoiaM*XUfHbKGoxEhHCZuitio2LXSrD2EE*NoipyyD5IqPwpy4bpGKwg!O2kay1Cp*g!NMWU8cA2w7qb8wz68tyQg/tda7294.JPG?dc=4675453967838446090)
sound is okay. although there is a slight distortion/noise (with CD player on pause) that is if you put your ear about one inch from the speaker.
with my test speaker bose 401
(http://groups.msn.com/_Secure/0RADqAkITlH*8K9QkoeCoiQvIbV8zrQAAp2xnB8UA4vldwPfLZGF051iA!PcHAV4R28jNCfgM9tDzWGu94!3G04Mq5mjRPTB83T*qHGKO!jU/tda7294a.JPG?dc=4675453967964586098)
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this one is a bridged opa541.
tested a pair of brided opa541. noticed that one channel is slightly distorted while the other one is dead quite even at full volume ( cd player at pause ).
found out that i installed a wrong input resistor on one of the opa541. but too late na yata kasi ayaw na tumunog nung distorted na channel. while the other one still works fine.
i would prefer the sound of the brided opa compared to the TDA.
here is the pic of the bridge opa with a line driver drv134
(http://groups.msn.com/_Secure/0TAAXAwQWLEjttIg6rIHkQ1VvPZObQvmWXExumUEY3xeXQwRMDGpZvL168WqABRJyrz4A5tyYNTOVUztyhZm1lC9bMxEN6RAfHgfOXPfAbFgt7MHcVC01dw/bridged%20opa541.JPG?dc=4675453968046535664)
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hi rmpmla,
congrats on your chip amps. how did you make the pcb's?
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hi rmpmla,
congrats on your chip amps. how did you make the pcb's?
homer,
Thanks. I just bought those pre-etched/pre-drilled boards in raon which cost for P35.00 and each board can make up to three gainclones.
will post a close up of another GC board this time an OPA549 :)
-
Look forward to seeing the finished product. Good luck!
-
garp,
Thanks. Actualy, i have some ideas already after seeing those GC from the net, especially Peter Daniel's work :). but due to materials constraint, i might stick to wood and aluminum/metal sheet.
Hope it turns out okay :)
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hi rmpmla,
congrats on your chip amps. how did you make the pcb's?
these are the OPA549s installed on pcb
(http://groups.msn.com/_Secure/0QgDSArQS*VmG5wwOzWLpoHw8bzoSy2CXLB59caoZOWpQ3JKzxLpQNrqLDRb2SOR4FvnEb6W51RLYdmgo6YcY9B8j4mUB1SacUr789zpPQoI/opa549.JPG?dc=4675454066749602228)
close up
(http://groups.msn.com/_Secure/0UAAAAO0WHI!G5wwOzWLpoEVvzdA33QtVN63XSV0iCBUaIFNXuxYQCLtp!HwoQaS1VRr1LcO0om9!kM1y!n9byz26ejQpTLRtjzWrComBMKkk7nhyeR0AkwAAAAAAAAAA/opa549%20close%20up0.JPG?dc=4675454066923612032)
not nice looking but works out fine for my TDA and opa541 :)
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Congrats to all of you guys for your successful gainclones! May you have more sounds and less smoking parts! ;D
JojoD
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this one is a bridged opa541.
tested a pair of brided opa541. noticed that one channel is slightly distorted while the other one is dead quite even at full volume ( cd player at pause ).
found out that i installed a wrong input resistor on one of the opa541. but too late na yata kasi ayaw na tumunog nung distorted na channel. while the other one still works fine.
i would prefer the sound of the brided opa compared to the TDA.
here is the pic of the bridge opa with a line driver drv134
(http://groups.msn.com/_Secure/0TAAXAwQWLEjttIg6rIHkQ1VvPZObQvmWXExumUEY3xeXQwRMDGpZvL168WqABRJyrz4A5tyYNTOVUztyhZm1lC9bMxEN6RAfHgfOXPfAbFgt7MHcVC01dw/bridged%20opa541.JPG?dc=4675453968046535664)
just build another bridge opa541 using TO-3package to replace the broken one. this one has no pcb but a point to point connection was done.
both cahnnels now working. however, i noticed that when i changed the gain from 10 to 22 (by replacing the resistor ) distortion was introduced. will revert back to gain 10 and see what happens :)
(http://groups.msn.com/_Secure/0WAAAAJMZtG8yvU0vhYq*vcnTLykF01*oeMUHnBhPCfHwCjbOkKEJoIRQyQVgoI0ARFfCnruY01KO*qig4Cj4uZVez3b9dkqg1bpgZa1SBsWZXjsq!mWhaoix2bPkAFpCAAAAAAAAAAA/pair%20of%20bridged%20opa541.JPG?dc=4675454115613408567)
(http://groups.msn.com/_Secure/0RwAOA7kUT!FWiP5rk7nGn8s!a72g*YZucaNV1OSZF8Lxq7MhZmJAzC2gxRSGMd0ziJ7SSNc*Vu7Pn2euZqL9VBkfSi9q*2YbxS*rOwOsPwg/side%20view.JPG?dc=4675454115687356769)
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just build another bridge opa541 using TO-3package to replace the broken one. this one has no pcb but a point to point connection was done.
both cahnnels now working. however, i noticed that when i changed the gain from 10 to 22 (by replacing the resistor ) distortion was introduced. will revert back to gain 10 and see what happens :)
Same here. I tried gains of 33x, 22x on the OPA541 but couldn't get rid of the distortion. The zobel network helped but it didn't altogether disappear. Tried 10x and this time it quieted so I'm sticking with 10 at least for now.
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Congrats to all of you guys for your successful gainclones! May you have more sounds and less smoking parts! ;D
JojoD
Ha ha I think I've smoked more parts that produced successful gainclones. Hopefully the situation will be reversed soon. ;D
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Same here. I tried gains of 33x, 22x on the OPA541 but couldn't get rid of the distortion. The zobel network helped but it didn't altogether disappear. Tried 10x and this time it quieted so I'm sticking with 10 at least for now.
You are right :) the first opa541 i had has a 10X gain and it was really quite. but i was tempted to change it since the schematics i copied had a gain of 22 . Hindi ko muna ito babaguhin.
Tomorrow, i will try to wire the OPA549 and see the results. This one has a 10X gain.
-
Guys,
I test them OPA power chips using 680R/22K resistors for a gain of 32-33x with no distortion whatsoever. Must be something missing? I onced used 560R/22K combo. ;D No problem.
JojoD
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Guys,
I test them OPA power chips using 680R/22K resistors for a gain of 32-33x with no distortion whatsoever. Must be something missing? I onced used 560R/22K combo. ;D No problem.
JojoD
That's what I thought initially, 33x should be fine. Fedde of diyaudio who started the NIGC thread there used opa541 with fb of 680r/22K as well. He didn't report any problems and in fact raved about it which is how all the current fuss now about NI config started. But Mad_k also posted saying that OPA541 has limited open loop gain (whatever that means I dunno) so the usual gc schematic of 33 can't be used. According to him, OPA541 gain can be as high as 22. He chose 10x though using fb of 10K/100K. Will give the 33x a try again and see.
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according to the opa541's datasheet, the open loop gain at 20khz is less than 40db. if your closed loop gain is 33x (30db), you only have less than 10db of gain (feedback) available at 20khz.
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I agree...
However, what I meant is that I have tried those chips with feedback from 10X, 22X, 33X successfully without problems. ;)
Cheers,
JojoD
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JojoD818,
Slightly OT but I just wanted to know how thoes dai-ichi speakers you made, sound?
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getafix,
They sound great! Comparable to those commercially available floorstandings but of course it's cheaper.
Cheers,
JojoD
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gumawa ka rin ng sarili mong inductors? anong slope ng crossover mo?
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Yep, I made my own passive crossovers too...
May bago ako baby, active bandpass sub, nasa webpage ko...
http://www.geocities.com/jojod818/4th_order_bandpass/4th_order_bandpass.htm
Cheers,
JojoD
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Jojo,
anong power supply ang gamit mo duon sa opa549 na amp mo? do you have schematics of the power supply in your site? 'di ko makita.
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getafix,
Sorry, no schematics of psu in my website. I intentionally left them out to leave the decision to the constructor and his imagination. Especially if you have some components lying around there somewhere.
JojoD
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unfinished enclosure for a stereo opa 549. this one has a gain of 22 and at last, dead quiet from min to max volume ( with source at pause ).
(http://groups.msn.com/_Secure/0PwDeAhgShC!aHS3cAuN1otJSKujDw5CHxAiewwWj2ZUj5RceV1LeB3vja5hmIvovE5QtwTmAIqkqgemwR!oLjTFVDewpQiNR/opa.JPG?dc=4675457035812162844)
at the bottom of the opa GC is a Sansui eq used as a pre-amp/tone control
backview.
(http://groups.msn.com/_Secure/0QwDuAqkTSpUMmsLzM1G54umYIc7zFw6dzXmfoPABrq4LmgTsIc2gwkr4!VKW4eAkftrPN9!IcnIbKBMF05NPCW9gSR0CYHjZIuPtLYlFZ54/opaback.JPG?dc=4675457036110133359)
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my next GC that need enclosures
(http://groups.msn.com/_Secure/0SgDbAuMVIDXttIg6rIHkQ80bwpvRQWln9Qa4NcK8uoZoUhtPJf9VYTpBiCPCijDEytUvHj9mM0EmJCXOSc3PNp2mpin3dQKNysxi013baRvfQBdStEEAcQ/bridged%20opas.JPG?dc=4675457037952615472)
bridged OPA541 w/ wires and heatsinks
(http://groups.msn.com/_Secure/0SQDbAoMVMRzttIg6rIHkQ2YJmULfjEadNHAVeJdhVwfd28Apjye0IBuddITVeJIgAdoKvrvT*rCINFiyYQ6pQHn8QJfypeU2fuEmPRyka*MO9hHPCXCL1g/bridgedopa541.JPG?dc=4675457038048833874)
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Hey looks good. What circuit are you following? That wooden box looks nice, but are you planning to shield it with foil?
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thanks garp. here is the site where i got the circuit
http://www.freewebs.com/matttcatttweb/audio.htm
foil shielding would be great :). probably apply this on my next enclosure.
Was not able to complete finishing on GC w/ wooden enclosure. Inuwi na kasi nung Karpintero ko. Excited eh ;) , siya na raw ang magtatapos nung enclosure.
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Finally, my TDA 7294 GainClone :)
(http://groups.msn.com/_Secure/0RAAAAL4SPF4iQgIeKlaIzHlkqC0EYEFIfjGd08XjUn7PBbScnaOmU*5g8Rv7dSb1!Xah93aPSRF0TYP7FIZjNwX*tHIZJA*TtATyWzEAqvI/TDA%20GC.JPG?dc=4675458534596374047)
Here is the Finished TDA GC. Magaspang pa ang pagkagawa ng enclosure. konting practice pa ;D
(http://groups.msn.com/_Secure/0UADYAqAWZoHqL!HZE4xdUybe4TdA1QjRLz8XbSsA7sXKQr5DB95ZRg2va*VoFjOVHs2N5AQsvc5iTM!e0KaHcpT4bzYi4qLfd!FYjlPZlrD1r6cChgOciHSCEBgAcBAY/Finished%20TDA%20GC1.JPG?dc=4675458535093508558)
This one easily drives my Bose 401.
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Finally, my TDA 7294 GainClone :)
(http://groups.msn.com/_Secure/0RAAAAL4SPF4iQgIeKlaIzHlkqC0EYEFIfjGd08XjUn7PBbScnaOmU*5g8Rv7dSb1!Xah93aPSRF0TYP7FIZjNwX*tHIZJA*TtATyWzEAqvI/TDA%20GC.JPG?dc=4675458534596374047)
Here is the Finished TDA GC. Magaspang pa ang pagkagawa ng enclosure. konting practice pa ;D
(http://groups.msn.com/_Secure/0UADYAqAWZoHqL!HZE4xdUybe4TdA1QjRLz8XbSsA7sXKQr5DB95ZRg2va*VoFjOVHs2N5AQsvc5iTM!e0KaHcpT4bzYi4qLfd!FYjlPZlrD1r6cChgOciHSCEBgAcBAY/Finished%20TDA%20GC1.JPG?dc=4675458535093508558)
This one easily drives my Bose 401.
Congrats! You are truly a master craftsman!
Cheers,
JojoD
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Nice work! Did you use MDF for the enclosure?
Sir Jojo, kumusta na? Anong pinagkakaabalahan mo ngayon? :)
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Jojo, Garp,
Thanks. Actually, i was not the one who made the enclosure :). I tried doing it by myself using MDF boards and it looks ugly. End up in the trash ;D. Timely naman, I hired a finishing carpenter to do my cabinets and shelves at home. I asked him to make some extras , a pair of stands for my bose 901, and 4 enclosures (made of MDF boards) for the gainclones.
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Nice work! Did you use MDF for the enclosure?
Sir Jojo, kumusta na? Anong pinagkakaabalahan mo ngayon? :)
Tubes.... Also finished my ported subwoofer project. Ikaw musta na mga projects mo?
JojoD
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Mga Sir's
Query lang po.
What is the Power Output of a OPA541 and OPA549 OP Amp.
Thanks
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FASTBACK,
The data sheets for OPA indicates output current.
But i found this Burr Brown application bulletin which might help :)
(http://groups.msn.com/_Secure/0RgAAAOETjqgaqanCZ92rPeTcMdMg84ocm9uAYRjZEbRCieFWxtlRtFonhJxdQ0BiAB6883EIp9Ug3tPNAJlYKY4NQooPGRfuzzKn5n0Vcyo/OPAAPPS_4a.JPG?dc=4675459078433409628)
i can e-mail you the PDF format Burr Brown application bulletin.
-
Right now, i'm working on another OPA541/549 this time using aluminum enclosure.
Was looking for ready made metal cases in Raon and find it too ordinary( and not so cheap ;D)
So i end up with this
(http://groups.msn.com/_Secure/0UQDUAn4XW767XmrImK6Kwnrf67KTRuBIxA12uVzjfyGb7MGpwVGHCo*flakTSJsb68na6J96E1FSkgaVWvTLHbsOVeiVNBSWId!ImCeUfBzsNvpDFAAGRxBFAVo9EwRI/opened%20alu%20opa541.JPG?dc=4675459078259940671)
Transformer mounted on the heat sink.
(http://groups.msn.com/_Secure/0SADUAnwU0tUxCnNwCcvKnEqs1eI8DikL411LszHf0bHMi7EuEMMfCSwEmem36SOZzhfVClj8ZsMTmqQiNjHd7dYnmJyAotnyok6pn3ovLiczAAAArXJdAg/alu%20opa541.JPG?dc=4675459077835486551)
All heat sinks on four sides. Maybe i will use thick aluminum sheet or acrylic sheet for the front and back plate.
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rmpmla,
I have tried one of those and I believe your chassis design using heatsinks for four sides will most benefit if it were used with a 5.25" muffin fan ala wind tunnel. Such an enclosure will be useless without forced air cooling. But that's me :D.
JojoD
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rmpmla
Thanks for the information.
Ok sir please send me the Burr Brown application Bulletin.
I'll Send you a PM.
Thanks
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rmpmla,
I have tried one of those and I believe your chassis design using heatsinks for four sides will most benefit if it were used with a 5.25" muffin fan ala wind tunnel. Such an enclosure will be useless without forced air cooling. But that's me :D.
JojoD
Thanks for the suggestion :).
I will try this first w/o fan.
I was thinking of putting one but problem is where to install it. I plan to put the jacks and switch at the back cover and the pot at the front cover. May be i can still fit CPU fan at the back cover.
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rmpmla
Thanks for the information.
Ok sir please send me the Burr Brown application Bulletin.
I'll Send you a PM.
Thanks
FASTBACK,
Sent you an e-mail :)
rmpmla
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rmpmla
Ok sir got your e-mail.
Thanks
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FASTBACK,
Do you still have your LM12s with you? Why not build a pair so that you can compare?
JojoD
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JojoD818
I still have the LM12 I am still in the process of buying the parts needed. I got hold of the OPA549 and OPA 541 samples kasi from TI kaya I got interested then in making this amp.
Sana ma complete ko na yung mga parts para assembly stage na. keep you posted.
Thanks
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JojoD818
I still have the LM12 I am still in the process of buying the parts needed. I got hold of the OPA549 and OPA 541 samples kasi from TI kaya I got interested then in making this amp.
Sana ma complete ko na yung mga parts para assembly stage na. keep you posted.
Thanks
Best of luck! Good parts hunting to you!
-
OT: ey jojo, congrats on your tube preamp 8)
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OT: ey jojo, congrats on your tube preamp 8)
Thanks arnoldc. Wish me luck on my next tube preamp projects. ;)
Some guys have already emailed me asking for auditions, though I think it's too early. So many room for improvements.
Cheers,
JojoD
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tube preamp?! Congrats JojoD818! Details naman. ;D Will you post it in your website? My first question is where did you get your xformers?
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tube preamp?! Congrats JojoD818! Details naman. ;D Will you post it in your website? My first question is where did you get your xformers?
Thanks Garp, will post it soon in my website once I finished tweaking and improving it. It was conceived due to several orders in the past that I turned down since I was so busy with solid state stuff. The goal was to build a tube preamp that is cost effective but must pass the less merciful hunger of Filipinos for high quality audio equiptment. BTW, I call it Prerotica ;D
Power transformer was made by a close friend while the choke that I used was made by none other than me.
I am so sorry for posting so much OT on this thread. ;D
JojoD
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PREROTICA thread please ;D
-
PREROTICA thread please ;D
your request has been granted!
-
Right now, i'm working on another OPA541/549 this time using aluminum enclosure.
Was looking for ready made metal cases in Raon and find it too ordinary( and not so cheap ;D)
So i end up with this
(http://groups.msn.com/_Secure/0UQDUAn4XW767XmrImK6Kwnrf67KTRuBIxA12uVzjfyGb7MGpwVGHCo*flakTSJsb68na6J96E1FSkgaVWvTLHbsOVeiVNBSWId!ImCeUfBzsNvpDFAAGRxBFAVo9EwRI/opened%20alu%20opa541.JPG?dc=4675459078259940671)
Transformer mounted on the heat sink.
(http://groups.msn.com/_Secure/0SADUAnwU0tUxCnNwCcvKnEqs1eI8DikL411LszHf0bHMi7EuEMMfCSwEmem36SOZzhfVClj8ZsMTmqQiNjHd7dYnmJyAotnyok6pn3ovLiczAAAArXJdAg/alu%20opa541.JPG?dc=4675459077835486551)
All heat sinks on four sides. Maybe i will use thick aluminum sheet or acrylic sheet for the front and back plate.
made some changes to lower down cost
(http://groups.msn.com/_Secure/0QwAJAwcTSXAT8R!Z*Zr*YyxLFWjIYM40kEMeL2e5dNzSOYmhtjA0uNo7bEeCfL9ToXLCyM5!Pq2*PJ99frpMgFbLZeh3SEW5BVcwC7TZzkQ/opa541a.JPG?dc=4675460455340156279)
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This one has switchable input for two connected sources. My officemate requested such so he can connect his CD and tuner.
(http://groups.msn.com/_Secure/0QwAAAAgThHAT8R!Z*Zr*Yz9PWav6v3*O7uEBrXhEO08t*QDd2bPmbt06YCRGwWDjLoynl4gT6XEFEbETT2PBPBfICd9kCZELCixmjyMXUCA/opa541b.JPG?dc=4675460455449343892)
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Finished OPA541 GC
(http://groups.msn.com/_Secure/0SwAAAMMVnS8T8R!Z*Zr*Y4LnyCghzEhtSltBgEoCkPFwKt8VoCP5BEBzcgJWYd!86UDNXIF8SOgi1qC58oaJqbMTE1FvBsoC3zv19v*MQ*cwT7qTLQPplg/opa541w%20cover.JPG?dc=4675460455590802616)
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Aha! Excellent work!
-
Wow galing. How does it sound? Just to share my experience. Initially I was disappointed with my OPA541 GC. Although I thought it sounded good, it just wasn't involving.
But after using it for 2 months, the change in sound is just so dramatic that everytime I listen to it now I have to wonder if my ears are deceiving me. I did a lot of tweaks (using bypass caps in the PS, change wires, added a DC blocking cap, used a single bridge for one trafo instead of the usual 2), but really the best sound I got was from using the most simple setup---no bypass caps, no dc blocking cap, but 2 diode bridges.
I will second Jojo on that---let's hear them GC's.
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Garp, All GC Guys,
A lot of debate has come and gone on the issue of break-in of electronic circuits. IME, I never judge a new-born amp, whether it is a GC or an SS amp. I always give it some time to break-in, especially the caps in the circuit. I even leave them on 24Hrs.
So as a tip, before you attempt to tweak a project, please let it sit around as is for a while until it has broke-in so when you tweak, you notice a difference before and after the tweak.
But hey! That's just me... :P
JojoD.
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Here is a 549T that took 48 hours to break-in.
(http://img23.photobucket.com/albums/v70/jojod818/OPA549T_Buffered/OPA549T_Buffered0000.jpg)
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To preserve the feedback loop of this GC with varying positions of the input pot, I included an input buffer to isolate the input from the pot. ;D
(http://img23.photobucket.com/albums/v70/jojod818/OPA549T_Buffered/OPA549T_Buffered0002.jpg)
And a close up...
(http://img23.photobucket.com/albums/v70/jojod818/OPA549T_Buffered/OPA549T_Buffered0001.jpg)
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Garp, All GC Guys,
A lot of debate has come and gone on the issue of break-in of electronic circuits. IME, I never judge a new-born amp, whether it is a GC or an SS amp. I always give it some time to break-in, especially the caps in the circuit. I even leave them on 24Hrs.
So as a tip, before you attempt to tweak a project, please let it sit around as is for a while until it has broke-in so when you tweak, you notice a difference before and after the tweak.
But hey! That's just me... :P
JojoD.
I agree with you there. I let the amp sit in for a while although now that you've mentioned 48 hours, I'm thinking maybe I don't wait long enough for it to break in. Hmmm...
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Jojo, Garp,
Thanks :)
Jojo, your completed projects are still the best :).
Garp, at low volume, both OPA 541 and OPA549 produces clean/detailed sound. ang TDA7294 ay magaspang.
At high listening levels, OPA541 distorts easily, then followed by OPA549, and last is the TDA7294.
with the three GC's i built, i would prefer the sound of OPA549 :)
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rmpmla,
I agree with your observations on the three GCs you mentioned.
Garp,
48 hours break-in is subjective, it can only be an hour or even a month! I think yours took 2 months?
JojoD
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Here's a weird thing I did almost a year ago before I've been able to post here at PinoyD.
OPA541 - Mid/High (Non-Inverting)
OPA549 - Low (Non-Inverting)
TDA7293 - Sub (Paralleled w/ Phase Adjust)
Results were extremely excellent!
I built an active crossover for that project but I can't seem to find it anymore? ??? If I do, I'll share it with you guys or you can even build your own design for that matter.
You see, the gainclone projects never seems to stop doesn't it? ;D
JojoD
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You see, the gainclone projects never seems to stop doesn't it? ;D
JojoD
Tama ka dyan ;D.
An officemate wants a repeat and another requested for the same thing ( aluminum case ).
But before that i will build GC amps for my own use :). One will be an OPA 549 bridge+parallel stereo AMP and next would be a multi-channel OPA549 for direct connection to the 5 analog outs of my SAST DVD player.
Will post end product as soon as it is finished.
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But before that i will build GC amps for my own use :). One will be an OPA 549 bridge+parallel stereo AMP and next would be a multi-channel OPA549 for direct connection to the 5 analog outs of my SAST DVD player.
Will post end product as soon as it is finished.
Same here, I plan to buy a Kebao DVD player and build myself a multichannel gc for HT.
Hope to do that project soon. ;D
JojoD
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Seeing the pictures and reading your post makes me think that I have been left behind already in term of building my own GC.
I am still on the process of sourcing the parts I need for my project.
I plan to build a bridge parallel configuration on my LM12.
any suggestions will be greatly appreciated.
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I plan to build a bridge parallel configuration on my LM12.
any suggestions will be greatly appreciated.
FASTBACK,
i'm not familiar with the LM12 but if you have some OPA samples you may try this http://www.freewebs.com/matttcatttweb/audio.htm
This i plan to use for my bridge+parallel GC.
Good luck :)
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rmpmla
Thanks for the link.
Got my OPA samples already and would love to try building a GC using this IC.
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rmpmla
Thanks for the link.
Got my OPA samples already and would love to try building a GC using this IC.
A TO-3 Package LM12 in a bridge-parallel config will surely be a powerful amp. You can use the same approach as to the recommended topology by National Semiconductor in one of their technotes. Try searching for "bpa200" in your favorite search engine.
Good luck,
JojoD
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JojoD818
Thanks for the input. I already downloaded the Bpa200 file.
I based the design of the amp to that bridge-parallel cofiguration indicated on the technical notes.
How I wish I could someday post my project here just like you guys.
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FASTBACK,
i'm not familiar with the LM12 but if you have some OPA samples you may try this http://www.freewebs.com/matttcatttweb/audio.htm
This i plan to use for my bridge+parallel GC.
Good luck :)
rmpmla
Sir in the circuit indicated on the webpage specifically the bridge and Bridge-parallel, What IC will you use in the input stage? I'm not familiar with the schematic symbol.
Thanks
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rmpmla
Sir in the circuit indicated on the webpage specifically the bridge and Bridge-parallel, What IC will you use in the input stage? I'm not familiar with the schematic symbol.
Thanks
FASTBACK,
Sorry about that :). It is a DRV134 also from texas instruments. So, you can also get samples of it.
Have tried the bridge configuration before and it works
;D
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rmpmla
No problem sir Thanks.
I'm begining to buy the parts that I'm going to use in my gainclone. though I'm still missing the power transformer and heatsinks.
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FASTBACK,
If this would be your first try to build a gc, may I suggets that you start with a simple single ended amp. May it be an inverting or non-inverting topology does not matter. Building a straight bridge parallel gc may be a bit complicated if it's your first time.
Just my 0.00001 cent or whatever. ;D
JojoD
PS. Currently building a P3A ss power amp with semi-exotic parts to compare with gc. Exciting!
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JojoD818
Thanks for the advise. I have that in mind. I'll build a single ended amp on an experiment PCB first for testing purpose and off to do a Bridge parallel configuration both on the LM12 and the OPA549. I bought tons of resistors and capacitors for this purpose the other day.
I also started looking for my other assembled projects like the LM1040 tone controls incorporate it in the gainclone amp.
GC guys
Do you have an Idea what IC was used for the Alexan car amplifier? I can't remember, I buit this as a school project when I was in 2nd year college, When I sold the car I didn't bother to remove the amp.
Thanks
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FASTBACK,
Alexan used the LM2005T automotive chipamp from national semi. What a coincidence? I also have a 1040 and 1035 tone preamps. What I love from those preamps are the fact that they use dc for the controls.
Cheers! ;D
JojoD
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Hey sorry slightly OT but do you know if these are available locally: 2SK1058 (N-Channel) and 2SJ162 (P-Channel MOSFETS? I'm intrigued by Rod Elliots new project (P101) which he claims is "reference" quality in all respects. According to him, with the full supply voltage of +/-70V, RMS power is around 180W into 8 ohms, or 250W into 4ohms.
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Garp,
Will try to go to some shops tomorrow and will ask. However, the main reason I steer away from mosfets is that they are soooo expensive compared to bjt. Anyway, a project is a project. :P
JojoD
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Garp,
Will try to go to some shops tomorrow and will ask. However, the main reason I steer away from mosfets is that they are soooo expensive compared to bjt. Anyway, a project is a project. :P
JojoD
Hi Jojo. Thanks for the reply. I saw the prices of those MOSFET online and they're so expensive pala. Sige right now I'll just enjoy my GC--switched chips nga pala to OPA549 from OPA541. I like its sound better than OPA541--more weight at the lows pero smooth pa rin. I think however the slight edginess will disappear after some time because this was my experience with OPA541.
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Hi Jojo. Thanks for the reply. I saw the prices of those MOSFET online and they're so expensive pala. Sige right now I'll just enjoy my GC--switched chips nga pala to OPA549 from OPA541. I like its sound better than OPA541--more weight at the lows pero smooth pa rin. I think however the slight edginess will disappear after some time because this was my experience with OPA541.
I told you they were expensive. ;D
On your GC, just let it on for about a day (even without playing) and your sound will open up. I don't know how this can happen but it happens, don't ask me to explain it. ;) Magic maybe? :o
JojoD
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FASTBACK,
Please email tony at [email protected] and ask for a copy an article about LM12 gcs. I believe it already has pcb designs and stuff that can help you.
Regards,
JojoD
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JojoD818
Thanks for the info. regarding the car amp project I only remember the price of the chip before which is 50 pesos.
Hey guys built myself a GC amp based on a OPA548 chip
Like the author of the web site garp recommended commented, he was impressed on how a simple circuit performs. Right now I'm listening to it connected to my PC
I built a 4 ch and plan to build another ch and a bridge configuration for my PC setup.
Thanks
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JojoD818
Thanks for the info. regarding the car amp project I only remember the price of the chip before which is 50 pesos.
Hey guys built myself a GC amp based on a OPA548 chip
Like the author of the web site garp recommended commented, he was impressed on how a simple circuit performs. Right now I'm listening to it connected to my PC
I built a 4 ch and plan to build another ch and a bridge configuration for my PC setup.
Thanks
Congrats on your successful gc!
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Hey guys built myself a GC amp based on a OPA548 chip
Like the author of the web site garp recommended commented, he was impressed on how a simple circuit performs. Right now I'm listening to it connected to my PC
I built a 4 ch and plan to build another ch and a bridge configuration for my PC setup.
Thanks
FASTBACK, congrats :)
good luck on your next GC projects.
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JojoD818 , rmpmla and all GC builders.
Thanks for sharing your know how regarding GC.
By the way I built an Inverting GC amp, I would also like to do a non inverting to compare the if there are any difference in the sound quality.
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Here is a close-up my OPA548 GC amp.
(http://groups.msn.com/_Secure/0TwDKAokWQWjy1kapSbQPium4zykN39*uwHXaW!a8w!1NKmKrVfT6EbRJMzVFDzwstGDWrXROySKlFjAhN8iNpY*8xieszrzi4cVaqafuyOG5eYIQ4CyDGA/OPA548%20Quad%20amp.jpg?dc=4675462418961546691)
Used an improvised heatsink for testing purpose only. I haven't bought a larger heatsink yet. I'm still thinking on what chassis to use.
Sorry for the poor resolution.
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Here is a close-up my OPA548 GC amp.
(http://groups.msn.com/_Secure/0TwDKAokWQWjy1kapSbQPium4zykN39*uwHXaW!a8w!1NKmKrVfT6EbRJMzVFDzwstGDWrXROySKlFjAhN8iNpY*8xieszrzi4cVaqafuyOG5eYIQ4CyDGA/OPA548%20Quad%20amp.jpg?dc=4675462418961546691)
Used an improvised heatsink for testing purpose only. I haven't bought a larger heatsink yet. I'm still thinking on what chassis to use.
Sorry for the poor resolution.
nice work sir :) . the parts are neatly laid out
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hi fastback,
congrats on ur gc. listening session na ba?
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Those heatsinks look very familiar! Looks like they're from a pc psu. ;D You can literally use that if you are not planning to listen at full blast all the time.
With a 5 channel sound card, coupled to a 5 channel gc, playing Ghost Recon would be like the real thing. :o
Congrats, keep it up.
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Congrats Fastback. Very nice work.
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FASTBACK,
Try not to change those heatsinks, I cooked up a 548 this afternoon and am now "torturing" >:( this mini gc using the same heatsink that you used, i got mine from one of my junk pc psu. If this one dies, this would be my first kill. ;D
JojoD
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Thanks guys.
JojoD
Yup yup you're right I got the heatsink from my old AT power supply and added an aluminum C-Channel. So far no problems with the amp. I haven't turned it off since I've connected it for testing.
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Thanks guys.
JojoD
Yup yup you're right I got the heatsink from my old AT power supply and added an aluminum C-Channel. So far no problems with the amp. I haven't turned it off since I've connected it for testing.
That's fine. break it in for a few more days and you'll see that things get better. ;)
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Magtatanong lang po....san ba nakakabili ng OPA549?
salamat po.......
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Magtatanong lang po....san ba nakakabili ng OPA549?
salamat po.......
meron yata nito sa Farnell o kaya sa RS components.
kung gusto mo ng libre, pwede ka order ng sample sa TI.
visit their website www.ti.com
register ka lang tapos request ka na ng samples.
good luck :)
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GC Guys
I've just finished another amp for my PC setup a bridge parallel based on the OPA2544 Op amp and another OPA548 based GC amp.
The OPA2544 to be used as a subwoofer amp and the OPA548 to be used as a center ch amp.
(http://groups.msn.com/_Secure/0awDVAjcemUL5Akn21BSg!HarxovU650EJNF0XMQGjUrI*tEStw34B*mBaWBza2ofh*pN3cc9C4xHUbsxL5PcaTgsZbBiB7V!ztSsdAY!OsFoF80JF878Y7NDysokxBC570qQIE0XHL800!YVGr2EGX8mtAJyrY61/OPA2544%20Bridge%20Parallel%20and%20OPA548%20GC.jpg?dc=4675462830621611164)
As usual I there is the ever trusted aluminum C-channel used as a heatsink for testing purpose only.
Thanks
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Excellent layout, how does it sound?
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The sound of the OPA2544 compared to the OPA548, I noticed the OPA548 has a prominent High frequency while the OPA2544 has a prominent Mid frequency. This is just my initial observation.
I am really surprised to hear such a simple circuit could sound that good. both for the single ended amp and a bridge parallel, and in the future I can make my way up to a more powerful chip.
Kawawa naman yung LM12 ko na shelf na naman siya, but I do have some parts for it but I like to make a PCB fo the project and would love to compare the different GC amps.
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The sound of the OPA2544 compared to the OPA548, I noticed the OPA548 has a prominent High frequency while the OPA2544 has a prominent Mid frequency. This is just my initial observation.
I am really surprised to hear such a simple circuit could sound that good. both for the single ended amp and a bridge parallel, and in the future I can make my way up to a more powerful chip.
Kawawa naman yung LM12 ko na shelf na naman siya, but I do have some parts for it but I like to make a PCB fo the project and would love to compare the different GC amps.
I believe that the LM12 has been in production before NS released their "Overture" series. For a while, LM12 was once NS's best bid in the chipamp market. Originally designed for motor controls (due to it's hi current capability), it's place in the audio market was blocked only be a single factor - it's high price. When I first heard an LM12 prototype, how I wish I had one. But that was a long time now. ;)
JojoD
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JojoD818
Sent u a PM.
Anyone know where to get a Cheap heatsink?
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JojoD818
Sent u a PM.
Anyone know where to get a Cheap heatsink?
Got your PM. Thanks! Maybe after I finish amp orders then I'll send you a PM too. I have so many amps to build and I am already behind schedule.
Alexan sells those black heatsinks, very good for GC projects.
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JojoD818
No problem there.
I'm on the process making a PCB for the next amp that I'm going to build. Still thinking of a design for the Casing for the 5.1 ch amp that I made.
Thanks
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my 2nd gc is almost finished!
it 2 channels, using the lm3875 chip
jojo, regarding the wiring of the volume pot and the input, they have the same connections right? well in my diagram, they seem to have the same wires. the question is how do you wire them up? the pot and the rca input has 3 binding posts. kahit anong order ba? or may order. pls help.
tnx
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my 2nd gc is almost finished!
it 2 channels, using the lm3875 chip
jojo, regarding the wiring of the volume pot and the input, they have the same connections right? well in my diagram, they seem to have the same wires. the question is how do you wire them up? the pot and the rca input has 3 binding posts. kahit anong order ba? or may order. pls help.
tnx
Medyo malabo description mo. ???
A pot has 3 terminals, with the control lever facing you, the first terminal (left) goes to the rca "hot", then the second terminal (middle) of the pot goes to your amp, while the third terminal (right) of the pot goes to ground. The ground of the rca jack must be connected to this ground using shielded wires. Now that is for mono, just repeat the procedure if you are using a stereo pot.
Good luck, and Godspeed to your GC!
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moonshow
Good luck on your GC.
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A more technical--should I say erudite--point of view. Don't understand most of it but the tips I find useful.
Why Gainclones Work
http://www.adx.co.nz/techinfo/audio/gainclone1.htm (http://www.adx.co.nz/techinfo/audio/gainclone1.htm)
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A more technical--should I say erudite--point of view. Don't understand most of it but the tips I find useful.
Why Gainclones Work
http://www.adx.co.nz/techinfo/audio/gainclone1.htm (http://www.adx.co.nz/techinfo/audio/gainclone1.htm)
Very interesting indeed!
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A more technical--should I say erudite--point of view. Don't understand most of it but the tips I find useful.
Why Gainclones Work
http://www.adx.co.nz/techinfo/audio/gainclone1.htm (http://www.adx.co.nz/techinfo/audio/gainclone1.htm)
This is an interesting piece of information supported by critical measurements. Somehow, the comment of ramble_on and Jojod818 earlier in this thread, and this piece of information point to a common concept, that this LM gainclones matched the characteristics of the tube amps, eliminating not only the odd harmonics, as well as even harmonics. Further, this gainclones present a higher power at lesser cost, but comparable sound characteristics that tube afficionados run for! It also consumes less energy as well.
Based on this information, I am now bent to build one for me. I do agree with the writer that in fact National Semicon engineers indeed made a good job in the design of this gainclones!
Sometimes, the best things in life is not the costly ones!
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joe rasmussen claims his hybrid gainclone outperforms many fully tubed designs, and is even comparable in performance to many single-ended triode amps... he has commercialized it into the vacuum state electronics JLTi integrated amp (http://members.ozemail.com.au/~joeras/jlti_photos.htm).
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joe rasmussen claims his hybrid gainclone outperforms many fully tubed designs, and is even comparable in performance to many single-ended triode amps... he has commercialized it into the vacuum state electronics JLTi integrated amp (http://members.ozemail.com.au/~joeras/jlti_photos.htm).
yep but its relatively expensive though :)
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john, natanong mo na kay master andrew kung kaya niya gawin yun JLTi ? mukhang may links din ito sa schematics... parang napaka-simple, the gc itself is only taking up one-sixth of the space inside the chassis.
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Akyat, no i haven't pero i think the commercial version has some added "tweaks" not found in the schematics. and the commercial version uses botique parts too i think :)
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Gentlemen,
I have built that one and to be honest, I have been tweaking it for three months now. I started the project last December 2003 when a "tube addict friend" mugged me to build one for him ;D.
According to him, this hybrid gainclone prototype that I built really sounds excellent even with non-exotic parts. After I finalize the component selections and prototyping of this hybrid, maybe I can accept custom jobs ;). But not yet, I still have an RIAA tube preamp to build for another buddy. 8)
Regards,
JojoD
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jojod18, just goes to show that the design is very good to begin with :)
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jojod18, just goes to show that the design is very good to begin with :)
Nothing fancy, just a cathode follower configured tube and that's it ;). Something similar to the final stage of the Foreplay preamp of Bottlehead. It was implemented so as not to disturb the global feedback of the gainclone when subjected to different pot settings (very clever indeed). Plus of course, it comes with all the goodies (and maybe also the bad) of tubes.
All I can say is that the sound is fantastic! A "brusko" sounding LM3875! I hope to finish and deliver the project in two weeks time, and then I'll post pics. :)
JojoD
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any rough estimate on parts cost?? assuming you have to buy a pair of lm3875s?
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any rough estimate on parts cost?? assuming you have to buy a pair of lm3875s?
I haven't made a bill of materials yet so I still have no idea on the final cost for the project. I'm sure the cost wouldn't be that much. ;)
JojoD
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jojo
can you modify my lm3875 ampd to have that tube hybrid part?
also, where do u get your chasis? my gainclone still doesn't have a suitable case.
tnx
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Jojo
Did you notice the difference between the OPA548 and the OPA549 in terms of output level?
I've just finished building an OPA549 though I haven't tested it higher volume. I also used an inverting configuration for it.
Going to try a non-inverting to compare the difference between them.
Thanks
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jojo
can you modify my lm3875 ampd to have that tube hybrid part?
also, where do u get your chasis? my gainclone still doesn't have a suitable case.
tnx
Yes I can. I buy the chassis pre-made, I just drill the holes.
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Jojo
Did you notice the difference between the OPA548 and the OPA549 in terms of output level?
I've just finished building an OPA549 though I haven't tested it higher volume. I also used an inverting configuration for it.
Going to try a non-inverting to compare the difference between them.
Thanks
The 548 is a formidable chip that can handle itself. All it needs is a suitable heatsink, a fairly large one. It's like a cross between the old LM383T and the TDA2050 ;D. BB of TI likes to make gc chips with the best of both worlds packed in it.
As a rule, I always start non-inverting, then tweak, then build another one in inverting mode.
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Jojp
I'll try to make a non-inverting one for comparison.
Thanks
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Jojp
I'll try to make a non-inverting one for comparison.
Thanks
The sound of a non-inverting and inverting gc is a subjective matter. Use what pleases your ears my friend.
JojoD
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Gentlemen,
I have built that one and to be honest, I have been tweaking it for three months now. I started the project last December 2003 when a "tube addict friend" mugged me to build one for him ;D.
According to him, this hybrid gainclone prototype that I built really sounds excellent even with non-exotic parts. After I finalize the component selections and prototyping of this hybrid, maybe I can accept custom jobs ;). But not yet, I still have an RIAA tube preamp to build for another buddy. 8)
Regards,
JojoD
Hello JojoD,
One can't avoid making tough decisions in life. :( Tough decisions like whether to use flat or rounded mains cord, mylar or polyprops, etc. Now, I am confused if I'd still consider you a friend after you broke our code of omerta (silence).
Written in blood of your fingers, we vowed to keep this project top secret. How dare you squeal? >:(I will avenge by revealing these fallacies in your post:
1. "tube addict friend" - I am no addict; I own a PP (EL34) and a SET Amp (2A3). Have a few spare tubes for contingencies but that's it. But I do love the sound of tube amps. Does that give anyone a reason, and a friend at that!!!, to call me an Addict? JojoD, that is unfair. :o
2. non-exotic parts - No, these are not non-exotic parts. Excuse me, but these are Raon-grade parts. Some are even used ones. I believe in the law of "Diminishing Returns". I change the parts, value and type/composition per my personal taste or what I perceive as more "hi-fidelity". And I don't have the fat wallet to do so using pricey exotic parts. Maybe, I will do that later when I am "solved" with the value/composition-based experiments or when I realize the need for it. JojoD, be careful with your words. i can report you to mod for disparaging remarks. :P
3. sounds excellent - a subjective/relative statement yet all I can say: my confidence remained intact and soaring after I heard this amp sing, in the same test environment, against my tube amps, a friend's commercial 2A3-amp+pre combo, commercial hifi SS stereo, SS receiver, standard LM3875 GC, Rod Elliot's P3A, another friends DIY-kit SS Amp (from a popular vendor). Does that make it excellent sounding? If you include cost of ownership (exclusing JojoD's bloody fingers), then definitely. :P :P :P
*commercial brands omitted on purpose. brands do blind the ears which should be used for evaluative listening.
4. After I finalize the component selections and prototyping of this hybrid, maybe I can accept custom jobs - don't blame this project if you can't replicate what you did. You're so driven to make it sound so good (even ambitioning to do better than published circuitry) and in the process busted your fingers. All i wanted was a 5-channel custom amps for HT and you gave me an amp that has the muscle of SS and warmth of tubes! You should learn to fathom user specification! ::)
Guys, forgive this ka-cornihan :) :'((just having a little fun here). There is no one else to blame for this euphoria but the man himself. JojoD is the man!
I dreamt, I hoped, I begged and mugged... and jojoD delivered! ;D Now here's a tougher decision: which should I listen to on MWF, conventional tube amps or tubed GC? Why not on TThS? E, yg non-tubed gc? 8)
DIY is fun, esp if an expert is DIYing for you! 8) 8) 8)
P.S. JojoD, for your abused fingers, I will donate something cold. Like a cold botte of wine you can hold on to? How's that for celebration? :D
P.S. again: Parang end-credits ito, but seriously to Joan, thank you for the Gainclone inspiration kung saan ka man naroroon. What was necessitated by ka-kakuriputan ended up very well! ;) :) (Necessity is the mother of invention.)
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ha ha ;D You're tubed GC must sound so good to write a longish tribute to JojoD! Details please! Congrats to you and hats off to JojoD.
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nice! haha... ;D i've always been a lurker in this thread, and it seems what i've been waiting for will someday become a reality -- that the DIY will soon become a DI4U... that is some roster of amps that you tested it against... hooray to jojoD & eXg for the successful project. ;D ;D
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OK, then, let's start the ball rolling!
If I place an order for 6-channel amplifier, broken as 3 chassis of 2-channel each . . .
How much?
I love this idea of DIY4U!!!
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Hello JojoD,
One can't avoid making tough decisions in life. :( Tough decisions like whether to use flat or rounded mains cord, mylar or polyprops, etc. Now, I am confused if I'd still consider you a friend after you broke our code of omerta (silence).
Written in blood of your fingers, we vowed to keep this project top secret. How dare you squeal? >:(I will avenge by revealing these fallacies in your post:
1. "tube addict friend" - I am no addict; I own a PP (EL34) and a SET Amp (2A3). Have a few spare tubes for contingencies but that's it. But I do love the sound of tube amps. Does that give anyone a reason, and a friend at that!!!, to call me an Addict? JojoD, that is unfair. :o
2. non-exotic parts - No, these are not non-exotic parts. Excuse me, but these are Raon-grade parts. Some are even used ones. I believe in the law of "Diminishing Returns". I change the parts, value and type/composition per my personal taste or what I perceive as more "hi-fidelity". And I don't have the fat wallet to do so using pricey exotic parts. Maybe, I will do that later when I am "solved" with the value/composition-based experiments or when I realize the need for it. JojoD, be careful with your words. i can report you to mod for disparaging remarks. :P
3. sounds excellent - a subjective/relative statement yet all I can say: my confidence remained intact and soaring after I heard this amp sing, in the same test environment, against my tube amps, a friend's commercial 2A3-amp+pre combo, commercial hifi SS stereo, SS receiver, standard LM3875 GC, Rod Elliot's P3A, another friends DIY-kit SS Amp (from a popular vendor). Does that make it excellent sounding? If you include cost of ownership (exclusing JojoD's bloody fingers), then definitely. :P :P :P
*commercial brands omitted on purpose. brands do blind the ears which should be used for evaluative listening.
4. After I finalize the component selections and prototyping of this hybrid, maybe I can accept custom jobs - don't blame this project if you can't replicate what you did. You're so driven to make it sound so good (even ambitioning to do better than published circuitry) and in the process busted your fingers. All i wanted was a 5-channel custom amps for HT and you gave me an amp that has the muscle of SS and warmth of tubes! You should learn to fathom user specification! ::)
Guys, forgive this ka-cornihan :) :'((just having a little fun here). There is no one else to blame for this euphoria but the man himself. JojoD is the man!
I dreamt, I hoped, I begged and mugged... and jojoD delivered! ;D Now here's a tougher decision: which should I listen to on MWF, conventional tube amps or tubed GC? Why not on TThS? E, yg non-tubed gc? 8)
DIY is fun, esp if an expert is DIYing for you! 8) 8) 8)
P.S. JojoD, for your abused fingers, I will donate something cold. Like a cold botte of wine you can hold on to? How's that for celebration? :D
P.S. again: Parang end-credits ito, but seriously to Joan, thank you for the Gainclone inspiration kung saan ka man naroroon. What was necessitated by ka-kakuriputan ended up very well! ;) :) (Necessity is the mother of invention.)
Hi!
;D You got me! I'm so sorry for breaking silence... I was just so excited that I forgot about that agreement. :D
Now to make you more happy, I just finished your non-tubed, inverting LM3875 Boso Amp on kamagong! Your surround speakers better be ready.
I am looking forward on busting my fingers (again?) in your heavily modified tubed gainclone. Cold wine and some band-aid please. ;D
JojoD
(http://img23.photobucket.com/albums/v70/jojod818/Boso%20Amp%20Non-Tubed/Pic001.jpg)
(http://img23.photobucket.com/albums/v70/jojod818/Boso%20Amp%20Non-Tubed/Pic002.jpg)
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I was looking for some bermuda grass as a background but can't find one. ;D ;D
(http://img23.photobucket.com/albums/v70/jojod818/Boso%20Amp%20Non-Tubed/Pic004.jpg)
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OK, then, let's start the ball rolling!
If I place an order for 6-channel amplifier, broken as 3 chassis of 2-channel each . . .
How much?
I love this idea of DIY4U!!!
Thank you for the interest in this endeavor, I will post the price as soon as I finish the tubed version.
I was thinking of two prices, one with non-exotic parts, and another for pricey parts. But don't be fooled by the non-exotic parts, they maybe cheap but they do sound great.
Regards,
JojoD
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I have finished building an OPA549 amp non-inverting configuration and doing the testing right now.
It is still early to say the difference between the Inverting and non-inverting since I need to listen to it over a long period.
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Jojo, thanks for completing the reference version (non-tubed). I hope it will sound nicer on its hardwood bed.
Hubad na, nasa kama (as in kamagong) pa! ;D
Guys, I am not very good at writing what my ears perceive. :(Besides, what is good to me may be crap to another. Individual setup matters, too. So, I hope you will settle with this: It's a project worth your while. JojoD perhaps can provide more techie details.
Instead, allow me to share my personal objectives on this project: inexpensive/reasonable, maintainable by me (clumsy DIYer that I am), few parts, and competitively nice sounding. In my yardstick, those standards are met. ;D
I took the route which allowed me (yehey nakapag solder na ako) some customiziing on the sonic character of this amp. In other words, my personal preference shaped the sonic character of this amp. (Sa totoo lg parang endless journey ito.)
And this is what I like about this: learning a little something along the way. (At 'yan pa ang ayaw ko kay JojoD, you throw him a simple question, he will give you a lecture! Tama ba naman yan? Being an electronics-illiterate, I can only hope for answers to come in black-and-white simplicity. :) :) :)) In fairness, he lays down pros-and-cons, and you can choose or take his expert advise. :D
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Jojo, thanks for completing the reference version (non-tubed). I hope it will sound nicer on its hardwood bed.
Hubad na, nasa kama (as in kamagong) pa! ;D
Guys, I am not very good at writing what my ears perceive. :(Besides, what is good to me may be crap to another. Individual setup matters, too. So, I hope you will settle with this: It's a project worth your while. JojoD perhaps can provide more techie details.
Instead, allow me to share my personal objectives on this project: inexpensive/reasonable, maintainable by me (clumsy DIYer that I am), few parts, and competitively nice sounding. In my yardstick, those standards are met. ;D
I took the route which allowed me (yehey nakapag solder na ako) some customiziing on the sonic character of this amp. In other words, my personal preference shaped the sonic character of this amp. (Sa totoo lg parang endless journey ito.)
And this is what I like about this: learning a little something along the way. (At 'yan pa ang ayaw ko kay JojoD, you throw him a simple question, he will give you a lecture! Tama ba naman yan? Being an electronics-illiterate, I can only hope for answers to come in black-and-white simplicity. :) :) :)) In fairness, he lays down pros-and-cons, and you can choose or take his expert advise. :D
You're welcome. 2 more days and you'll have yourself a 3 channel hybrid.
P.S. Yan ha, short reply lang, walang lecture! ;D
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I have finished building an OPA549 amp non-inverting configuration and doing the testing right now.
It is still early to say the difference between the Inverting and non-inverting since I need to listen to it over a long period.
What chip are you comparing the 549 with? How does it sound?
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What chip are you comparing the 549 with? How does it sound?
JojoD818
I am comparing the 549 Inverting and Non-inverting configuration to determine if there are any difference in sound quality. Presently I could not distinguish any difference.
I am using a Car audio CD selection to burn in the GC amp.
The Non-inverting GC I include a zobel network while the Inverting has none. The gain for the Inv is 22 and Non-inv is 23.
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JojoD818
I am comparing the 549 Inverting and Non-inverting configuration to determine if there are any difference in sound quality. Presently I could not distinguish any difference.
I am using a Car audio CD selection to burn in the GC amp.
The Non-inverting GC I include a zobel network while the Inverting has none. The gain for the Inv is 22 and Non-inv is 23.
Maybe it's a good idea to break them in first before comparison.
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eXg,
Just finished the hybrid tube gainclone! At first, I thought I was so tired from working all day long on it but when I hooked it up, I smiled. ;)
I hope you like this one.
(http://img23.photobucket.com/albums/v70/jojod818/Boso%20Amp%20Tubed/Pic00147.jpg)
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(http://img23.photobucket.com/albums/v70/jojod818/Boso%20Amp%20Tubed/Pic00146.jpg)
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Grrrrr.... (gigil, tulo laway :P :P :P).... I love how they look! Sexy and enticing. 8) When can I have my Boso monoblocks ("integrated")?????
Can't believe how you make them up in 1-week! It can very well compete it's Loftin-white layout inspiration!
Thank you. Thank you.Thank you.Thank you.Thank you.
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Grrrrr.... (gigil, tulo laway :P :P :P).... I love how they look! Sexy and enticing. 8) When can I have my Boso monoblocks ("integrated")?????
Can't believe how you make them up in 1-week! It can very well compete it's Loftin-white layout inspiration!
Thank you. Thank you.Thank you.Thank you.Thank you.
May I suggest you take them off my hands asap? I don't want to be too comfortable to their sound.
(http://img23.photobucket.com/albums/v70/jojod818/Boso%20Amp%20Tubed/Pic00148.jpg)
Do you see the 3rd unfinished one?
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sir jojoD, ako rin interested dyan ha kung may time ka na mag custom job... ;D pa-pm or email nung price... ;)
kakainggit ang ganda! ;D
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ang GANDA!!!! :D :D
hybrid mono-blocks, sana madinig namin... please?
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Sir,
Pa pm din nung price. :)
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ang GANDA!!!! :D :D
hybrid mono-blocks, sana madinig namin... please?
Am ok with this! JojoD, what do you think? Been looking forward to compare this amp with others, other than my own para naman ma-improve pa (if necessary). BTW, these amps/blocks are built for HT with scalability in mind (quality of stereo comes as bonus to me :)).
Will pick up asap. Listen as much as you can 'coz you will miss them for quite some time. My Jurassic and Private Ryan DVDs are waitiing to break these again. ;D
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great! kung ok lang kay Akyat, sa saturday na ;D
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uy ok na ok yan, more than ok! ;D
kung sakali sa all-tube setup meron tayong (sana) kt88 monoblocks, 6550 set, with tono & pono preamp, ano pa nga ba... sa solid state naman meron (kung sinipag ikabit) musical fidelity, marantz, kenwood, sansui & accuphase.
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akyatbundok, 7Even,
You have PM.
JojoD
(http://img23.photobucket.com/albums/v70/jojod818/Boso%20Amp%20Tubed/Pic00156.jpg)
P.S. eXg, This things really rock! Also made a CAT5 speaker cable and sounded really warmish.
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grrrr gusto ko din! ;D magbebenta na ulit ako ng gamit hehe ;D
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may I also ask how much one of these will cost? also will tube rolling affect the sound?
thanks!
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may I also ask how much one of these will cost? also will tube rolling affect the sound?
thanks!
Sent you PM.
I only tried JAN Phillips and Sylvania tubes with great results.
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JojoD818
Galing talaga. I'm also begining to get interested about Tubes. The only encounter that I have about tubes is that when I was a kid all our television are made of tube components and whenever it got busted we have alot of spare tube lying around.
Here I go again I better search for those tubes maybe there is one that I can use for audio.
Question.
Are those tubes locally available?
How much?
Again keep up the good work.
Thanks
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Akyat/Icem,
Sorry but can't make it this weekend. I don't know abt JojoD tho.
It's a case of having two little kids, no househelps and a partner doing nothing to help with chores but listening to your stereo setup all day long... you know what I mean? ;) :)
tambak sa labada :'( :'( :'(
Fastback, marami pg tubes dito sa atin. Prices vary depending on type and brand/age. Do drop by at phasetron in makati (see AMX amps thread) to check some tubes.
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(http://img23.photobucket.com/albums/v70/jojod818/Boso%20Amp%20Tubed/Pic00156.jpg)
Galing mo talaga sir JojoD. Pm mo naman how much it cost and parts sourcing :)
Subukan ko din bumuo ;D
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Fastback, marami pg tubes dito sa atin. Prices vary depending on type and brand/age. Do drop by at phasetron in makati (see AMX amps thread) to check some tubes.
eXg
Thanks for the info.
will check the store you recommend, I knew before there is a store in raon that sells tubes not sure if they are still in business, will check it out also one of these days.
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I am interested to buy, how much will each assembled unit cost? can you pm me the price also.
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Sir JojoD, pm
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Sir JojoD, pm
Sent you a PM.
Guys, please drop the "Sir" ;D We are all hobbyist (correct ba spelling?) in this field so we are all like apprentices.
I encourage all of you to DIY. I may be building the amp for you, but the project has so much room for tweaks which you yourself can do.
Cheers!
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JojoD
I already found my dad's stash of tubes unfortunately most of the tubes have a white mist inside it, asked him about it and he said it is already damaged. so I separated the tubes that is physically good, but still have to test it though if it is electronically good.
So here is my question
1. The tube used for the design is a medium mu twin triode, can I use just a twin triode part # 4HA7 on the design ?
2. Since the 6922 is a medium mu twin triode, one tube can be used for a stereo Gainclone. ?
3. I really don't know what the Medium mu, High mu stands for and what are their difference?
4. Can you sent me a PM regarding the price of the tube.
Thanks in advance.
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The tube 6922 was also used in the AOpen AX4B-533 Tube Motherboard.
Can this be used other than the LM3875 Gainclone ?
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JojoD
I already found my dad's stash of tubes unfortunately most of the tubes have a white mist inside it, asked him about it and he said it is already damaged. so I separated the tubes that is physically good, but still have to test it though if it is electronically good.
So here is my question
1. The tube used for the design is a medium mu twin triode, can I use just a twin triode part # 4HA7 on the design ?
2. Since the 6922 is a medium mu twin triode, one tube can be used for a stereo Gainclone. ?
3. I really don't know what the Medium mu, High mu stands for and what are their difference?
4. Can you sent me a PM regarding the price of the tube.
Thanks in advance.
Am not sure to the answer to question 1, don't have datasheet for 4HA7.
No. 2 = Yes
No. 3 = MU = Amplification factor. Hi MU = Higher gain.
No. 4 = You can buy at Phasetron or any other audio shops, it costs around 550 up.
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The tube 6922 was also used in the AOpen AX4B-533 Tube Motherboard.
Can this be used other than the LM3875 Gainclone ?
As long as it is a 6922=6DJ8=ECC88, yes. ;D
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JojoD818
Thanks you have been very helpful.
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JojoD818
Thanks you have been very helpful.
That's one of the things I learned from my parents. ;)
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(http://img23.photobucket.com/albums/v70/jojod818/Boso%20Amp%20Tubed/Pic00156.jpg)
Galing mo talaga sir JojoD. Pm mo naman how much it cost and parts sourcing :)
Subukan ko din bumuo ;D
Sorry, I don't have a complete list of the parts right now. This project is an ever continuing experiment. As an example, my next 2-channel hybrid (for a friend) will include a new PSU design, higher voltage (tubes loves this) that is supposed to improve dynamics and headroom. It even includes a speaker turn-on delay for taking care of those nasty thumps. You see, it is so fluid.
Cheers!
JojoD
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Sorry, I don't have a complete list of the parts right now. This project is an ever continuing experiment. As an example, my next 2-channel hybrid (for a friend) will include a new PSU design, higher voltage (tubes loves this) that is supposed to improve dynamics and headroom. It even includes a speaker turn-on delay for taking care of those nasty thumps. You see, it is so fluid.
Cheers!
JojoD
No problem ;D. Anyway i still have some GC projects to work on. Just acquired a pair of 15" Thump subwoofers and starting to do some parts soldering for one subwoofer. will be using OPA549 in bridge+parallel mode with low pass filter schematics copied on your web :). will post pics once finished.
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No problem ;D. Anyway i still have some GC projects to work on. Just acquired a pair of 15" Thump subwoofers and starting to do some parts soldering for one subwoofer. will be using OPA549 in bridge+parallel mode with low pass filter schematics copied on your web :). will post pics once finished.
Good luck on your sub project! Just a reminder, try to beef up your PSU especially the trafo since the chips would draw a huge amount of current or they will clip. >:(
I haven't updated my website recently but all circuits in the website are still up and running.
Cheers!
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JojoD,
Thanks actually i will be using a 12 amp. transformer and a pair of General Electric "coke can" size 33,000 microFarad caps for the PSU :)
Have tried these pair of caps on my stereo GC and it has lots of reserve. at moderate level, i can switch off the power amp and hear at least 8 seconds of undistorted sound ;D
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JojoD,
Thanks actually i will be using a 12 amp. transformer and a pair of General Electric "coke can" size 33,000 microFarad caps for the PSU :)
Have tried these pair of caps on my stereo GC and it has lots of reserve. at moderate level, i can switch off the power amp and hear at least 8 seconds of undistorted sound ;D
Using huge caps on gcs fairly has any effect on the sound as I have also tried them before (GE, Mallory, Nichicon, ELNA). But for sub apps, it would feel good to know that you have extra capacitance. However, what's important is the trafo, it must have very good regulation to be able to hold it's output voltage constant. Huge caps only help for a short period of time, besides, you'll be affected by the "law of diminishing returns".
Cheers!
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Finally I was able to test tubes that I separated. I have several Triode on hand that is good and I am now searching the net for it's datasheet to determine if I could experiment on this to be used on a Tube Gainclone.
Hehehe good thing we still have our Tube Television lying around, will use is to scavenge the parts I need.
Finished the OPA549 inverting and non-inverting GC I am going to do a bridge-parallel, this will be used to power my 2 12in subwoofer.
JojoD
Can I copy the circuit of the crossover you made ?
Thanks
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JojoD
Can I copy the circuit of the crossover you made ?
Thanks
Sure, enjoy!
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Monsieur JojoD (o di Sir yan h ;Da),
So far k pa naman yg GCs ko -- alive and kicking. (it's literally kicking around my 90db fullrange DIY HT speakers).... :'( :'(, i miss my 87dbs speakers.
A few friends came over to hear a 5687-based line preamp with a mid-level yamaha receiver. i thought the sound was sonorous but they preferred the Boso Monoblocks anyway. :) Hmmm, rock rules!
I am looking forward to hearing the Bosos against 3 or 2 way speakers at around 85dbs!
???Esep-esep for new GC-based project. RIAA??? SubW?
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Monsieur JojoD (o di Sir yan h ;Da),
So far k pa naman yg GCs ko -- alive and kicking. (it's literally kicking around my 90db fullrange DIY HT speakers).... :'( :'(, i miss my 87dbs speakers.
A few friends came over to hear a 5687-based line preamp with a mid-level yamaha receiver. i thought the sound was sonorous but they preferred the Boso Monoblocks anyway. :) Hmmm, rock rules!
I am looking forward to hearing the Bosos against 3 or 2 way speakers at around 85dbs!
???Esep-esep for new GC-based project. RIAA??? SubW?
;D Di nga sir mas matindi naman. ;D ;D
Nice to hear your enjoying those GCs. Sub project? Bridge-Parallel GCs na yan! ;D Yun TDA7293/4 (Drunk GC ;D ;D ;D, lasengo kasi designer kaya ang gulo ng pin config >:() will be a sure winner.
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Finished the OPA549 inv and non-inv bridge parallel.
presently doing the burn in of the GC amp.
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Finished the OPA549 inv and non-inv bridge parallel.
presently doing the burn in of the GC amp.
Pics?
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jojo, when you're ready, let's have a little session at home. i really want to listen to your masterpiece and compare them with other PP amps.
more power to DIY!
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jojod
will post some pics soon. having problem with my computer lately.
I finished the testing of all the tubes I have, and fortunately there are some tube that can be used as a preamp, hope to build one soon and connect it to a GC amp.
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jojo, when you're ready, let's have a little session at home. i really want to listen to your masterpiece and compare them with other PP amps.
more power to DIY!
Sure! No problem. Just Need to finish some amps I'm doing right now.
Regards,
JojoD
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jojod
will post some pics soon. having problem with my computer lately.
I finished the testing of all the tubes I have, and fortunately there are some tube that can be used as a preamp, hope to build one soon and connect it to a GC amp.
Good for you, maybe those tube costs a lot now since they are very old. ;)
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I really hope I could build a good preamp with those tube that I got.
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Here are some pics of my OPA549 Bridge Parallel GC.
(http://groups.msn.com/_Secure/0UgAxAyMYXulI98L7TcI8Y6WBastKcCSNMKzdNtrQoTRfC9gyYTSBxxKb1*eiTycrKtnPj46GQru8oEQcvpKknNcPbG5PfA9RumdBcaNrSAUoXZN4rd0xaBjFv4!yo6LO/Bridge%20Parallel%2003.jpg?dc=4675466397877331980)
Left Side is a Non-inv bridge parallel the right side is an Inv bridge parallel. As usual still no casing still looking for one. Will add a low pass filter soon and use it for my sub's.
(http://groups.msn.com/_Secure/0SQDhAsYVNCWSFAcDJeNuz2!P1yot70p35UAFORhbkKcJDt5DP1Rfz48UkudzSVN3V8HRcjG7BuQXThB9P!H67pfmz!GUkKNAxD9UKlwUZfSUWJC5f5ookA/Tube%20Tester.jpg?dc=4675466397985899209)
Pic of my Dad's tube tester. The tube being tested is a 12AX7A tube. good thing that my dad kept it in a safe place.
(http://groups.msn.com/_Secure/0SgDiAicVkfzUmLIktUyPBpddWd5r5jDFWp0QduEZk0nHSbR!TFySOPgkqC72VY6xsxO9oqR*ZMgxrYzz6qOQTaQhGdwd1h9s4mrjUAoopvlXxh3QR2f7ag/12BH7A%20Tubes.jpg?dc=4675466397539477126)
12BH7A tubes, Hope to build myself a pre-amp and connect it to a GC amp using thse tubes since I already have them.
Please excuse the low resolution of the pics.
Thanks.
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FASTBACK,
congrats on your latest GC projects :)
have you compared the sound of the inverting and non-inv GCs?
presently building an inverting bridge-parallel amp with low pass filter but taking me quite a long time to finish. Kailangan muna na magtrabaho ;D
will post pics later
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Using huge caps on gcs fairly has any effect on the sound as I have also tried them before (GE, Mallory, Nichicon, ELNA). But for sub apps, it would feel good to know that you have extra capacitance. However, what's important is the trafo, it must have very good regulation to be able to hold it's output voltage constant. Huge caps only help for a short period of time, besides, you'll be affected by the "law of diminishing returns".
Cheers!
oops hindi pala siya 33,000 but 32,000 microFarads ;D
actually, hindi naman ito expensive coz its a surplus. got the pair for P300. :)
(http://groups.msn.com/_Secure/0QgDfAgcTPmzQhzK21CDlfAF6TgwDGyGVF8iLgJOk3rTXucltv!z3tFo7QZa9KYQ70Tvk4GvH2ap0GQAz7fckGRxd8Vf7ZQU6w2ItmtIKUcQ/GEcaps.JPG?dc=4675466446868358432)
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FASTBACK,
congrats on your latest GC projects :)
have you compared the sound of the inverting and non-inv GCs?
presently building an inverting bridge-parallel amp with low pass filter but taking me quite a long time to finish. Kailangan muna na magtrabaho ;D
will post pics later
unfinished bridge-parallel w/ low pass filter
(http://groups.msn.com/_Secure/0TQAxAycXK5LttIg6rIHkQ0j9xnohZLUy2eFcilHmZvopZkjsc5jyo6MHWnzSGfNwjbaQw3dsVPFb7hr4R7yrALds!cghPeBHoOWKGcOnDrufU0OFOA9J4A/bridge%2Bparallel.JPG?dc=4675466450182848324)
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nice work!
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homer, thanks :)
hope it works ;D
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homer, thanks :)
hope it works ;D
Trust me it will. ;)
I use the low pass in my website for my bridge parallel powered subs. 8)
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rmpmla
Nice work there.
Regarding the comparison between the two inv and non inv, I cannot determine any difference. all I can say is that this bridge parallel rocks.
Some changes I made in the non inv I removed the input cuopling capacitor. while the inv has the inverting caps.
on the DRV134 I did not connect the sense pins as indicated in the schematics. I noticed that the power out is higher.
Try to experiment on your GC to arrive at your preffered setup.
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I experimented on the LM12 IC that I have, I did not use the recommended circuit by National Semi. works just fine, also sounds good.
I used a inv input with a gain of 10, very basic design, used my +/-18Vdc test power supply.
Will try other gain for this IC, I'll keep you posted.
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Used a gain of 22 and it works like a charm no problems encountered.
I am now finalizing the wiring of the amp.
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Finished 2 channel Hybrid gainclone pics...
(http://img23.photobucket.com/albums/v70/jojod818/Tube%20Hybrid%20GC%202%20Channel/Hybrid02-02.jpg)
(http://img23.photobucket.com/albums/v70/jojod818/Tube%20Hybrid%20GC%202%20Channel/Hybrid02-03.jpg)
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Kakainis yun DC offset oh, 0.00V! :o :P ;D
(http://img23.photobucket.com/albums/v70/jojod818/Tube%20Hybrid%20GC%202%20Channel/Hybrid02-01.jpg)
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Break-in period is a pleasure.
(http://img23.photobucket.com/albums/v70/jojod818/Tube%20Hybrid%20GC%202%20Channel/Hybrid02-07.jpg)
(http://img23.photobucket.com/albums/v70/jojod818/Tube%20Hybrid%20GC%202%20Channel/Hybrid02-08.jpg)
(http://img23.photobucket.com/albums/v70/jojod818/Tube%20Hybrid%20GC%202%20Channel/Hybrid02-05.jpg)
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Kakainis yun DC offset oh, 0.00V! :o :P ;D
Sir Jojo so this means 0 leakage(walang feedback current ? ;D .....at di madali mag-init ;D...congrats sir....LENNGGA!
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Sir Jojo so this means 0 leakage(walang feedback current ? ;D .....at di madali mag-init ;D...congrats sir....LENNGGA!
I sure hope that is what it means. ;D Seriously, I am having a great time listening to these amps. Sadly, them amps will be out of my hands soon. :'(
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and into mine hehehe yahoo! ;D ;D ;D galing mo sir jojo a.k.a. "master, teach me kung-fu"!! it was easy to spot your skills & talent after you posted pics of your work... inabot lang naman ng ilan buwan hintay before somebody was willing to do it for a DIY ("damage-it-yourself") guy like me... nels76 coined the term for me when i was telling him it took me 10 seconds to burn the PCB of a spy radio kit i was building after graduation. ;) ;D 8)
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and into mine hehehe yahoo! ;D ;D ;D galing mo sir jojo a.k.a. "master, teach me kung-fu"!! it was easy to spot your skills & talent after you posted pics of your work... inabot lang naman ng ilan buwan hintay before somebody was willing to do it for a DIY ("damage-it-yourself") guy like me... nels76 coined the term for me when i was telling him it took me 10 seconds to burn the PCB of a spy radio kit i was building after graduation. ;) ;D 8)
Uuuyy! another reason to make a pilgrimage to the mountain ;D
sama kami ha
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Uuuyy! another reason to make a pilgrimage to the mountain ;D
sama kami ha
Hahaha! Ayus yan term mo ah, napapanahon!
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Nice one again JojoD! :D
CONGRATS 8)
Kakainis yun DC offset oh, 0.00V! :o :P ;D
(http://img23.photobucket.com/albums/v70/jojod818/Tube%20Hybrid%20GC%202%20Channel/Hybrid02-01.jpg)
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JojoD
Nice work inggit naman ako, I hope someday makagawa din ako ng tube gainclone, still looking for a suitable Power supply design for my 12BH7A tubes, I already got a design for the preamp .
Meanwhile here is my finished LM12 GC, I am going to use this chip for a Tube gainclone amp. hope it works fine.
(http://groups.msn.com/_Secure/0WgDyAl8ZKW3oW*NfooC7NOhdGd1Hf2lqlmRI29FfhbVpT6xwbrHV07iDjzp0x0tNG58Ml58DQd9qFk167eLRXjsN0D0FQJonO0ola!2rPnz5HZMm*!dxqixzXZVJYRdXrBIqOoGOC84/LM12%204Ch%20Gainclone%20N.jpg?dc=4675466960528360449)
(http://groups.msn.com/_Secure/0WwDdAoMZyn3oW*NfooC7NOhdGd1Hf2lqlmRI29FfhbVc2zrOkqTk7LbY0tiY17eo3sQGPbQiDaT8gn7DKbLq0CZRf5Bo3yh5SDsDKmp2IEsCbYd5SzF!OZwJu0HQhfvLSmTBQMlOh!k/LM12%204Ch%20Gainclone%20A1.jpg?dc=4675466960676622721)
Thanks
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Kakainis yun DC offset oh, 0.00V! :o :P ;D
(http://img23.photobucket.com/albums/v70/jojod818/Tube%20Hybrid%20GC%202%20Channel/Hybrid02-01.jpg)
JojoD
Parang pareho kayo ng reading dito ha. Galing naman.
http://www.decdun.fsnet.co.uk/gainclone3.html#testing (http://www.decdun.fsnet.co.uk/gainclone3.html#testing)
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FASTBACK,
Galing LM12 mo ah! It would have been nicer if you have designed a pcb that holds the TO-3 opamp for a more shorter path especially for the supplies which causes spurous oscillations. Yan kasi nabasa ko sa National Semi about that chip. Pero kung ok naman then ayus!
Sidenote: 2:10AM na di pa din ako makatulog, sarap kasi pakinggan ng hybrid...
JojoD
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and into mine hehehe yahoo! ;D ;D ;D galing mo sir jojo a.k.a. "master, teach me kung-fu"!! it was easy to spot your skills & talent after you posted pics of your work... inabot lang naman ng ilan buwan hintay before somebody was willing to do it for a DIY ("damage-it-yourself") guy like me... nels76 coined the term for me when i was telling him it took me 10 seconds to burn the PCB of a spy radio kit i was building after graduation. ;) ;D 8)
This one is yours (one at the bottom)... :'(
The other one is also a hybrid, kaso for another friend din. Wawa naman ako... oks lng may Prerotica naman! Hahahaha
(http://img23.photobucket.com/albums/v70/jojod818/Tube%20Hybrid%20GC%202%20Channel/Hybrid02-08.jpg)
(http://img23.photobucket.com/albums/v70/jojod818/Tube%20Hybrid%20GC%202%20Channel/Hybrid02-06.jpg)
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FASTBACK,
Galing LM12 mo ah! It would have been nicer if you have designed a pcb that holds the TO-3 opamp for a more shorter path especially for the supplies which causes spurous oscillations. Yan kasi nabasa ko sa National Semi about that chip. Pero kung ok naman then ayus!
Sidenote: 2:10AM na di pa din ako makatulog, sarap kasi pakinggan ng hybrid...
JojoD
JojoD
It was really my first thought to make a PCB to Solder the PCB directly, and another is to do a point to point wiring. Kaso na atat ako gumawa kaya ayun connect na lang siya ng wires. But so far I wala pa naman siya problema, hindi ko pa siya pinapatay since yesterday. Tested it sa different types of music from Bass, Disco, Love songs and Jazz Vocals.
I think I have to redesign the circuit to accomodate the tube preamp, kailangan ng High Zin to match it. Maghahagilap na naman ako ng libro ko na basic electronics for the computation hehehe.
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Good luck!
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stereo hybrid gainclone... thanks jojoD!
(http://203.131.66.146:8080/gc3.jpg)
minimalist solid state... one channel.
(http://203.131.66.146:8080/gc1.jpg)
tube buffer section with single 6922 tube.
(http://203.131.66.146:8080/gc2.jpg)
sounds great! very detailed and has good bass weight.
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Akyat,
Yan na ba yung Hybrid GC mo?
JojoD,
Pa PM naman ng price for custom jobs. ;D
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slayer,
You have PM.
akyat!
Galing camera mo dude! It's nice to know you enjoy listening to your hybrid.
Regards,
JojoD
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stereo hybrid gainclone... thanks jojoD!
minimalist solid state... one channel.
tube buffer section with single 6922 tube.
sounds great! very detailed and has good bass weight.
Since I read the LM sonic measurement (somewhere) in this thread, I have indulge myself reading the DIYaudio chipamp forum for days. Then I source an integrated clone amp and test it with my 8.3. All the reports are indeed true. My gainclone was able to shake my 8.3 more than my heavy raw-transistor gear - smooth bass slams, clear imaging, and crisp high (from a textile tweeter?).
What Jojo is doing here is really worth considerations if you are in MUSIC listening than THEATER. Though the character of the chip amp itself is already tube-like (or maybe better - no odd harmonics, no even harmonics, better bass and high, lots of power), I somehow believe that either tube or SS in the buffer section will both give good performance, having this good chip amp in the driver stage (as attested by the DIYaudio chip amp forum). I am now using an integrated gainclone on my 8.3 - rubber-like bass, clear mid-range imaging, and crisp high.
I should have known this earlier, and could have saved a lot, and have enjoyed so good a music from the start!
Akyat!
Since you have a museum of amps, can you somehow describe sound of the hybrid project of Jojo compared with your other collections?
Jojo,
which circuit design did you implement (the Thorten, Daniel, Elliot, or your own) ?
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Sir Jojo,
Replied to your PM. :)
slayer,
You have PM.
akyat!
Galing camera mo dude! It's nice to know you enjoy listening to your hybrid.
Regards,
JojoD
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What Jojo is doing here is really worth considerations if you are in MUSIC listening than THEATER. Though the character of the chip amp itself is already tube-like (or maybe better - no odd harmonics, no even harmonics, better bass and high, lots of power), I somehow believe that either tube or SS in the buffer section will both give good performance, having this good chip amp in the driver stage (as attested by the DIYaudio chip amp forum). I am now using an integrated gainclone on my 8.3 - rubber-like bass, clear mid-range imaging, and crisp high.
Jojo,
which circuit design did you implement (the Thorten, Daniel, Elliot, or your own) ?
The tube hybrid monoblocks were intended for HT while the 2-channel version is for MUSIC. Indeed SS or TUBE buffers should work well, I know becasue I have both. However, in an electronics point of view, TUBE buffers have their electronic parameters well suited for GC as buffers. I'm not saying SS buffers don't sound good or don't work well, but for this application, I would use TUBES as a buffer because of it's "electronic" character. Besides, the cost of a decent laser cut opamp would be in the hundreds too.
JojoD
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Sir Jojo,
Replied to your PM. :)
Got it, thank you very much.
JojoD
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Sir JojoD818, Sent you PM. :)
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Akyat!
Since you have a museum of amps, can you somehow describe sound of the hybrid project of Jojo compared with your other collections?
i was planning to post a more exhaustive review after i've lived with the amp for a few weeks, still getting myself immersed in its sound... using it now directly hooked to my CD/DVD player... no need for a preamp, it's already loud at 9:00 on the volume pot... i think it has its own unique sound, but i will need more time to identify what makes it different.
my initial impression was that it has impressive detail from highs to lows... the bass is tight & tuneful, something that i like about my other hybrid amp, the Luxman LV-105... i haven't done a side-by-side comparison yet but from memory i would say that the gainclone has more extended bass... which is really surprising, since you won't find power supply capacitors of the size you normally find in amps that sound like this... i have at least 3 amps that have more bass quantity than the gc, but 2 of them are more suited to HT applications, i find them at times to be a little too boomy on music... the gc's bass is just right for me, neither overpowering nor boomy, and you can tell different bass notes quite easily... i had the chance to compare it briefly with tube amps (Dynaco ST70 and AMX EL34 push-pull), and i must admit that the gainclone sound very much solid state (lean & fast) next to these 2 lush tubey amps... a more similar sounding tube amp would probably be the AMX 6550SE in penthode mode.
the mids and highs are very detailed... i find it neutral, neither forward nor laid back... for comparison my Sansui is more laid back while my Onkyo Integra is more forward... i would say the mids & highs are closest to my Luxman & Accuphase amp, both of which are good calibre brands yet the gainclone can compete with them as equals, and probably can even beat them.
just my initial impressions... will update in 2-3 weeks.
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i was planning to post a more exhaustive review after i've lived with the amp for a few weeks, still getting myself immersed in its sound... using it now directly hooked to my CD/DVD player... no need for a preamp, it's already loud at 9:00 on the volume pot... i think it has its own unique sound, but i will need more time to identify what makes it different.
my initial impression was that it has impressive detail from highs to lows... the bass is tight & tuneful, something that i like about my other hybrid amp, the Luxman LV-105... i haven't done a side-by-side comparison yet but from memory i would say that the gainclone has more extended bass... which is really surprising, since you won't find power supply capacitors of the size you normally find in amps that sound like this... i have at least 3 amps that have more bass quantity than the gc, but 2 of them are more suited to HT applications, i find them at times to be a little too boomy on music... the gc's bass is just right for me, neither overpowering nor boomy, and you can tell different bass notes quite easily... i had the chance to compare it briefly with tube amps (Dynaco ST70 and AMX EL34 push-pull), and i must admit that the gainclone sound very much solid state (lean & fast) next to these 2 lush tubey amps... a more similar sounding tube amp would probably be the AMX 6550SE in penthode mode.
the mids and highs are very detailed... i find it neutral, neither forward nor laid back... for comparison my Sansui is more laid back while my Onkyo Integra is more forward... i would say the mids & highs are closest to my Luxman & Accuphase amp, both of which are good calibre brands yet the gainclone can compete with them as equals, and probably can even beat them.
just my initial impressions... will update in 2-3 weeks.
That's the gainclone I know alright. Been using mine for 3 months now. It doesn't have the lushness of tubes but the resolution and speed makes this little big amp far from boring. May I know how big your filter caps are? Do you have a DC blocking cap? I use the OPA549, 2200uf per rail and no DC blocking cap. I'm so tempted to resurrect my elliot hybrid GC which died after two days when I accidentally put in the wrong polarity for the cap filters (experimenting with different filter values). The weird things is, I thoughts its the cap that will explode if you have the polarity incorrect but in this case its the chip. I'm still using the cap for my straight gainclone and works ok.
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I use the OPA549, 2200uf per rail and no DC blocking cap. I'm so tempted to resurrect my elliot hybrid GC which died after two days when I accidentally put in the wrong polarity for the cap filters (experimenting with different filter values). The weird things is, I thoughts its the cap that will explode if you have the polarity incorrect but in this case its the chip. I'm still using the cap for my straight gainclone and works ok.
When a cap is installed in a reverse position, it will try to charge itself in reverse. Depending on it's voltage rating and the magnitude of the voltage impressed, that's what makes it explode. And that reverse charging is what killed your chipamp.
BTW, I use to blow-up capacitors just for FUN. With a very long wires of course! >:D
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Sir JojoD818, Sent you PM. :)
You have a reply. :)
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Sir Akyat. Sent you pm. :)
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peeps,
how much would it cost (estimate lang) to make a gc stereo amp? yung basic lang. used to make electronic projects in college and wanna try this one out in my spare time. is there any site you can recommend that can show step by step construction? it would be a great help ;D
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peeps,
how much would it cost (estimate lang) to make a gc stereo amp? yung basic lang. used to make electronic projects in college and wanna try this one out in my spare time. is there any site you can recommend that can show step by step construction? it would be a great help ;D
Maybe less than 1 thousand pesos, you can have the chips for free thru the Ti website. if you view the earlier post there are lots of information regarding the GC amp.
Good luck
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cousin skeeter
Also try reading this Thread at DIYaudio to long but you can get lot's of information.
http://www.diyaudio.com/forums/showthread.php?s=&threadid=9112&perpage=15&pagenumber=1
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peeps,
how much would it cost (estimate lang) to make a gc stereo amp? yung basic lang. used to make electronic projects in college and wanna try this one out in my spare time. is there any site you can recommend that can show step by step construction? it would be a great help ;D
These sites offers step by step instruction with tips.
http://www.decdun.fsnet.co.uk/gainclone.html
http://www.geocities.com/rjm003.geo/rjmaudio/diy_gc.html
But you might want to try this schematic instead of the one in the Decibel Dungeon site, which is what most diyers at chipamp DIYaudio have now settled on. You can actually omit the 4.7uf output cap and replace that with a 220r resistor, your choice. You can also choose to omit R5 and C4.
(http://www.decdun.fsnet.co.uk/gc/noninvertedGC.jpg)
Here's for the power supply.
(http://jwg.student.utwente.nl/fedde/audio/supply.gif)
The schematic above uses a trafo with dual secondaries and two bridges per secondary. If you're transformer is center tapped which is what's commonly availble locally, you only need one bridge and your center tap is your ground wire which run directly to the amp section.
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garp,
thanks bro. went through some websites and i learned a lot. i think this is a good project to restart my love for electronics. no time na talaga lately eh.
fastback,
TI website? wats the complete URL bro. might get em free chips, hehehe. and thanks!
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I very much share Akyat's impressions on his GC in terms of mids and hi's. It can equal my tube amps in these departments. :)(Caveats with the limited tube gear that I have.) And yes, GCs are not syrupy -- is that the right work for tube sweetness ????
But am surprised that Akyat's GC has tight bass -- an area which mine needs some tweaking. Hmm ???, mukhang yg 1uf yellow cap did the trick (am currently using 3.3).
Pero tampo :( ako ke Jojo kc mas pogi yg innards ng kay Akyat o baka camera lg -- btw, what camera is that, Akyat -- CRYSTAL CLEAR!
In my set HT setup of GCs, I love it best in the movie Twister :) :). Others may want to try it even at stereo mode. Hanep sa metal sound efx. (Altho' I have no real experience with twisters to serve as benchmark.)
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Akyat,
Congrats pala sa bago mong Gainclones amp.. sound was impressive, power is there and frankly amazed with its high and mid not your typical SS sound, yun tight bass ang type ko rin.. remembering my HK hehehehe
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eXg,
There is a secret component that is hidden within that 2-channel hybrid that I built for akyat. It is so hidden that no eye or camera can find it. O0 That is the difference between yours and his. ;D ;D ;D Even the resistor values below the tube is spy proof! Hahahaha.
JojoD
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fastback,
TI website? wats the complete URL bro. might get em free chips, hehehe. and thanks!
cousin skeeter
Here: http://www.ti.com/
You have to register first to be eligible for their sample program.
Hope to see your Gainclone amp soon.
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What free chip you will get when you registered?
cousin skeeter
Here: http://www.ti.com/
You have to register first to be eligible for their sample program.
Hope to see your Gainclone amp soon.
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Akyat,
Congrats pala sa bago mong Gainclones amp.. sound was impressive, power is there and frankly amazed with its high and mid not your typical SS sound, yun tight bass ang type ko rin.. remembering my HK hehehehe
sir akyat,
congrats nga pala dun sa bago mong gc amp. galing din, if only my dvd player has separate 5.1 channel outputs like philips dvd players, pwedeng pamalit sa av receiver. >:D >:D >:D
sir hans,
ok yun kung halos pareho sila ng hk, value for money.
sir jojoD,
meron bang discount kung group buy o kung 3 pagawa (seriously)? :D
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What Jojo is doing here is really worth considerations if you are in MUSIC listening than THEATER. Though the character of the chip amp itself is already tube-like (or maybe better - no odd harmonics, no even harmonics, better bass and high, lots of power),
aHobbit,
For my education, care to explain further on two points:
1. Music than Theatre - what are the criteria considered?
2. neither odd or nor even harmonics - i thought a component, even musical instruments should have either -- or both? ???
Salamat.... :)
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What's the difference between OPA549S and OPA549T? Will they have different parameters?
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Those interested in GC might be interested in a KIT here:
http://www.briangt.com/order/
For one channel
(http://www.briangt.com/gallery/albums/nigc-kit/build016.sized.jpg)
Peter Daniel also sells the accompanying case here:
http://www.specializedkits.com/integrated-amp.html
(http://www.specializedkits.com/images/int-noTop.jpg)
(http://www.specializedkits.com/images/gainclone-front-left.jpg)
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cousin skeeter
Here: http://www.ti.com/
You have to register first to be eligible for their sample program.
Hope to see your Gainclone amp soon.
actually i saw the site already yesterday, browsed through the thread and saw the site. was able to order sample chips for the 541 and the 549. hope to get them soon and get on with this project. :) :)
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actually i saw the site already yesterday, browsed through the thread and saw the site. was able to order sample chips for the 541 and the 549. hope to get them soon and get on with this project. :) :)
cousin skeeter
Nice to hear that, you will surely get that sample chips.
Good luck on your GC amp.
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anyone got paypal? I would like to try the kits O0
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Is there any limit on sample order?
actually i saw the site already yesterday, browsed through the thread and saw the site. was able to order sample chips for the 541 and the 549. hope to get them soon and get on with this project. :) :)
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you can get 10 different items and in most cases 3 pieces of each (they'll give only two pieces of expensive ones like the hermetically sealed OPA541)
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But am surprised that Akyat's GC has tight bass -- an area which mine needs some tweaking. Hmm ???, mukhang yg 1uf yellow cap did the trick (am currently using 3.3).
Pero tampo :( ako ke Jojo kc mas pogi yg innards ng kay Akyat o baka camera lg -- btw, what camera is that, Akyat -- CRYSTAL CLEAR!
i'm just using a 2megapix canon ixus v2... it's really the photoshop processing that does wonders to the pictures... i always adjust the brightness levels and sharpen the picture first before resizing & saving it for the web.
would a slightly higher value in the caps increase the bass? not that i need it, just curious what this does to amps in general... the circuit seems so simple and small it's really amazing how it sounds... i think the whole thing would fit inside the chassis of my preamp, w/c is about the size of a book... i'm having all kinds of ideas with this, not that i'd do it myself of course but its good to know i can ask somebody else to D-I-4-me.
i listened to the eagles hell freezes over last night... the low notes of the percussion at the start of hotel california is there... since my amp uses the LM3875 chip its capable of 56watts/ch continuous into 8ohms, and 100watts during dynamic peaks... how much power would you get if you bridge 2 channels into 1?
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since my amp uses the LM3875 chip its capable of 56watts/ch continuous into 8ohms, and 100watts during dynamic peaks... how much power would you get if you bridge 2 channels into 1?
Ok now, take a pen and some papers and get ready for some math. ;D But it is possible.
Bridge LM3875 = 100W
Parallel LM3875 = 100W
Bridge Parallel LM3875 = 200W
I hope your not serious. I only tried the Bridge Parallel though.
As for the sonics, my experience is that it actually depends on the chipamp used. For me, the LM3875T would be my choice. I only compared it with LM383T, LM1875, LM3886TF, LM3876, OPA541, OPA548, OPA549, TDA1514A, TDA2030A, TDA2050A, TDA7293, and TDA7294.
Now I wish I can compare the LM3875 with the LM4780 chip, oh well, that can wait. I still have a tube crossover to finish.
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I hope your not serious. I only tried the Bridge Parallel though.
nahh i'm just curious... ;D ;D ;D i saw tony building a bridge parallel gc using a pc case as his chassis... you need 4 chips per ch in that case right? 200w is a lot, i wonder if having 2 or 4 per ch would change the sound... will it just be the same but louder?
know what? it sounds like it's actually more than 56wpc... i did a side-by-side comparison with my luxman last night, sort of like a hybrid amp shootout... the luxman is rated 105wpc at 6ohms while my gc is 56wpc into 8ohms... my impression was that because the gc had deeper bass, it sounded more balanced at higher volume... anyway i haven't yet tried listening to it at very LOUD levels coz i only get to switch it on late in the evening.
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nahh i'm just curious... ;D ;D ;D i saw tony building a bridge parallel gc using a pc case as his chassis... you need 4 chips per ch in that case right? 200w is a lot, i wonder if having 2 or 4 per ch would change the sound... will it just be the same but louder?
know what? it sounds like it's actually more than 56wpc... i did a side-by-side comparison with my luxman last night, sort of like a hybrid amp shootout... the luxman is rated 105wpc at 6ohms while my gc is 56wpc into 8ohms... my impression was that because the gc had deeper bass, it sounded more balanced at higher volume... anyway i haven't yet tried listening to it at very LOUD levels coz i only get to switch it on late in the evening.
akyat,
In my experience with bridge parallel, the sonics stays the same but it really gets very loud. However, lots of care must be taken to reduce output offset or else, one of the chips may become hotter than the others. Using pc casing for amps was a college project of mine too.
JojoD
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would a slightly higher value in the caps increase the bass? not that i need it, just curious what this does to amps in general... the circuit seems so simple and small it's really amazing how it sounds... i think the whole thing would fit inside the chassis of my preamp, w/c is about the size of a book... i'm having all kinds of ideas with this, not that i'd do it myself of course but its good to know i can ask somebody else to D-I-4-me.
The experience of others at DIYaudio including mine is that the bass tends to increase and slow down a little with increasing filter caps. Peter Daniel says that large filter caps tend to compromise the top end (although I'm not sure I buy this one). That's why the preferred filter cap should be 1000uf per rail for the 25wpc GC and no more than 2,200uf per rail for a 50wpc gainclone. These are the same values in the original gaincard. The chip here is the LM3875 which has a high supply ripple rejection to begin with and this makes it possible to use small values for the filter. The speed of the GC can be attributed to this.
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Ok now, take a pen and some papers and get ready for some math. ;D But it is possible.
Bridge LM3875 = 100W
Parallel LM3875 = 100W
Bridge Parallel LM3875 = 200W
I hope your not serious. I only tried the Bridge Parallel though.
As for the sonics, my experience is that it actually depends on the chipamp used. For me, the LM3875T would be my choice. I only compared it with LM383T, LM1875, LM3886TF, LM3876, OPA541, OPA548, OPA549, TDA1514A, TDA2030A, TDA2050A, TDA7293, and TDA7294.
Now I wish I can compare the LM3875 with the LM4780 chip, oh well, that can wait. I still have a tube crossover to finish.
JojoD, I'd be very interest to know what your findings will be on LM4780. Looks like one powerful chip. I'd be happy if it sounds like the 3875 but with more power ;D
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OT. just found out i can track the shipment TI made with UPS concerming my OPA chips on the UPS site. currently my package is in alaska. kinda wondering why it has to pass through alaska to get here. hmmm
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OT. just found out i can track the shipment TI made with UPS concerming my OPA chips on the UPS site. currently my package is in alaska. kinda wondering why it has to pass through alaska to get here. hmmm
Baka i-frozen yun chips para maganda tunog like cryoed tubes. ;D ;D ;D Joke Joke Joke
The important thing is it's on it's way dba?
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JojoD, I'd be very interest to know what your findings will be on LM4780. Looks like one powerful chip. I'd be happy if it sounds like the 3875 but with more power ;D
I'll inform you my findings when I get the chance to try one. :)
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aHobbit,
For my education, care to explain further on two points:
1. Music than Theatre - what are the criteria considered?
2. neither odd or nor even harmonics - i thought a component, even musical instruments should have either -- or both? ???
Salamat.... :)
eXg,
not familiar to your sound inclination and from what view you are coming from. anyway, here is my reply to your querry.
(1) the statement is not a comparison of HT gear or music gear, but is intended to a persons inclination: can be rephrased as this: If you are more into music than theater. . .
(2) I would say, I thought too. I have no measuring tool, and have not into tube. But I have complaints with usual (maybe hyped) transistor sound. After reading the post of GARP (Reply #485 on: Mar 16, 2004 at 12:05 PM) on this thread, I read the site specified
"Why Gainclones Work"
http://www.adx.co.nz/techinfo/audio/gainclone1.htm
The measurement shown there made me discover a lot of things (provided, the person is honest enough - but from his discussion, he seems not also a transistor lover nor a GC lover, but out of curiosity, gave it a try, and explained why GC is in fact, a different breed of its own). Remembering audiophile rejecting GC in the past, their statement of complaint does not made reference to sound character, but on the fast turn-over of GC model in the market, which make GC amp difficult to maintain overtime (unlike with tube and transistor based amps). I also rejected GC concept prior to reading the site garp posted.
Looking at the graph of harmonics, you will note that the output of 2nd and up harmonics are down by about -70dB on both 8 and 4 ohm load and about -100dB for 3rd harmonics. This means, this GC amp produces no harmonic artifacts (as contrasted by transistor for odd harmonics and the tube for even harmonics).
He further explained, and this is my words of understanding on the discussion: the PP wiring of tubes and minimal components made it to sound good, but the character is somewhat on the mid. But somehow deficient on high/low freq and power output.
The GC is not a minimalist design (in reality). It has lots of transistor inside, but is so wired closely, that impedances connecting these transistors are almost gone, further, its vulnerability to pik up unwanted signals has been substantially down. providing a well-selected support (external) component to the chip, and wired it to the chip as close as possible, will extend the internal design of the GC, resulting in an almost same performance as tube (harmonics wise) but has more power, bandwidth extension and speed.
This gave credence to the comment of ramble_on earlier also in the thread, that this could be the middle ground between tube and transistor, easy to construct, cheap, and has more power and extensions. However, the National Semicon engineers had been so good in the design (if the site above is to be believed) that both harmonics (odd and even) are both out.
I salute Joan2 on this subject raised on the forum. I interpreted the whole discussion that all gainclone maybe having the same performance. After reading some other forums and checking datasheet of various GC, the following can be said: get the right spec GC, and basically GC will sound as presented in the site, because of wiring proximity. The selection of GC, whether TDA or OPA or LM will now become just a matter of individual taste or preferences or construction difficulty.
JojoD818 made his projects, and if you want a care free construction, he can do it for you, and you will have a third option on your quest of sound reproduction. As for me, I have also found a cheaper and faster way to this.
After all my research, I venture to try some GC amps (about 6 different makers) that I can take hold. I am surprised to have them sound on my wharf 8.3. Lately, I was able to source a 2x 80Watts integrated GC. I just cant believed I overlooked them in the past, only to find out they are the one giving out the best, if designed properly, sound body more listenable than my transistor amps even at high levels. Also noted that crown International (a subsidiary of HK) also made pro amps bsed on GC. Some noted high end which won raved accepatance among critical audiophiles used GC. My 8.3 diamond does not need a subwoofer anymore, at direct (tone bypass) flat setting.
For me, GC gave me the best of sonics (with Wharf 8.3 - which seems to be always thin sounding on most transistors - but a revelation with GC). The best things in life are not necessarily expensive on this internet age.
It's just me though.
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The experience of others at DIYaudio including mine is that the bass tends to increase and slow down a little with increasing filter caps. Peter Daniel says that large filter caps tend to compromise the top end (although I'm not sure I buy this one). That's why the preferred filter cap should be 1000uf per rail for the 25wpc GC and no more than 2,200uf per rail for a 50wpc gainclone. These are the same values in the original gaincard. The chip here is the LM3875 which has a high supply ripple rejection to begin with and this makes it possible to use small values for the filter. The speed of the GC can be attributed to this.
I might believe PD findings. If you are to look the caps as DC storage to aid power delivery to GC, you might say higher caps, but seems to be not working with GC per PD findings. To me this looks that the caps there is not for power storage anymore (which is why they recommended a higher capacity trafo to resolve power regulation and power storage capacity), but the caps is more to arrest unwanted freq entering the GC (perhaps the lower nuisance freq since the other lower cap in parallel to these electrolytic caps have been left out by PD - provided the distance between your supply and GC is made to a minimum)
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After all my research, I venture to try some GC amps (about 6 different makers) that I can take hold. I am surprised to have them sound on my wharf 8.3. Lately, I was able to source a 2x 80Watts integrated GC. I just cant believed I overlooked them in the past, only to find out they are the one giving out the best, if designed properly, sound body more listenable than my transistor amps even at high levels. Also noted that crown International (a subsidiary of HK) also made pro amps bsed on GC. Some noted high end which won raved accepatance among critical audiophiles used GC. My 8.3 diamond does not need a subwoofer anymore, at direct (tone bypass) flat setting.
For me, GC gave me the best of sonics (with Wharf 8.3 - which seems to be always thin sounding on most transistors - but a revelation with GC). The best things in life are not necessarily expensive on this internet age.
It's just me though.
Could this 80W GC you're reffering to be an SGS Thomson DMOS? Or probably a Sanyo STK Thick Film hybrid? Well, whatever it is, congrats on your success.
I completely agree with you on the matter of gc. Solid state can surely sound good when properly designed. Now as for tubes, I have always been curious about them when I was a kid but didn't paid any attention, especially when I was in college when the prof, is talking about load lines. Duh, I only paid attention when he talked about transistors, opamps, logic circuits. I never thought that I would be doing projects with tubes. Now I know why engineers respect the past, for the present won't have a future without the past.
Cheers!
JojoD
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got my opa549s chips from TI! still waiting for the 541s though. cant wait to work on em this weekend :)
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bakit napunta ito sa thread ng Speakers? Looks like better fit sa Amps section. Mod?
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Does resistor's power rating matter? What if i use say 2Watt resistor on a circuit which can handle 1/2 or 1Watt resistor?
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updating my OPA549 bridge-parallel subwoofer
(http://groups.msn.com/_Secure/0SADtAjcVMgVfz5kYscXczu9gV61DmPMQItGJoscVegSPevJLLr52ioJMevXqlPoGrOC7o2guozDlGvEmU05vSy4dUWF8hhzas!42AeMLgVczAAAArXIlAg/front%20view.JPG?dc=4675468986817162139)
this will be installed at the back of the sub enclosure.
(http://groups.msn.com/_Secure/0RQAJA7EUp9vyqniQfWqLMexOTcfHPdegaAvcr9xprsbnI*iCle6aeqF*3Hm5n62DAdjHh5kILveijU6eBZZEpl3tDWc7UPjJLWnA3O9zjj4/partsview.JPG?dc=4675468986949564845)
low pass filter circuit and its power supply, along with the power amps are mounted on a single heatsink.
(http://groups.msn.com/_Secure/0RADVAiwUvLgfMO8FpXtNf4fIs1v*yuwIzZdgxvHZlgJkPbHbrKCLTEwPw0R469s2YfNWI*zquzuGzUy!6Nymt2VjQztVXOdIojMlyO33xrM/sideview.JPG?dc=4675468987137943702)
phase switch, input RCA, gain and volume pots underneath the low pass filter board.
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rmpmla,
Ikaw talaga ang tamad mo gumawa ng pcb! :P
Ayus yan! Kaso nun ganyan ginawa ko ang daming rattles. Make sure you glue all those wires and caps and whatever.
TIP: I used a 1/8" thich aluminum sheet para "plate amp" look ang dating. Keep them coming!
Mods? Amps po topics dito sirs.. Thanks!
JojoD
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Does resistor's power rating matter? What if i use say 2Watt resistor on a circuit which can handle 1/2 or 1Watt resistor?
It won't matter if you will use a higher wattage resistor in place of a lower one. However, pcb real estate and economics are the main reasons why you should use small resistors.
Cheers! Kaso gusto ko Sarsi!
JojoD
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rmpmla,
Ikaw talaga ang tamad mo gumawa ng pcb! :P
Ayus yan! Kaso nun ganyan ginawa ko ang daming rattles. Make sure you glue all those wires and caps and whatever.
TIP: I used a 1/8" thich aluminum sheet para "plate amp" look ang dating. Keep them coming!
JojoD
;D hanggang ngayon hindi ko pa nagamit yung ferric chloride at blank pcb na binili ko. tinatamad akong umpisahan lalo na pag may available na pre-etched na PCB.
Was thinking of using thick aluminum plate similar to my old M&K sub. kaya lang hirap humanap nung plate. so i end up using a heat sink :)
thanks for the tip. will glue those caps and wires
hope to post the finished sub soon
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7Even,
sent you a PM :)
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rmpmla,
many thanks....
7Even,
sent you a PM :)
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JojoD,
Many thanks.... BTW, you're pcb looks professional. How did you do that?
It won't matter if you will use a higher wattage resistor in place of a lower one. However, pcb real estate and economics are the main reasons why you should use small resistors.
Cheers! Kaso gusto ko Sarsi!
JojoD
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JojoD,
Many thanks.... BTW, you're pcb looks professional. How did you do that?
Which one? ??? ;D
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updating my OPA549 bridge-parallel subwoofer
(http://groups.msn.com/_Secure/0SADtAjcVMgVfz5kYscXczu9gV61DmPMQItGJoscVegSPevJLLr52ioJMevXqlPoGrOC7o2guozDlGvEmU05vSy4dUWF8hhzas!42AeMLgVczAAAArXIlAg/front%20view.JPG?dc=4675468986817162139)
this will be installed at the back of the sub enclosure.
(http://groups.msn.com/_Secure/0RQAJA7EUp9vyqniQfWqLMexOTcfHPdegaAvcr9xprsbnI*iCle6aeqF*3Hm5n62DAdjHh5kILveijU6eBZZEpl3tDWc7UPjJLWnA3O9zjj4/partsview.JPG?dc=4675468986949564845)
low pass filter circuit and its power supply, along with the power amps are mounted on a single heatsink.
(http://groups.msn.com/_Secure/0RADVAiwUvLgfMO8FpXtNf4fIs1v*yuwIzZdgxvHZlgJkPbHbrKCLTEwPw0R469s2YfNWI*zquzuGzUy!6Nymt2VjQztVXOdIojMlyO33xrM/sideview.JPG?dc=4675468987137943702)
phase switch, input RCA, gain and volume pots underneath the low pass filter board.
rmpmla
Alright, Here goes another amp that will rock the house.
Nice work there.
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rmpmla
Alright, Here goes another amp that will rock the house.
Nice work there.
FASTBACK,
thanks :) BTW, how's your para-bridge GC Sub doin? outboard ba siya o built-in sa sub enclosure?
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Oops sorry! :-\ The GC i mean! ;D
Which one? ??? ;D
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Oops sorry! :-\ The GC i mean! ;D
Sus! You can do that yourself! Mahirap lang yun pag design lalu na pag consider mo yun grounding, stray capacitance and so so. Pero kung jologs naman, pwede na as a start, then fine tune. ;)
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sir jojoD, pwede ba lagyan ng switch yung gc ko para gawin bridged mono? i think i might need the flexibility to use our hybrid gc as dual purpose amp: as a stereo music amp and as a mono center channel amp for my HT (together with the 6-ch passive volume pot i asked about in the other thread). ;)
i agree, this thread should be in the amplifiers section.
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sir jojoD, pwede ba lagyan ng switch yung gc ko para gawin bridged mono? i think i might need the flexibility to use our hybrid gc as dual purpose amp: as a stereo music amp and as a mono center channel amp for my HT (together with the 6-ch passive volume pot i asked about in the other thread). ;)
i agree, this thread should be in the amplifiers section.
Oh sure ulit! Pwede yun in theory pero not tried it in actual. Just need to invert the other channel para opposite yun signal phase sa input then use both + speaker out. However, you will end up using only an 8 ohm speaker since each amp will see half.
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FASTBACK,
thanks :) BTW, how's your para-bridge GC Sub doin? outboard ba siya o built-in sa sub enclosure?
rmpmla
Naghihintay pa rin po ng enclosure and the low pass filter. I plan to use it as an outboard amp.
Sir pareho tayo I haven't touched the copper clad and the ferric chloride since I bought it. nakakatamad kasi mag design.
Anyway Sir try mo experiment na disconnect yung sense pins of the DRV134.
Thanks
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tinatamad akong umpisahan lalo na pag may available na pre-etched na PCB.
sir, saan ka nakakabili ng pre-etched PCB? thanks for the help
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sir, saan ka nakakabili ng pre-etched PCB? thanks for the help
You can buy them from any electronic shop. They are normally known breadboarding pcb's and labeld as PC-101, PC-201, PC301.
HTH,
JojoD
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tks Jojo. can you tell me the specififc store. been to deeco everywhere, cant find any!
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tks Jojo. can you tell me the specififc store. been to deeco everywhere, cant find any!
Ang alam ko meron sa Deeco. CMC, a local firm makes them.
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aHobbit
Sa alexan meron sila. I use a PC-401 and cut it into 4pcs para sa GC.
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mga bro,
sensya na ha, hindi ako lagalag eh. saan po store ng alexan? daming salamat po!
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mga bro,
sensya na ha, hindi ako lagalag eh. saan po store ng alexan? daming salamat po!
If your in Raon, sa Sales St., almost besides Deeco, lapit sa Philippine College of Criminology (dami dun cops ;D).
Kung nasa SM City North EDSA ka naman, sa Carpark meron silang branch, Sa Megamall din sa 5th floor, not sure lang kung Bldg A or B ;D
Ultimately, kung sobrang hassle humanap eh di p2p wiring mo na lang!
HTH
JojoD
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Ultimately, kung sobrang hassle humanap eh di p2p wiring mo na lang!
HTH
JojoD
I totally agree poit to point wiring mo na lang, di ka pa mahihirapan pag install ng PCB sa casing.
JojoD
What is your latest project?
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I totally agree poit to point wiring mo na lang, di ka pa mahihirapan pag install ng PCB sa casing.
JojoD
What is your latest project?
Actually I have 2 upcoming projects. A para-bridge down-firing sub with all the amenities of a hi-end one (I hope it sounds hi-end, it's not mine ;D), and a ss phono preamp. My souped up hybrid will have to wait another month. I am still practicing some soldering technique passed to me by a former US Marines.
How about you? How's your projects doing?
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Actually I have 2 upcoming projects. A para-bridge down-firing sub with all the amenities of a hi-end one (I hope it sounds hi-end, it's not mine ;D), and a ss phono preamp. My souped up hybrid will have to wait another month. I am still practicing some soldering technique passed to me by a former US Marines.
How about you? How's your projects doing?
1. Tube preamp, I still have to buy the capacitors. I wasn't able fo find enough caps on our dead TV.
2. Solid state preamp, Designing the PCB.
3. Subwoofer LPF, Also designing the PCB.
Finally I will be able to use the copper clad and the ferric chloride I bought. The GC amps I built are still waiting for a chassis, same here they can wait.
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1. Tube preamp, I still have to buy the capacitors. I wasn't able fo find enough caps on our dead TV.
2. Solid state preamp, Designing the PCB.
3. Subwoofer LPF, Also designing the PCB.
Finally I will be able to use the copper clad and the ferric chloride I bought. The GC amps I built are still waiting for a chassis, same here they can wait.
Imagine a p2p 24db LPF? Impossible!
Good luck on your PCBs!
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Imagine a p2p 24db LPF? Impossible!
Good luck on your PCBs!
Hehehe you'll go crazy doing p2p.
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Hehehe you'll go crazy doing p2p.
Crazy indeed, but imagine what it would look like. It would inspire a new cult in soldering! Hahahah
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Finally I have finished designing the PCB layout for my project's, at first it was really tough since the last time I made one was six years ago while I was doing my design in college, but after awhile I got used to it and made four design.
JojoD what software are you using for PCB design?
I just used a niche software PCB design.
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Finally I have finished designing the PCB layout for my project's, at first it was really tough since the last time I made one was six years ago while I was doing my design in college, but after awhile I got used to it and made four design.
JojoD what software are you using for PCB design?
I just used a niche software PCB design.
Before, MS Paint. Now CorelDraw.
I have tried those OrCAD and Protel suites but I can't work it out. It just drives me crazy so my advise is use which is easier for you.
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jojoD
Sent U an email.
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jojoD
Sent U an email.
Got your email, thanks!
Will try this one soon.
JojoD
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Got your email, thanks!
Will try this one soon.
JojoD
Hope you like it, I find it easy to use in designing a PCB.
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Hope you like it, I find it easy to use in designing a PCB.
I find Corel to be easy as time goes by. But this one surely deserves a try. Looks very easy to use, though I still need to learn things especially the printing since I sometimes send pcb data on paper.
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boss jojo, san kayo nagpapagawa ng pcb?
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boss jojo, san kayo nagpapagawa ng pcb?
Hehehe, I own the "pagawaan ng pcb".
Pleeeezzz drop the boss, the sir, the master.
Just Jojo would be great my friends!
;D
JojoD
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hi jojo, sent u pm.
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I find Corel to be easy as time goes by. But this one surely deserves a try. Looks very easy to use, though I still need to learn things especially the printing since I sometimes send pcb data on paper.
In that software no problem in printing, it has alot of options. One thing I noticed though is that there is no parts placement only designing the foils side.
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hi jojo, sent u pm.
You have a reply...
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In that software no problem in printing, it has alot of options. One thing I noticed though is that there is no parts placement only designing the foils side.
I tried it! It is really fun! However I find it useful for only small quantities of parts. I tried to do a lpf with the program and got lost with the parts. ;D Anyway, thanks again!
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my interest in building my gainclone has again resurfaced ;D
I already have the parts except for the power supply... having very little knowledge in electronics, I still can't figure out how the power supply fit into the gainclone schematic... could I just connet the output of the transformer to the GC circuit? or do I need another circuit to convert it from AC to DC?
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my interest in building my gainclone has again resurfaced ;D
I already have the parts except for the power supply... having very little knowledge in electronics, I still can't figure out how the power supply fit into the gainclone schematic... could I just connet the output of the transformer to the GC circuit? or do I need another circuit to convert it from AC to DC?
Assuming you have the filter caps close to your gainclone, you only have to rectify the ac from your trafo and connect it directly to the gc pins.
Again, the sequence is, trafo - bridge retifier - filter caps - gainclone. be careful with the trafo wiring, it involves AC mains wiring so safety first. Suggest you have another person with you to verify the wiring whenever possible.
Good luck,
JojoD
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Assuming you have the filter caps close to your gainclone, you only have to rectify the ac from your trafo and connect it directly to the gc pins.
Again, the sequence is, trafo - bridge retifier - filter caps - gainclone. be careful with the trafo wiring, it involves AC mains wiring so safety first. Suggest you have another person with you to verify the wiring whenever possible.
Good luck,
JojoD
JojoD,
This is kinda OT but can you refer me/us to books on amps and preamps design that are available sa pinas? thanks!
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I assume that the filter caps are the capacitors already in the GC Circuit...
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I assume that the filter caps are the capacitors already in the GC Circuit...
Yes! That's right. To help you better, can you please tell which chip it is, what's your config. NIGC or IGC.
Move!
JojoD
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JojoD,
This is kinda OT but can you refer me/us to books on amps and preamps design that are available sa pinas? thanks!
If you are interested in electronic principles and theories, then McGraw-Hill publications has several books available. Check out good old National Bookstore.
However, if you are only after the practical side of electronics, Electronics Enthusiasts from Alexan Commercial is your best bet. It's very cheap, with lot's of projects to test what you have learned. Most especially, it has lot's of theories behind it. I used to have a girl who always buy me those magazines. ::) I wonder where she is >:D
JojoD
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Yes! That's right. To help you better, can you please tell which chip it is, what's your config. NIGC or IGC.
Move!
JojoD
I have the ever popular OPA549... as for the inverting or non-inverting I have no idea... how can I tell?
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I have the ever popular OPA549... as for the inverting or non-inverting I have no idea... how can I tell?
If you apply the input signal to the + input pin then it is NIGC. If signal is applied to - input pin then it is IGC. Anyway, if you follow the circuit in the datasheet, then it is NIGC.
For the 549, a trafo with a 18-0-18 secondary will do, when rectified it will be close to +/-25V so your still inside the max +/-30V supply limit.
Godspeed,
JojoD
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If you apply the input signal to the + input pin then it is NIGC. If signal is applied to - input pin then it is IGC. Anyway, if you follow the circuit in the datasheet, then it is NIGC.
For the 549, a trafo with a 18-0-18 secondary will do, when rectified it will be close to +/-25V so your still inside the max +/-30V supply limit.
okay, bear with me on this one... I checked the diagram in the application information of the downloadable pdf file in ti.com for the OPA549 and I can't seem to make out what ZL stands for.
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okay, bear with me on this one... I checked the diagram in the application information of the downloadable pdf file in ti.com for the OPA549 and I can't seem to make out what ZL stands for.
ZL is the load impedance (your speakers... 4 ohms, 8 ohms, etc.)
Use 1K ohms for R1 and 22K ohms for R2. Warning, others may disagree with this, but those values will work, just change them later to your desired gain. Donot put any connection to pin #9, you can discover it's use later when your GC sings.
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ZL is the load impedance (your speakers... 4 ohms, 8 ohms, etc.)
Use 1K ohms for R1 and 22K ohms for R2. Warning, others may disagree with this, but those values will work, just change them later to your desired gain. Donot put any connection to pin #9, you can discover it's use later when your GC sings.
if ZL is the speaker what do I connect to the VO? I'll try the values you specified
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if ZL is the speaker what do I connect to the VO? I'll try the values you specified
Vo this is where you connect your speaker.
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if ZL is the speaker what do I connect to the VO? I'll try the values you specified
Stupid me, too quick on the trigger. ZL is a Boucherot cell (Zobel network) made up of a resistor and a capacitor in series. Common values are 10 Ohms/2W and 0.1uf/100V.
This cell is installed as a safeguard for any capacitive loads such as a Kimber speaker cable. VO is your output. This is where you connect your speaker's + leads and the - leads go directly to your star ground.
You can omit the Zobel network if you won't be using any special (sometimes DIY) speaker cables. It won't hurt if you use it though.
JojoD
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getafix,
I forgot to mention that my webpage has a project that uses the OPA549. Go here: http://www.geocities.com/jojod818/index.html
PCBs and schematics that you refer to are also there. If you don't know how to make a PCB, then point-to-point wiring is a good alternative.
Sarsi!
JojoD
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Go here: http://www.geocities.com/jojod818/index.html
PCBs and schematics that you refer to are also there. If you don't know how to make a PCB, then point-to-point wiring is a good alternative.
last questions... at least for the moment ;) , do you have a schematic of your power supply?
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last questions... at least for the moment ;) , do you have a schematic of your power supply?
You can use this schematic for your PSU. Read the 549 datasheet for the VA rating of the trafo. You can omit the caps if you already have filter caps near the chips. Otherwise, leave them be. Caps can be any electrolytic filter caps of any value since GCs have high PSRR. Remember that electrolytics are polarized parts that explode when installed improperly.
HTH,
JojoD
(http://img23.photobucket.com/albums/v70/jojod818/Dump/Simple_GC_PSU.jpg)
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jojo,
bro, i was able to receive the opa549 chips (5 pcs) from TI and was wondering if i could use them to make a bass guitar amp. ive a bass guitar i used in my college days and an old 15" daichi speaker. the amp i used to use got busted years ago. anyway, can i use the opa549s for this? bridge-parallel maybe like what you did? i want to make a 150 - 200 watt amp. the speaker is rated at 150watts nominal.
TIA!
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You can use this schematic for your PSU. Read the 549 datasheet for the VA rating of the trafo. You can omit the caps if you already have filter caps near the chips. Otherwise, leave them be. Caps can be any electrolytic filter caps of any value since GCs have high PSRR. Remember that electrolytics are polarized parts that explode when installed improperly.
HTH,
JojoD
(http://img23.photobucket.com/albums/v70/jojod818/Dump/Simple_GC_PSU.jpg)
any schematic for the bridge rectifier itself? :D my knowledge in electronics stops in following schematics
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jojo,
bro, i was able to receive the opa549 chips (5 pcs) from TI and was wondering if i could use them to make a bass guitar amp. ive a bass guitar i used in my college days and an old 15" daichi speaker. the amp i used to use got busted years ago. anyway, can i use the opa549s for this? bridge-parallel maybe like what you did? i want to make a 150 - 200 watt amp. the speaker is rated at 150watts nominal.
TIA!
Of course you can. It would be better if you still have your old chassis. Bridge parallel configuration with a compressor/limiter circuit and your ready for some serious jammin.
JojoD
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jojo,
I saw this schematic on the web:
(http://sub.allaboutcircuits.com/images/05185.png)
is this the general schematic for a the bridge rectifier that you mentioned? It also mentions that the diodes used are "1N4001 rectifying diodes" could I use that to for my GC project?
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Use 6Amp/100V rating of rectifier dioide for your GC.... ;) ;) ;)
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okay... thanks :)
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Use 6Amp/100V rating of rectifier dioide for your GC.... ;) ;) ;)
DONOT use 1N400X or 1N540X series diodes. My GC destroyed 1N5404 (3 amp rating)diodes twice. You can buy a bridge diode in a single package. Only 4 pins to connect, 2 are for AC and + and - terminals.
Since you are now into building electronics stuff, may I suggest that you also read/study basic electronics. Books are a very big help. Believe me, your GC project will be a start of so many projects to come. Preamps, tone controls, Low pass filters, high pass filters, regulated power supplies, are among the things that you would probably be building.
Good luck,
JojoD
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JojoD,
While i'm still waiting for my trafo for my tube preamp project, i built the GC amp (OPA548) using point-to-point wiring. It is now up and singing and planning to use PCB to organize wirings, do you have PCB layout for this? BTW, i also had pending sample order with TI for OPA549, can i use your layout on your website?
Regards.... :) :) :)
Andy
DONOT use 1N400X or 1N540X series diodes. My GC destroyed 1N5404 (3 amp rating)diodes twice. You can buy a bridge diode in a single package. Only 4 pins to connect, 2 are for AC and + and - terminals.
Since you are now into building electronics stuff, may I suggest that you also read/study basic electronics. Books are a very big help. Believe me, your GC project will be a start of so many projects to come. Preamps, tone controls, Low pass filters, high pass filters, regulated power supplies, are among the things that you would probably be building.
Good luck,
JojoD
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DONOT use 1N400X or 1N540X series diodes. My GC destroyed 1N5404 (3 amp rating)diodes twice. You can buy a bridge diode in a single package. Only 4 pins to connect, 2 are for AC and + and - terminals.
hmm... interesting, any idea where I may be able to purchase these? what's the rating do I need? 6A/100V rating?
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getafix,
IN400X & IN540X series diodes are 1Amp & 3Amp respectively. You can get 6A/100V rectifier diode at Deeco....
hmm... interesting, any idea where I may be able to purchase these? what's the rating do I need? 6A/100V rating?
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hmm... interesting, any idea where I may be able to purchase these? what's the rating do I need? 6A/100V rating?
Get those from Deeco. A higher rating would be better.
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jojo
from your PS schematic... I'd be using 2 Transformer for a stereo amp, right?
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JojoD,
While i'm still waiting for my trafo for my tube preamp project, i built the GC amp (OPA548) using point-to-point wiring. It is now up and singing and planning to use PCB to organize wirings, do you have PCB layout for this? BTW, i also had pending sample order with TI for OPA549, can i use your layout on your website?
Regards.... :) :) :)
Andy
I do have a PCB design for the 548, but it's not available in my website for the time being. I made so many mods that I have to mod the PCB design itself.
Regarding the 549 PCB in my website, your welcome to use it for your projects.
JojoD
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Thanks.... Is the PCB layout on your website is the actual size? If not, what size is it?
I do have a PCB design for the 548, but it's not available in my website for the time being. I made so many mods that I have to mod the PCB design itself.
Regarding the 549 PCB in my website, your welcome to use it for your projects.
JojoD
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Thanks.... Is the PCB layout on your website is the actual size? If not, what size is it?
2" X 1.5"
O0
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jojo,
would it be possible for me to purchase the pcb for the OPA549 GC?
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Thanks....
2" X 1.5"
O0
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jojo,
would it be possible for me to purchase the pcb for the OPA549 GC?
Sent you PM.
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Thanks....
Your welcome. :)
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O.T.
just bought me vol 1 and 2 of electronic enthusiasts compiled projects and circuits. i used to have them but lost them through the years. just browsed through vol 1 and the first part is a walk through on proper diy work and practical stuff (soldering, pcb lay-out, etc). a must read for anyone starting on the hobby (or re-starting like me). by the way, one volume costs P175 here in iloilo. it might be cheaper in manila. i plan to get me all 5 volumes. it has everything from mosquito-repellants to preamps to 100 watt rms/channel amps. ;D ;D ;D
thanks pala to jojo for reminding me of the magazines existence. ur a big help bro!
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thanks for the help guys... I'll try to update you on my progress on this thread.
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O.T.
just bought me vol 1 and 2 of electronic enthusiasts compiled projects and circuits. i used to have them but lost them through the years. just browsed through vol 1 and the first part is a walk through on proper diy work and practical stuff (soldering, pcb lay-out, etc). a must read for anyone starting on the hobby (or re-starting like me). by the way, one volume costs P175 here in iloilo. it might be cheaper in manila. i plan to get me all 5 volumes. it has everything from mosquito-repellants to preamps to 100 watt rms/channel amps. ;D ;D ;D
thanks pala to jojo for reminding me of the magazines existence. ur a big help bro!
Happy to help bro!
JojoD
PS, I built 2 of the EE Incredible Amp 100W amp. Medyo maselan lng pero good amp.
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thanks for the help guys... I'll try to update you on my progress on this thread.
/JojoD waiting... ;D
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Happy to help bro!
JojoD
PS, I built 2 of the EE Incredible Amp 100W amp. Medyo maselan lng pero good amp.
jojo,
one question bro. the the amp you made using the opa549 chips, how much is the power output per chip? and would it be ok if i used higher voltage transformers to increase power? what would be the advantages/disadvantages between supplying it with 18v and like say 35v. from the spec sheet it rated to have a max of 60v.
thanks!
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jojo,
one question bro. the the amp you made using the opa549 chips, how much is the power output per chip? and would it be ok if i used higher voltage transformers to increase power? what would be the advantages/disadvantages between supplying it with 18v and like say 35v. from the spec sheet it rated to have a max of 60v.
thanks!
OPA549 Power output = 75W @ 8 Ohms.
That's a big NO. The 549 supply limits are +60V for a single supply, and +/-30V for dual supplies. Since we are using dual supplies, the max voltage supply would be +/-30V, hence, if we use a 18-0-18 trafo, we get approx. +/-25.4558V per rail (18*sqr root of 2). If you intend to max out on 549, then a 20-0-20 trafo is needed. I have tried this but little gain was acquired for such an effort so I did not recommend it.
WARNING:
I have tried a 22-0-22 trafo and the poor 549 blew up. I mean, BLEW UP. Only the soldered pins on the pcb and the metal tab on the heatsink remained! Magic smoke anyone?
JojoD
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oh ok. thanks for the clarification. i rummaged through my old stuff and found me a 30-0-30 trafo i thought i could use for the project. i guess ill have to get another one. 75 watts per chip? thats pretty powerful. i thought the 549 wasnt that powerful as compared to the 541. i requested samples of the 541 but they werent shipped. backordered daw. dunno what that means. anyway, thanks again!
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oh ok. thanks for the clarification. i rummaged through my old stuff and found me a 30-0-30 trafo i thought i could use for the project. i guess ill have to get another one. 75 watts per chip? thats pretty powerful. i thought the 549 wasnt that powerful as compared to the 541. i requested samples of the 541 but they werent shipped. backordered daw. dunno what that means. anyway, thanks again!
The 549 has higher current than the 541. With the same speaker impedance, they sound the same in terms of power. When using lower impedance loads, the 549 outshines the 541 specially in the distortion section.
That means naubos na stock ng TI for their samples program and waiting sila for stocks (hopefully). Pretty much like what happened to On Semi where a group of thugs orders so many samples and then sells them. Very unethical and stupid persons indeed. >:(
JojoD
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jojo,
follow up question bro. will a 250VA trafo do (75 watts x 2 x PF) if i plan to make a stereo amp using two opa549s?
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jojo,
follow up question bro. will a 250VA trafo do (75 watts x 2 x PF) if i plan to make a stereo amp using two opa549s?
That trafo spec will do very well.
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jojo,
bro, ive several questions more pala. hope you dont mind.
1. your pcb designed for the opa549 seems to have additional components not found on the schematic namely a resistor and capacitor in series and connected to ground after Vin and also at Vout parallel to ZL. Id like to know what are the values of these capacitors. you also have a 10R resistor on your pcb layout, is this 10ohms?
2. Tama ba na you replaced the 10microfarad capacitors in the original schematic to 1000microfarad in the pcb layout? whats the purpose of this?
3. If im going to connect two opa549 amps in bridge mode, ok lang ba na 8 ohm ang load ko (a 12" woofer) for my bass amp project. from what you said, if i set them up in bridge mode, each amp will see a 4-ohm load.is this advisable? or maybe i could get a lower voltage trafo, say 15-0-15 so that the amps wont be overloaded.
4. maybe you can post the pcb layout of the bridge adapter you got from rod elliots site on your site as well.
5. will a microphone input with tone controls do as my preamp for my bass amp? used to plug my bass guitar in the mic in of our PA system and it seemed to work ok.
6. EE mag is featuring a compressor/sustainer project in one of the volumes. is this the compressor circuit you wer talking about?
hope hindi ka na kukulitan sakin bro. i just want to make sure i got everything right. am preparing the pcbs already and hopefully might get it working in a week or two.
thanks in advance!
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jojo,
bro, ive several questions more pala. hope you dont mind.
1. your pcb designed for the opa549 seems to have additional components not found on the schematic namely a resistor and capacitor in series and connected to ground after Vin and also at Vout parallel to ZL. Id like to know what are the values of these capacitors. you also have a 10R resistor on your pcb layout, is this 10ohms?
2. Tama ba na you replaced the 10microfarad capacitors in the original schematic to 1000microfarad in the pcb layout? whats the purpose of this?
3. If im going to connect two opa549 amps in bridge mode, ok lang ba na 8 ohm ang load ko (a 12" woofer) for my bass amp project. from what you said, if i set them up in bridge mode, each amp will see a 4-ohm load.is this advisable? or maybe i could get a lower voltage trafo, say 15-0-15 so that the amps wont be overloaded.
4. maybe you can post the pcb layout of the bridge adapter you got from rod elliots site on your site as well.
5. will a microphone input with tone controls do as my preamp for my bass amp? used to plug my bass guitar in the mic in of our PA system and it seemed to work ok.
6. EE mag is featuring a compressor/sustainer project in one of the volumes. is this the compressor circuit you wer talking about?
hope hindi ka na kukulitan sakin bro. i just want to make sure i got everything right. am preparing the pcbs already and hopefully might get it working in a week or two.
thanks in advance!
1. The 22K sets the input impedance and the cap in the input is a coupling cap. You can remove this if you want. The 10R and the cap in the output is a zobel network, the cap value is 0.1uf. Yes, 10R is equal to 10 ohms. Again, you can remove this if you won't use any capacitive loads.
2. That's a 1000uf cap indeed. Used for DC filtering.
3. It will work, but will have more heat dissipation, hence, you'll need bigger heatsink. Lowering the trafos voltage won't matter, it's the current that works here not the voltage. If you lower the trafo VA rating, your PSU will collapse.
4. What your asking me is extremely unethical. Rod and I have exchanged ideas before, I don't want a friend to get mad at me. ;) BTW, he makes a living by selling pcb for projects.
5. What's inside your PA system is in fact a mic preamp. I don't see any reason why it wouldn't work. Trust me, it will (that's what we use in church).
6. No, that is not the circuit I am talking about. Sorry, I haven't tried that circuit.
7. Sus!, wala na palang #7 ;D
Wag ka mag-alala, ganyan din ako nun, makulit at tanong ng tanong. Besides, I was taught once that sharing knowledge is a good deed.
Vote,
JojoD
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jojo,
thanks bro!!! i think am ready to proceed with the project. ;D ;D ;D sorry for the late reply kasi was busy poll watching. by the way, whats the value of the coupling cap you used?
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jojo,
thanks bro!!! i think am ready to proceed with the project. ;D ;D ;D sorry for the late reply kasi was busy poll watching. by the way, whats the value of the coupling cap you used?
You can use anything from 0.22uf-4.7uf whichever value you have stored in your junk box.
During elections, what was on your mind? Ballot boxes or gainclones? Hehehe
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hehehe. the ballot boxes were the priority. but now that its over with, back to the hobby na. actually i dont want to rush with the project. wana take it nice and slow. in college i used to jump in and try to do everything in one night, and i usually ended up with a not so good result, not to mention terrible workmanship. better slow but sure. sige bro, will update you with the result kung matapos ko na. thanks again!
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bro,
found the "bridging adapter for power amps" schematic on rod elliots site using tl072s and i think the layout is easy enough to understand. i also downloaded the the tl072s data sheet and i just want to be clarified with one thing. it says there that the "power supply may be taken from the preamp supply (+/- 12V to +/- 15V)". should i connect the Vcc+ pin of the chip to the +12VDC and the Vcc- pin to the -12VDC of the power supply?
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bro,
found the "bridging adapter for power amps" schematic on rod elliots site using tl072s and i think the layout is easy enough to understand. i also downloaded the the tl072s data sheet and i just want to be clarified with one thing. it says there that the "power supply may be taken from the preamp supply (+/- 12V to +/- 15V)". should i connect the Vcc+ pin of the chip to the +12VDC and the Vcc- pin to the -12VDC of the power supply?
Pinsan,
Yor understanding for the opamp pins is correct. BTW, you can use other "dual" opamps for that circuit as long as they are unity gain stable. When in doubt, just use the tl072 :P.
John... your undrilled PCBs
(http://img23.photobucket.com/albums/v70/jojod818/GC%20Dual%20Mono%20Amp/Pcb00.jpg)
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Pinsan,
Yor understanding for the opamp pins is correct. BTW, you can use other "dual" opamps for that circuit as long as they are unity gain stable. When in doubt, just use the tl072 :P.
John... your undrilled PCBs
(http://img23.photobucket.com/albums/v70/jojod818/GC%20Dual%20Mono%20Amp/Pcb0000.jpg)
cool... O0
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para saan yung pcb sa itaas?
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Getafix: that's for the power supply O0
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jojo,
bro, just wana ask how much you charge for designing pcbs from schematics? :) i found a schematic of a bass guitar preamp with a 3 band equalizer on the net also using tl072 chips. maybe i can email you the schematics if you like. all i need is the pcb foil layout. i can prepare the pcb myself. ;D
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jojo,
bro, just wana ask how much you charge for designing pcbs from schematics? :) i found a schematic of a bass guitar preamp with a 3 band equalizer on the net also using tl072 chips. maybe i can email you the schematics if you like. all i need is the pcb foil layout. i can prepare the pcb myself. ;D
It depends actually on the scope or the complexity of the circuit. Can we address this matter next week? Very busy, unfinished projects all-around. I'll just PM you when I'm ready.
JojoD
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Luciano Pavarotti and stereo GC + BPGC setup, what an experience indeed! O0 hairs rising.
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JojoD,
If you're not busy, is it possible to do the driver board of ST70? If you can, is there any locally available FR4 pc board instead of phenolic?
Regards.... :D :D :D
It depends actually on the scope or the complexity of the circuit. Can we address this matter next week? Very busy, unfinished projects all-around. I'll just PM you when I'm ready.
JojoD
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JojoD,
If you're not busy, is it possible to do the driver board of ST70? If you can, is there any locally available FR4 pc board instead of phenolic?
Regards.... :D :D :D
Sorry no FR4 available. I only use what's locally available.
A year ago, some guy ordered several pcb of the ST70 though. ;)
(http://img23.photobucket.com/albums/v70/jojod818/Dump/ST70.jpg)
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Hhmmm.... ::) ::) ::) Interesting.... OK, can you make me for this? PM me, how much will it cost thanks....
Sorry no FR4 available. I only use what's locally available.
A year ago, some guy ordered several pcb of the ST70 though. ;)
(http://img23.photobucket.com/albums/v70/jojod818/Dump/ST70.jpg)
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Hhmmm.... ::) ::) ::) Interesting.... OK, can you make me for this? PM me, how much will it cost thanks....
Sorry, can't do that now. Very busy with projects. :(
Maybe next time.
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It depends actually on the scope or the complexity of the circuit. Can we address this matter next week? Very busy, unfinished projects all-around. I'll just PM you when I'm ready.
JojoD
bro, the circuit isnt all that complex but ive no experience in designing pcbs. always did those projects with pcbs already laid out. anyway will wait for your pm next week. will concentrate on the amps na lang muna. thanks!
by the way, ive a question concerning power supplies. if youve a circuit that requires -6 +6VDC voltage source, can you connect it to a 0 +12VDC supply? was going around handyman and saw this AC to variable DC voltage supply (0 to 6, 9, 12VDC, 3A) and was wondering if i could use it for testing purposes, before i decide to buy em trafos. ::) ::)
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bro, the circuit isnt all that complex but ive no experience in designing pcbs. always did those projects with pcbs already laid out. anyway will wait for your pm next week. will concentrate on the amps na lang muna. thanks!
by the way, ive a question concerning power supplies. if youve a circuit that requires -6 +6VDC voltage source, can you connect it to a 0 +12VDC supply? was going around handyman and saw this AC to variable DC voltage supply (0 to 6, 9, 12VDC, 3A) and was wondering if i could use it for testing purposes, before i decide to buy em trafos. ::) ::)
If a circuit requires a "plus and minus" supply, then that means the "plus and the minus potentials" are referenced to ground. Meaning you have a voltage that is positive with respect to ground and negative with respect to ground.
If you use a 0 +12Vdc as your supply, your ground reference would be 1/2 of B+ (12V/2)because you will connect your 0 to your circuit's V-, you can get away with this by using a voltage divider so that your circuit can be referenced to 1/2 of B+ and use that as your ground. Don't jump yet and go buying that PSU, there are a lot of this to be considered and I don't think this forum is up to it.
However, such risks are done when there is absolutely no way of finding a decent +/- PSU. Besides, it will complicate your circuit especially if you will use opamps.
For benchwork, I sugget that you go and buy a 1-2 ampere trafo, 12-0-12 is good for usual electronic work. With this trafo, you can build a +/- supply or a 0 +12V, may come in handy especially for testing parts. Didn't you buy EE magazines? Volumes 1 & 2 have PSU for benchwork I think.
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jojo,
yeah i saw those projects on EE but was wondering if theres a way for me to test the amps (finished na pala but not yet bridged ;D ;D ) and check if they are working properly. wana make sure the amps are working fine before investing on the PSU and the preamp. is there a way for me to test them using a 0 - 12VDC supply? if not then i guess gonna have to go make the PSU.
by the way, rod elliot replied to my email and he said he did not have a ready pcb for the bridge on his site but i think i can design one. the circuits pretty simple. just bought the tl072 chip and the resistors needed.
thanks for helping out bro. O0
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jojo,
yeah i saw those projects on EE but was wondering if theres a way for me to test the amps (finished na pala but not yet bridged ;D ;D ) and check if they are working properly. wana make sure the amps are working fine before investing on the PSU and the preamp. is there a way for me to test them using a 0 - 12VDC supply? if not then i guess gonna have to go make the PSU.
by the way, rod elliot replied to my email and he said he did not have a ready pcb for the bridge on his site but i think i can design one. the circuits pretty simple. just bought the tl072 chip and the resistors needed.
thanks for helping out bro. O0
Don't use 0 12V in testing your gc amps or you'll have a huge dc offset at the output. Just buy a cheap 12-0-12 / 1A trafo, 4 diodes, and 2 pcs 4,700uf/50V caps and build a benchpsu. Good enough for testing and other uses such as opamp circuits like Rod's.
Rod is a very nice guy, very responsive too. Just build his circuit using PC201 boards for easier building.
Also, try building it one at a time. First thoroughly test your gc amps before proceeding in bridge config.
Goodluck,
JojoD
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For your indulgence John...
(http://img23.photobucket.com/albums/v70/jojod818/GC%20Dual%20Mono%20Amp/Pcb01.jpg)
(http://img23.photobucket.com/albums/v70/jojod818/GC%20Dual%20Mono%20Amp/Pcb02.jpg)
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For your indulgence John...
(http://img23.photobucket.com/albums/v70/jojod818/GC%20Dual%20Mono%20Amp/Pcb01.jpg)
(http://img23.photobucket.com/albums/v70/jojod818/GC%20Dual%20Mono%20Amp/Pcb02.jpg)
Yummy O0
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Jojo,
Sir pag finish na yan session ulit..
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Jojo,
Sir pag finish na yan session ulit..
Syempre naman! Hehehe, may dahilan na ulit eh.
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Jojo,
kailangan may dahilan tayo kung wala wala din session.. :'( :'(
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the capacitors in the project shall remain secret (but they are cheaper than black gates)hehehe
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I think I've read it somewhere on the net, removing the plastic covering of the caps.
can have some benefits.
I forget where.
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Here are some pic of what I'm working on.
(http://groups.msn.com/_Secure/0TADZAvMVeDYEd0EyseX47yWxO45fqZVLkmCTNmAN*6SYjpX8PYi0d8hBPLjjH6zSQ6CocU8Oq9HYOE*!uOwFRD*w41CTJAPVsJS5!VcWfP9i3eURdAoxEw/OPA541%20Bridges.jpg?dc=4675472453456126902)
GC based on the OPA 541 plan to do bridge-parallel. (Still need to buy alot of Caps)
(http://groups.msn.com/_Secure/0TwDbAkgYj!FXBuRdMlaj4DUU!g1fsgsUT9TkxVuGLVgIYwYZ6sfF*nKOB8!BjdtUyiB0RHS138Joxnchx1ZvCfVX7fGYoOa!BMcvaa8R*22AoZ4!b3J0OA/Assorted%20Projects.jpg?dc=4675472453617883324)
*Upper left OPA549 stereo GC, Upper Right OPA541 stereo GC, Mid left Active subwoofer controller, Lower left ESP Active subwoofer controller, Lower Right ESP 24dB/Octave 2 way Linkwitz-Riley Electronic Crossover.
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Here are some pic of what I'm working on.
*Upper left OPA549 stereo GC, Upper Right OPA541 stereo GC, Mid left Active subwoofer controller, Lower left ESP Active subwoofer controller, Lower Right ESP 24dB/Octave 2 way Linkwitz-Riley Electronic Crossover.
Dami nyan ah, penge naman.... ;D
Siguro puro dual voice coil subs mo! Congrats on your endeavor FASTBACK.
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Jojo,
kailangan may dahilan tayo kung wala wala din session.. :'( :'(
sus! gagawa ako ng madaming dahilan! hahahaha
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I think I've read it somewhere on the net, removing the plastic covering of the caps.
can have some benefits.
I forget where.
peter daniel stated that on one of the threads in diyaudio...even the gaincard's caps have their covers removed.
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the capacitors in the project shall remain secret (but they are cheaper than black gates)hehehe
need to remove the plastic, don't want to share the brand eh. hahahaha
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sus! gagawa ako ng madaming dahilan! hahahaha
Heard the hybrid GC you made for Akyat last saturday :) napaka gandang mga dahilan ang nagagawa mo bro!
Galing! :)
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soon we will have a hybrid, minimalist with dual mono power supply and monoblocks all ready....i smell another session O0
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Here are some pic of what I'm working on.
(http://groups.msn.com/_Secure/0TADZAvMVeDYEd0EyseX47yWxO45fqZVLkmCTNmAN*6SYjpX8PYi0d8hBPLjjH6zSQ6CocU8Oq9HYOE*!uOwFRD*w41CTJAPVsJS5!VcWfP9i3eURdAoxEw/OPA541%20Bridges.jpg?dc=4675472453456126902)
GC based on the OPA 541 plan to do bridge-parallel. (Still need to buy alot of Caps)
(http://groups.msn.com/_Secure/0TwDbAkgYj!FXBuRdMlaj4DUU!g1fsgsUT9TkxVuGLVgIYwYZ6sfF*nKOB8!BjdtUyiB0RHS138Joxnchx1ZvCfVX7fGYoOa!BMcvaa8R*22AoZ4!b3J0OA/Assorted%20Projects.jpg?dc=4675472453617883324)
*Upper left OPA549 stereo GC, Upper Right OPA541 stereo GC, Mid left Active subwoofer controller, Lower left ESP Active subwoofer controller, Lower Right ESP 24dB/Octave 2 way Linkwitz-Riley Electronic Crossover.
Ganda ha... kulang na lang ng magandang enclosure...
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Heard the hybrid GC you made for Akyat last saturday :) napaka gandang mga dahilan ang nagagawa mo bro!
Galing! :)
Hopefully magandang dahilan din mga upcoming projects ko. I am seriously studying the posibility of building a tube equalizer for akyat! hahahahaha
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soon we will have a hybrid, minimalist with dual mono power supply and monoblocks all ready....i smell another session O0
Sama kami dyan! ;D
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Don't use 0 12V in testing your gc amps or you'll have a huge dc offset at the output. Just buy a cheap 12-0-12 / 1A trafo, 4 diodes, and 2 pcs 4,700uf/50V caps and build a benchpsu. Good enough for testing and other uses such as opamp circuits like Rod's.
Rod is a very nice guy, very responsive too. Just build his circuit using PC201 boards for easier building.
Also, try building it one at a time. First thoroughly test your gc amps before proceeding in bridge config.
Goodluck,
JojoD
jojo,
yeah, i kinda figured a single supply wont do although i did get me the variable dc supply from handyman. needed a more powerful dc supply for future projects and also the power adapter i was using for my pcb drill conked out. anyway got me my trafo, diodes and caps and will test the amps one at a time like you said. by the way, do you still put mica insulators between ur opa549 chips and the heatsink? the technician at the electronic shop said i dont need to put em in anymore.
fastback,
galing workmanship mo bro. very tidy.
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Sama kami dyan! ;D
syempre O0
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jojo,
yeah, i kinda figured a single supply wont do although i did get me the variable dc supply from handyman. needed a more powerful dc supply for future projects and also the power adapter i was using for my pcb drill conked out. anyway got me my trafo, diodes and caps and will test the amps one at a time like you said. by the way, do you still put mica insulators between ur opa549 chips and the heatsink? the technician at the electronic shop said i dont need to put em in anymore.
fastback,
galing workmanship mo bro. very tidy.
No mica insulator?!? My goodness! Well all opa chipamps has their metal tab connected to V-, you'll find soon enough kasi if you donot use mica, your V- will be shorted to ground dahil I recommend you ground your heatsink for protection against possible oscillations (trust me on this, I use to do this for fun) and your full V+ will be applied to your speakers! Toasted tweeters anyone!
The datasheet recommends NOT to use mica insulators BUT the heatsink/chipamp assembly must be ISOLATED from the chassis or your chips go BOOM. Personally, I don't do this becoz I always connect my heatsinks to ground. I'll say it again, I do this due to oscillations. SEE bottom story.
My golly banana, baka di pa nababasa nun technician yun datasheet ng chips mo kaya nag arrive sya sa recommendation na yun! And please, do read the datasheet too.
Weird amp story: Oscillation
It was 1988, and I was building the electronic enthusiast 100W incredible amplifier project. It wasn't my first amp, but it sure is the biggest and most powerful of all my amp projects then. To make the story short, it worked the first time I powered it up, bias is good and for so many years it served it's purpose. However, I noticed that it's very hot, even without music. I used original Motorola parts (On semi was Motorola before) so I said maybe it's the design that causes the amp to heat up.
When I had some basic education of amplifier classes in college, I remembered that EE amp to be a Class AB design, meaning it shouldn't heat up like that when not playing. So armed with new knowledge, I dissected my incredible amp. Days past but no luck, fortunately, a classmate offered the use of his oscilloscope and to our surprise, the darn amp was oscilating like crazy. Can you guess what caused the oscillation? It was the heatsink not being grounded! For six years that amp worked while oscillating! Up to this day, that amp works fine but without that pestering oscillation.
I have experience this too when I was working on a Pioneer AN214 gc amp, so from then on, I always ground my amp's heatsinks, may it be a chipamp or a discrete ss amp.
I hope we all learn from this lesson. ;D
Sincerely,
JojoD
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jojo,
tnx bro. i just wanna make sure i dont get fireworks all over the place when i test my amp. :o :o was wondering why the guy told me mica insulation wasnt needed anymore. to make sure, i tested continuity of the ground pin and the metal tab and i realized that the metal tab wasnt supposed to be grounded. anyway ive got my mica insulators ready. the PSU is working ok, reading 0-25-50 Vdc. ive got my pcb for the bridge. got me a 7812 regulator IC for for my preamp power source, borrowed a mic preamp with tone controls from a friend so hopefully, fingers crossed, my amp will be working in 1 - 2 days. wish me luck. ;D ;D
p.s.
i always forget to discharge those big capacitors. :o O0
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jojo,
tnx bro. i just wanna make sure i dont get fireworks all over the place when i test my amp. :o :o was wondering why the guy told me mica insulation wasnt needed anymore. to make sure, i tested continuity of the ground pin and the metal tab and i realized that the metal tab wasnt supposed to be grounded. anyway ive got my mica insulators ready. the PSU is working ok, reading 0-25-50 Vdc. ive got my pcb for the bridge. got me a 7812 regulator IC for for my preamp power source, borrowed a mic preamp with tone controls from a friend so hopefully, fingers crossed, my amp will be working in 1 - 2 days. wish me luck. ;D ;D
p.s.
i always forget to discharge those big capacitors. :o O0
GOOD LUCK! >:D Hehehe
You'll always get sparks on those big caps. Try putting a 4.7K-10K 5W resistor between V+ and V-, that will discharge your caps slowly when you turn off your psu.
Again, good luck, your gonna need it dude.
JojoD
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jojo,
the amps are working great! and no fireworks, hehehe. theyre very nice sounding and no hum. am used to PAs with very, very slight hums in the background. did the bridge using pcb 201 like you said but forgot to get 7815 and 7915 regulators for it.
by the way, ive additional questions bro. ;D ;D
1) saw four 10,000uF caps on your PSU pic. is that an RC filter? or just caps in parallel? for high current applications, are there other ways of reducing voltage ripple aside from using bigger caps and RC filters?
2) what cap values (input and output) do u usually use for your regulators?
haaay, bridge testing na lang and casing. crossing fingers again. ;D ;D
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jojo,
the amps are working great! and no fireworks, hehehe. theyre very nice sounding and no hum. am used to PAs with very, very slight hums in the background. did the bridge using pcb 201 like you said but forgot to get 7815 and 7915 regulators for it.
by the way, ive additional questions bro. ;D ;D
1) saw four 10,000uF caps on your PSU pic. is that an RC filter? or just caps in parallel? for high current applications, are there other ways of reducing voltage ripple aside from using bigger caps and RC filters?
2) what cap values (input and output) do u usually use for your regulators?
haaay, bridge testing na lang and casing. crossing fingers again. ;D ;D
1. Used that just for testing. It is in parallel. Aside from using big caps, regulate your supply. RC filters are not usefull in high current apps. Better regulate your supply. But you can also use an unregulated for testing only.
2. 100-470uf input, 1uf//0.1uf output. Note: this usually depends in the "location" of your regulators with respect to your bridge and main filter caps.
To minimize crossing your fingers, triple check everything, I hate to hear that you injured your fingers due to too much criss-crossing. ;D
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1. Used that just for testing. It is in parallel. Aside from using big caps, regulate your supply. RC filters are not usefull in high current apps. Better regulate your supply. But you can also use an unregulated for testing only.
2. 100-470uf input, 1uf//0.1uf output. Note: this usually depends in the "location" of your regulators with respect to your bridge and main filter caps.
To minimize crossing your fingers, triple check everything, I hate to hear that you injured your fingers due to too much criss-crossing. ;D
the bridge worked! though am getting hum now. ??? browsed through rod elliots comments on the bridge, medyo delikado pala if the speakers are not connected properly or if you ground one of the terminals, masira daw ang amps. anyway, how bout connecting them in parallel and connect them to a 4-ohm load (two 12" 8-ohm speakers in parallel). would this be better? safer? thanks!
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the bridge worked! though am getting hum now. ??? browsed through rod elliots comments on the bridge, medyo delikado pala if the speakers are not connected properly or if you ground one of the terminals, masira daw ang amps. anyway, how bout connecting them in parallel and connect them to a 4-ohm load (two 12" 8-ohm speakers in parallel). would this be better? safer? thanks!
i never had any problems with my bridged gc amps, hopefully never ever.
there must be something wrong with your amp that would explain for the hum.
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hmmm..will check my work again. will post updates soon ...
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hmmm..will check my work again. will post updates soon ...
keep your fingers crossed. >:D
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Dual Mono GC, PSU via umbilical cord. Torture, ehem break-in period ;D.
(http://img23.photobucket.com/albums/v70/jojod818/GC%20Dual%20Mono%20Amp/AJ-GC0001.jpg)
(http://img23.photobucket.com/albums/v70/jojod818/GC%20Dual%20Mono%20Amp/AJ-GC0002.jpg)
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so far so good... as expected, a bit airy but not that sibilant in terms of sonics. no thump during turn-on/off, DC offset 7mV and 6mV, stepped attenuator looking good too. will keep it playing non-stop until friday night.
(http://img23.photobucket.com/albums/v70/jojod818/GC%20Dual%20Mono%20Amp/AJ-GC0003.jpg)
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update on my OPA subwoofer :)
(http://groups.msn.com/_Secure/0QgApA1gTz4A5f2m1GuOVdnlStPTdxdtPReIT5UGW1Di!ziO5R1yRZqNvad64PRVWLllZu6vIoOuNH3jgW0f8Ryz8TdfwivUaH2YNX8jSdlM/opasub.JPG?dc=4675472973323549709)
i used cables on old ps unit of PC . kasama pati yung connector
(http://groups.msn.com/_Secure/0RwDrAkAV0AQ5f2m1GuOVdtwjHm6rzuzmUCoHNi3yTnZDk1sZj3mBZzp6ibrxE!o8iwz7!S9V8E3IalgOUoYbjIgH5SJbl5adSEdOAzJXH8E/opasubnbox1.JPG?dc=4675472973508753471)
low pass filter and amps detached from the sub enclosure
(http://groups.msn.com/_Secure/0RwDrAkEVCwU5f2m1GuOVdpK*bCE9Y2SdZXbpZdOw1gvp0GnVt9yRIuWou6vkfzw3pHaUaD3icNzveVr6dtxWBnavIiYOfNSRF4PythNRthU/opasubnbox2.JPG?dc=4675472973606042433)
subok pa lang i-mount ;D
(http://groups.msn.com/_Secure/0RwDcAkIVRgU5f2m1GuOVdiZ1nhx503zJBN6sGR*uX3iCSlL112wTc7LZemRkde4sPUHWSNUh206Z8D3qXGuJpWx4sULFHRCAjyEfQ5zzvGA/opasubnbox3.JPG?dc=4675472973689460243)
amp's PS unit
(http://groups.msn.com/_Secure/0SwCLAt0VrTWSd7Y2LoHWPHijscVMfy0oN3LQowS3ORGmzC5JuqIe7dlzaJQOk8fCXz4BnvGnELNP0xIVhKNGTlsR6vdDjNNdOPmeSIimVGwmYaCwggb!yw/nut%20w%20studs.JPG?dc=4675472973833521399)
as recommneded by rod elliott, i used nuts with studs for subwoofer mounting.
sana matapos ko na ;D ;D
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they call those screw sets "T-nuts". standard issue on imported subs.
cool project btw.
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they call those screw sets "T-nuts". standard issue on imported subs.
Now, i know ;D
cool project btw.
Jojo, thanks :)
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Now, i know ;D
Jojo, thanks :)
sabi na i-glue mo yun mga wires eh. hehehe ;D
those wires/loose parts are notorious for rattles whether your sub is sealed or ported.
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sabi na i-glue mo yun mga wires eh. hehehe ;D
those wires/loose parts are notorious for rattles whether your sub is sealed or ported.
subok pa lang, hindi pa yan final ;D
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Dual Mono GC, PSU via umbilical cord. Torture, ehem break-in period ;D.
(http://img23.photobucket.com/albums/v70/jojod818/GC%20Dual%20Mono%20Amp/AJ-GC0001.jpg)
(http://img23.photobucket.com/albums/v70/jojod818/GC%20Dual%20Mono%20Amp/AJ-GC0002.jpg)
cool pics..can't wait to hear the amp in action...hope it passes the torture este breakin period hehe ;D
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cool pics..can't wait to hear the amp in action...hope it passes the torture este breakin period hehe ;D
break-in muna with Ottmar Liebert, then torture test with Evanescence and Linkin Park. ;D
i hope it survives too. ;)
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so far so good... as expected, a bit airy but not that sibilant in terms of sonics. no thump during turn-on/off, DC offset 7mV and 6mV, stepped attenuator looking good too. will keep it playing non-stop until friday night.
(http://img23.photobucket.com/albums/v70/jojod818/GC%20Dual%20Mono%20Amp/AJ-GC0003.jpg)
sir ang liit nitong amp na 'to ha, konti lang ang laki sa CD... congrats john5479!
can't wait to be shocked by its big sound...
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akyat,
parang i smell a session ;D
dadaanan na naman ng bagyo yan condo mo! ;D
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John,
Congrats in advance break in stage na pala...
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John,
Congrats in advance break in stage na pala...
After 24 hours continous playing, highs are taming and more defined while the mids are still open. Mamya bugbugin ko na. hehehe ;D
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rmpmla,
Sir ayos yan project mo... sub
JojoD,
Sir grabe naman yan 24/7 ba naka on... dapat sir makakuha ka nun magic cd.. for break in purpose talaga..
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rmpmla,
Sir ayos yan project mo... sub
JojoD,
Sir grabe naman yan 24/7 ba naka on... dapat sir makakuha ka nun magic cd.. for break in purpose talaga..
Ganun talaga pag ss gear, long hours of break-in. sino meron nun magic cd? cc naman... ;D sawa na ako Ottmar Liebert, magdamag yun ang music eh.
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dapat banatan yan ng enya alternating with evanescence hehe
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dapat banatan yan ng enya alternating with evanescence hehe
sumakit nga ulo ko sa Linkin Park eh. dapat nga Enya para swabeng mabangis. ;D
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so far so good... as expected, a bit airy but not that sibilant in terms of sonics. no thump during turn-on/off, DC offset 7mV and 6mV, stepped attenuator looking good too. will keep it playing non-stop until friday night.
slight typo error above. the dc offset should read as 0.7mV and 0.6mV.
tonight, the dc offset is down to 0.2mV and 0.15mV respectively.
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slight typo error above. the dc offset should read as 0.7mV and 0.6mV.
tonight, the dc offset is down to 0.2mV and 0.15mV respectively.
well at least there is a reason to the gainclone improving the longer you use it....the offset has gone down 8)
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well at least there is a reason to the gainclone improving the longer you use it....the offset has gone down 8)
the only difference between the 2 measurements was the higher readings were taken while the amp was cold while the lower reading was when the amp was warmed up. both measurements with 8 ohms load resistive.
it still sounds good btw. ;D
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the only difference between the 2 measurements was the higher readings were taken while the amp was cold while the lower reading was when the amp was warmed up. both measurements with 8 ohms load resistive.
it still sounds good btw. ;D
ah ok, i thought both measurements were taken while the amp was running...yes it will sound good hehehe O0
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JojoD,
Sir kindly pm SenyoR Don Kimpao he has a copy..
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JojoD,
Sir kindly pm SenyoR Don Kimpao he has a copy..
Okidoki, tnx!
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jojo,
good news! the bridged amp is working great. was troubleshooting cause of hum, saw a cold solder on one of my grounds. tried it in stereo mode (bridge not connected) with my nad cd player and my 8.1 diamonds, no hiss or hum whatsoever even set at full volume with no music playing. it sounds almost like my harman, although i got to admit the harman still sounds better in the bass department. i was considering using it as a stereo amp for my bedroom but am planning to make another gainclone using the lm3875 so bass amp na lang muna ito.
when connecting the two amps in bridge mode i can hear a very, very slight hiss, which u can only hear when your ear is 6 inches from the speaker. can this be caused by unequal voltage sources for the tl072 chip? +V is around 14.7V but my -V is 14.5V. Or probably because am not using quality components, lahat generic lang kasi. Anyway, the hiss is not that big a deal since you cant hear it a foot away from the speaker and itll only be used as a bass guitar amp.
also how hot is hot? the heatsink gets hot after several hours of use (bridged), volume set halfway from full. the heat is tolerable to my fingers for only about 3 seconds. or is this normal?
anyway, thanks a lot bro. success ang first project ko. bass preamp na lang and am ready to rock.
p.s.
hope you have time for my bass preamp pcb layout. ;D ;D ;D
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jojo,
good news! the bridged amp is working great. was troubleshooting cause of hum, saw a cold solder on one of my grounds. tried it in stereo mode (bridge not connected) with my nad cd player and my 8.1 diamonds, no hiss or hum whatsoever even set at full volume with no music playing. it sounds almost like my harman, although i got to admit the harman still sounds better in the bass department. i was considering using it as a stereo amp for my bedroom but am planning to make another gainclone using the lm3875 so bass amp na lang muna ito.
when connecting the two amps in bridge mode i can hear a very, very slight hiss, which u can only hear when your ear is 6 inches from the speaker. can this be caused by unequal voltage sources for the tl072 chip? +V is around 14.7V but my -V is 14.5V. Or probably because am not using quality components, lahat generic lang kasi. Anyway, the hiss is not that big a deal since you cant hear it a foot away from the speaker and itll only be used as a bass guitar amp.
also how hot is hot? the heatsink gets hot after several hours of use (bridged), volume set halfway from full. the heat is tolerable to my fingers for only about 3 seconds. or is this normal?
anyway, thanks a lot bro. success ang first project ko. bass preamp na lang and am ready to rock.
p.s.
hope you have time for my bass preamp pcb layout. ;D ;D ;D
you have to match the feedback networks and dc offsets of both amps in the bridge. otherwise, one amp will be conducting current on a continous state. that would explain your excessive heat dissipation.
i have checked my bridge parallel gc but i really have no hiss, hum, or whatever, just music, even at full volume.
I have your schematic, a bit complex due to the Baxandall tone controls. Maybe you can design it since one channel is what you need. It would be unfair for you to charge you for just the pcb design, and it would also be unfair for me to spend a lot of time designing and charge so little. I don't want to surprise you with the design fee. :o ;D
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testing my OPA powered sub
(http://groups.msn.com/_Secure/0RgD3AjQVOfxv5k8PjcN3c*Q0L*II8St*QFk9JgLjKx7evcfdNN6YLFTEnPSN12be!ulVbCLcs17m9gDG0i4qi1KcMMxThkWHWkLGIIYXJKU/subonsetup.JPG?dc=4675473395452294727)
close up
(http://groups.msn.com/_Secure/0RQAkA8AU99z55iuDV*yxkNnBd*RUXkcZwb*9LS1rwsAyd9ZvOUVpPSORiut4LTh8zVc1NQkAIWNCiXmy6iDeEoi3!XBtafcJANpCMGePo9U/frontview.JPG?dc=4675473395379195974)
noticed heat build up on the area where 4-OPAs are located. remedyo ;D
(http://groups.msn.com/_Secure/0SwAAADUXh41grBIbJgBL*yk3G5fsmHWG2LPcqd*mULUoHBxNOqtG1ImYMVzcBem1qMce803IOzalhtWIfnVQ8wozdQd6C5HpkAqeGFfZ7fDXJgcR7aVYVg/heatsinkwblower.JPG?dc=4675473395190222185)
good bass with no noticeable distortion even at high volume :)
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great job!
ok sa remedyo ah. ;D
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you have to match the feedback networks and dc offsets of both amps in the bridge. otherwise, one amp will be conducting current on a continous state. that would explain your excessive heat dissipation.
i have checked my bridge parallel gc but i really have no hiss, hum, or whatever, just music, even at full volume.
I have your schematic, a bit complex due to the Baxandall tone controls. Maybe you can design it since one channel is what you need. It would be unfair for you to charge you for just the pcb design, and it would also be unfair for me to spend a lot of time designing and charge so little. I don't want to surprise you with the design fee. :o ;D
jojo,
hehehe, i guess ill have to do it mano mano. been getting tips on pcb layouting from the net. tnx neway bro. ;D
i did test the bridge for dc offsets pero analog lang kasi ang multimeter ko. not very accurate when it comes to milivolt measurements.
rmpmla,
nice job! how many opa chips did you use for your sub bro? is it in bridge - parallel configuration also? how many watts is the whole amp? TIA :)
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got an idea from hans to burn-in my tube preamp using my radio tuner as input because i didn't want to run my CD player on repeat for extended hours... so i thought why not burn-in my hybrid gainclone at the same time?
so off to the bedroom they went, where they are to play overnight everynight for the next 2 weeks... first impressions: the combi consisting of a hybrid gainclone, sansui vintage tuner, AMX tube buffer/preamp and MS-902 speakers... sounds awesome in my small bedroom! nicely balanced highs, mids and bass... its a great feeling to wake up to morning radio.
i hate to say this coz i also own it -- master jojo, you have beaten my stereophile recommended hybrid luxman lv-105.
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got an idea from hans to burn-in my tube preamp using my radio tuner as input because i didn't want to run my CD player on repeat for extended hours... so i thought why not burn-in my hybrid gainclone at the same time?
so off to the bedroom they went, where they are to play overnight everynight for the next 2 weeks... first impressions: the combi consisting of a hybrid gainclone, sansui vintage tuner, AMX tube buffer/preamp and MS-902 speakers... sounds awesome in my small bedroom! nicely balanced highs, mids and bass... its a great feeling to wake up to morning radio.
i hate to say this coz i also own it -- master jojo, you have beaten my stereophile recommended hybrid luxman lv-105.
akyat,
i myself love it's warmth and detail. nice to hear you enjoy the sound of the hybrid gc too.
and yes, tuner's white noise (those off frequency noise you hear when changing frequency) is the best break-in frequency for it contains an almost complete frequency spectrum.
hybrid gc + coffee = very good morning ;)
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great job!
ok sa remedyo ah. ;D
Jojo, thanks. :)
have to address the heat build up since i squeezed in all the OPAs, low pass filter (and the its power supply ) on a single heat sink. after turning on the sub for a few minutes, the heat sink becomes hot particularly on the area where 4-OPAs are located. once you drive the sub at high volume, distorted sound is produced. was thinking of changing the heat sink and the parts layout, kaya lang tinatamad na ko ;D
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rmpmla,
nice job! how many opa chips did you use for your sub bro? is it in bridge - parallel configuration also? how many watts is the whole amp? TIA :)
thanks cousin skeeter :)
i used 4 - OPA549 in parallel+bridge configuration . my guestimate ;D , its about 200 watt rms.
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rmpmla,
Sir ayos yan project mo... sub
Thanks :) . Actually, was planning to make a stereo amp using OPA549 in bridge+parallel config.
but i got excess plywood, MDF board and a pair of cheap 15" subwoofers. kaya subwoofer project muna inuna ko.
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Jojo, thanks. :)
have to address the heat build up since i squeezed in all the OPAs, low pass filter (and the its power supply ) on a single heat sink. after turning on the sub for a few minutes, the heat sink becomes hot particularly on the area where 4-OPAs are located. once you drive the sub at high volume, distorted sound is produced. was thinking of changing the heat sink and the parts layout, kaya lang tinatamad na ko ;D
try this...
1. short the input of your lpf to ground.
2. switch on the sub's psu and let it warm up.
3. monitor the temperature of your heatsink every ten minutes.
with no signal input, your heatsink (12" i guess) should be adequate for idle and medium duty sub work. if it heats up to some degree that you cannot even touch the heatsink (no signal input), then you need to check for dc offset per 549 amp module. Either one of those amps are sucking in current through offset voltage.
HTH, congrats again,
JojoD
PS, with properly "aligned" gc modules in bridge/parallel, those heatsinks should be good enough for HT but may need the fan if will be used for music.
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jojo,
hehehe, i guess ill have to do it mano mano. been getting tips on pcb layouting from the net. tnx neway bro. ;D
i did test the bridge for dc offsets pero analog lang kasi ang multimeter ko. not very accurate when it comes to milivolt measurements.
you may need to find a better way of measuring those offsets down to the millivolts that they are. good hunting... ;)
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try this...
1. short the input of your lpf to ground.
2. switch on the sub's psu and let it warm up.
3. monitor the temperature of your heatsink every ten minutes.
with no signal input, your heatsink (12" i guess) should be adequate for idle and medium duty sub work. if it heats up to some degree that you cannot even touch the heatsink (no signal input), then you need to check for dc offset per 549 amp module. Either one of those amps are sucking in current through offset voltage.
HTH, congrats again,
JojoD
PS, with properly "aligned" gc modules in bridge/parallel, those heatsinks should be good enough for HT but may need the fan if will be used for music.
try ko to this weekend :)
the 4 OPAs were not laid out evenly on the heat sink. willl try to change the layout on my next sub project.
(http://groups.msn.com/_Secure/0SQDfAp4VJSHcOkHSGIAlDuhgW4h1Hzwm!wJ2x9cgrFIuKAYydFlyRod*bDywVi7rBBgerVJEES5xJepPE4MK!RFVvDuynxir3rin02YgcoiwGsnEZPtljg/opaclose%20up.JPG?dc=4675473588563293531)
thanks for the suggestions :)
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Congrats on your sub project rmpmla.... ;) ;) ;)
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could I use the transformers that are used by computer PSU in powering the OPA549... I've never opened a computer PSU before
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rmpmla
Congrats on doing a nice work on your sub project. I know you could sort things out.
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guys,
just downloaded circuitmaker 2000. after creating the schematic of the amp bridge adapter, it automagically made a pcb layout with its autorouter. it has a 30 day limit but then again there are always "ways" to go around "30 day limits" ;) ;) ;). cant wait to test it with my preamp schematic when i get home. >:D >:D >:D
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Congrats on your sub project rmpmla.... ;) ;) ;)
rmpmla
Congrats on doing a nice work on your sub project. I know you could sort things out.
s2kov, FASTBACK - thanks :)
this is the finished project :
(http://groups.msn.com/_Secure/0VwANA7Qa0LPduZ*kz7gpm81iFC*sOC4kdXtJl7djAqfHpScdxKsLcts3ExEJ*TkdXkbgSqpqYyE6X1Xx!4797nIQ*j1!*0uIhvulWTxrxffuHWk6vapPUiuaDXlxGNJF/finished%20opa%20poweredsub.JPG?dc=4675473656490019520)
i bought one roll of black PVC laminate at ACE worth P119.00 and spray painted the speaker to dark color.
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could I use the transformers that are used by computer PSU in powering the OPA549... I've never opened a computer PSU before
i have not tried it yet :). pero mukhang hindi uubra ;D.
what was useful for me with PC's PSU are the cables and its connectors.
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multi tap ba ang transformer ng PSU? if so, ilan?
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nice job with that 2nd sub rmpmla. like my sub projects, i like veneering more than painting, after sticking those panels listening tests na agad, no more waiting for paint to cure!
maybe i can take some pics of my subs later, kakatamad kalasin, naka setup na kasi. ;D
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I would like to congratulate jojod18 for a project well done....the gainclone i got sounds good...it excels in vocals, worked better with my amx preamp O0
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more thoughts on the gainclone: The amp is not as dry as other ss amp and sounds airy but not as lush as my monoblocks. its not really a bad thing as some might prefer a more neutral midrange. for the price this amp is worth every penny and can compete with more expensive amps. the only nitpicks is that this amp needs easy to drive speakers or speakers with steady impedance loads for it to work its best, much like low pwered tube amps ;D
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nice job with that 2nd sub rmpmla. like my sub projects, i like veneering more than painting, after sticking those panels listening tests na agad, no more waiting for paint to cure!
this is the same sub i posted earlier. just spray painted the red speaker cone to black ;D. you are right, much easier to use those PVC laminates than painting the box.
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I would like to congratulate jojod18 for a project well done....the gainclone i got sounds good...it excels in vocals, worked better with my amx preamp O0
john, the pleasure was all mine. :)
good to hear you liked the amp as I did. session time?
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could I use the transformers that are used by computer PSU in powering the OPA549... I've never opened a computer PSU before
no ... the pc psu is a switching power supply and uses high-frequency transformers which are very much unlike the usual line frequency (60Hz) tranformers used for gainclones
but there is really nothing to stop you from using a switching power supply with correct specs (if you can find or build one) for your gainclone ... those high-powered car audio amps use them, converting the 12VDC to +/- 35V or more
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no ... the pc psu is a switching power supply and uses high-frequency transformers which are very much unlike the usual line frequency (60Hz) tranformers used for gainclones
but there is really nothing to stop you from using a switching power supply with correct specs (if you can find or build one) for your gainclone ... those high-powered car audio amps use them, converting the 12VDC to +/- 35V or more
pc psu = very noisy... due to poor suppression of switching noise. ;D
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pc psu = very noisy... due to poor suppression of switching noise. ;D
have you heard the "switching noise" coming out of the speakers driven by an amp using an smps?
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have you heard the "switching noise" coming out of the speakers driven by an amp using an smps?
I didn't hear it exactly, just thought something wierd is happening in the highs, saw it with my eyes through an oscilloscope.
SMPS from a pc is very different from an SMPS inside a car amplifier if that's what your going into.
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I didn't hear it exactly, just thought something wierd is happening in the highs, saw it with my eyes through an oscilloscope.
SMPS from a pc is very different from an SMPS inside a car amplifier if that's what your going into.
I guess we are now on the same line of thinking. :)
Now just for curiousity, i hope you could tell me more about your pc-psu on an amp experience. What voltage did you use for the amp? I would guess 12 volts. If true, what did you do with the 5-volt output of the psu? I believe that using only the 12 volt output while the 5-volt is unloaded will indeed mess up the psu's regulation because, afaik, the feedback for regulation is coming from the 5-volt line. This might explain the anomally you've seen on your scope.
I've tried scope'ing the pc-psu outputs on actual pc operation and didn't see anything unsual, instead they are rock steady DC voltages as expected. Using the psu on an amp would be tricky, i think, because it would be necessary to load the 5-volt with similar current load as the 12-volt for the regulation to work properly. An amp is obviously a highly dynamic load as opposed to a pc motherboard, so making the 5-volt output to track the 12-volt load is the tricky part. On a pc, the 5-volt is mostly carrying the load. But not having the experience with an amp setup, all these are just my intuition. So i hope to hear from your side, if only to gain better understanding what is going on. Thanks.
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kinyo,
all i can remember when i tested a pc psu is that i used the 5 volts for logic circuits used for input control, quite a low load indeed. the amp used was a tda2030 connected in a non-inverting/single supply configuration. the amp worked, but not as i expected it to be. the pc psu was checked and found to be working so i tried a different supply for the amp and so it goes.
most of the gc amps i have worked on operated at +/- supplies and ifind them better than an amp using a single supply (maybe due OCL). i have never ventured again in using a pc psu for an amp mainly due to complications that arise thereof.
fwiw, this is just my opinion and shouldn't stop anyone from using a pc psu for an amp.
oh btw, there is this thing about amps and power supplies (maybe you already know this :)) and goes... "an amp is a modulated power supply, in a perfect world, power in is equal to power out". and those old guys even say "what you feed an amp is what you hear".
:)
JojoD
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thanks for the info, Jojo! :)
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jojo,
bass amp successful bro! hehehe. didnt make the bass preamp yet coz am not to sure if itll work and ive to optimize the pcb layout pa so i settled to making a simple mic preamp instead. sounds ok but am not too sure if its gonna be loud enough. will be using it in church too :).
hope my sis will be able to get them lm3875 sample chips. gainclone nman next project. :)
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Wanna see what's inside the 47 Lab's 4717 Shigaraki Integrated Amp? This thing costs $1980.
http://www.hifi.nl/recensies.php?id=1966
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(http://www.hifi.nl/gfx/47Labs_balk_270504.jpg)
(http://www.hifi.nl/gfx/47labs08_cl_270504.jpg)
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(http://www.hifi.nl/gfx/47Labs_balk_270504.jpg)
(http://www.hifi.nl/gfx/47labs08_cl_270504.jpg)
They also don't want to share the brand and values of the caps, ;D ;D ;D ;D ;D
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for a $1000 amp you'd think they could afford to hire people to do neater wiring ::)
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just goes to show that wiring does not totally affect the sound >:D (just being sarcastic)
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They also don't want to share the brand and values of the caps, ;D ;D ;D ;D ;D
Yes but in an interview, Junji said that 47 labs did not use any "audiophile" components so no black gate and the likes. The red cap behind the electrolytic looks like a WIMA mkp or mkt type.
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Gainclone vs. Audion Silver Night 300bs--one guy's OPINION only.
http://www.trutek-uk.com/Nicks_audio/audio.htm
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excellent read..... thanks for the link Garp.
john/jojoD.... ready na kayo sa shootout? ;D
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excellent read..... thanks for the link Garp.
john/jojoD.... ready na kayo sa shootout? ;D
sabihin lang kung saan O0
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3pm dis sat (sa bundok)!! attend ako ng binyag sa umaga up to tanghali eh.
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Are these LM1875 IC's I'm looking at? tsk... tsk... tsk...
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Are these LM1875 IC's I'm looking at? tsk... tsk... tsk...
yup lm1875's its cool how they are mounted as from the outside you won't see any screws on the side.
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guys,
question lang po. how do you get rid of the sound the speakers make a few seconds after you turn off the amp (opa549 mono bridged amp)? is it caused by the capacitors discharging?
also noticed that when turning my volume on my bass guitar from zero, at the very first tweak, theres a slight thump. its not the potentiometer coz i tried using the electric guitar, the thump is still there.
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They also don't want to share the brand and values of the caps, ;D ;D ;D ;D ;D
Not really. The maker of the amplifier confided to Peter Daniel that stripping off the capacitor has a substantial improvement on the sound. Perhaps you may try it if that is true.
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Not really. The maker of the amplifier confided to Peter Daniel that stripping off the capacitor has a substantial improvement on the sound. Perhaps you may try it if that is true.
it serves both ways, there is a sound benefit at the same time keeping the values secret ;D
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need to remove the plastic, don't want to share the brand eh. hahahaha
I was just reffering to JojoD post before.
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For your indulgence John...
(http://img23.photobucket.com/albums/v70/jojod818/GC%20Dual%20Mono%20Amp/Pcb01.jpg)
(http://img23.photobucket.com/albums/v70/jojod818/GC%20Dual%20Mono%20Amp/Pcb02.jpg)
Also referring to this project by jojoD from his previous post. :o :o :o :o :o
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Hi
Any idea on what type of IC is inside a Konzert (videoke amplifier).
Are those IC based or a discrete design. Thsi is sold at 3500 along Raon stores.
Would it be sufficient for a lm1875 for a videke machine?
I appreciate your help/suggestion.
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Hi
Any idea on what type of IC is inside a Konzert (videoke amplifier).
Are those IC based or a discrete design. Thsi is sold at 3500 along Raon stores.
Would it be sufficient for a lm1875 for a videke machine?
I appreciate your help/suggestion.
Those Konzert/Sakura/Hyundai videoke amps have 2SC5200/2SA1943 complimentary pair power transistors from toshiba. A shop owner at Raon said that the amp design is a hijacked version of a leading power amp manufacturer design. So he says.
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jojo,
bass amp successful bro! hehehe. didnt make the bass preamp yet coz am not to sure if itll work and ive to optimize the pcb layout pa so i settled to making a simple mic preamp instead. sounds ok but am not too sure if its gonna be loud enough. will be using it in church too :).
hope my sis will be able to get them lm3875 sample chips. gainclone nman next project. :)
congrats! finally it all paid off. whew!
good luck to yor sister too.
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3pm dis sat (sa bundok)!! attend ako ng binyag sa umaga up to tanghali eh.
sir,
count me in.
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jojo - when I was looking at your PCB layout, I just noticed that there was an extra capacitor and resistor connected to pin 4 of your OPA549 GC, what's that for? I am in the process of etching my own PCB (was finalizing my layout)
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Those Konzert/Sakura/Hyundai videoke amps have 2SC5200/2SA1943 complimentary pair power transistors from toshiba. A shop owner at Raon said that the amp design is a hijacked version of a leading power amp manufacturer design. So he says.
Hi Jojo,
Thanks for the info. sounds like P3A will do for a good videoke amp. What do you think? but gainclone is far more easier to build than the P3A.
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Hi Jojo,
Thanks for the info. sounds like P3A will do for a good videoke amp. What do you think? but gainclone is far more easier to build than the P3A.
Exactly! P3A is a very good choice for HT and videoke apps. This P3A version of mine uses TO-3 package power transistors simply because someone gave me that heatsink. Prerotica is the tube preamp used with this P3A.
(http://img23.photobucket.com/albums/v70/jojod818/P3A%20Power%20Amp/P3A_01_small.jpg)
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jojo - when I was looking at your PCB layout, I just noticed that there was an extra capacitor and resistor connected to pin 4 of your OPA549 GC, what's that for? I am in the process of etching my own PCB (was finalizing my layout)
i think this is the second time that i have to explain this... ;D
the cap is for blocking dc if source (cd player, preamp, etc.) contains dc. resistor sets input impedance.
HTH, JojoD
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i think this is the second time that i have to explain this... ;D
sorry about that... thanks for the quick reply though... :)
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Exactly! P3A is a very good choice for HT and videoke apps. This P3A version of mine uses TO-3 package power transistors simply because someone gave me that heatsink. Prerotica is the tube preamp used with this P3A.
(http://img23.photobucket.com/albums/v70/jojod818/P3A%20Power%20Amp/P3A_01_small.jpg)
how does this amp fare for audio? rod elliot says that this amp can compete with the best of them...any comments??
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John,
Kailan ba shootout ng gainclones.. balita ko this week ba??
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John,
The P3A is like the Leach amp, they are both more than 20 years old. ;D
Seriously, advancements in technology gave this amp a face-lift. A very good contender indeed. Aside from the reason that I already have the heatsink, the most important reason why I built this version of the P3A is for a shootout with an AKSA power amp. 8)
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peeps,
are the lm1875 chips sold in electronic stores here in pinas the same as the ones made by national semiconductor? are there such things as fake chips? called up a store here and its being sold for around P150/chip. thanks!
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peeps,
are the lm1875 chips sold in electronic stores here in pinas the same as the ones made by national semiconductor? are there such things as fake chips? called up a store here and its being sold for around P150/chip. thanks!
try it, if it blows up, then it's probably a fake. ;)
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peeps,
are the lm1875 chips sold in electronic stores here in pinas the same as the ones made by national semiconductor? are there such things as fake chips? called up a store here and its being sold for around P150/chip. thanks!
Yes LM1875 is abundant here. I've tried a couple and they're ok. But P150 per chip is expensive already. I got 2 at Raon (forgot the name of the store) for P99 a peice.
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garp,
thanks! but ive no choice, cant buy from raon coz not from manila. anyway siguro may tawad pa naman dun sa store.
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John,
Kailan ba shootout ng gainclones.. balita ko this week ba??
this sat. daw 3pm at akyat's place
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guys bukas ha.... dalhin nyo gc nyo.... 3pm.
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yep i'll bring my gainclone and my amx preamp as well ;D
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Yes LM1875 is abundant here. I've tried a couple and they're ok. But P150 per chip is expensive already. I got 2 at Raon (forgot the name of the store) for P99 a peice.
It's probably the 99 peso store? ;D
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guys bukas ha.... dalhin nyo gc nyo.... 3pm.
yup, i'll bring mine too.
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my brother bought for a project 15 tda2030, 10 tda2050, and 3 tda1514 at a small, no name shop in raon (yun daw 1m x 2m na shop) at unbelievable prices. the 1514s have philips markings and the 2050s has a small "st" mark with "sing" on the front while the 2030s just have "2030A" as a mark. all worked well except for the 6 out of 15 2030s. Factory defect daw sabi nun saleslady, just learned this evening about it though.
several times i've bought counterfeit transistors but only few occasions with ICs. just thought i share.
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so tiny and light it's a miracle that it sounds so BIG.
(http://203.131.66.146:8080/gc4.jpg)
the tiny chassis still has lots of space, you could make it 50% smaller.
(http://203.131.66.146:8080/gc5.jpg)
it doesn't get hot too, when i touched the sides where the chips are attached.... it's barely even warm.
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See, surface area is almost the same as the adjacent CD Case. Mas mahaba pa nga ang remote.
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Sir Akyat, musta ba yang amp na yan?....Ang LIIT nyan ahh.....review naman dyan sir?...baka pwede na magpa custom made nyan kay sir jojod818. Siguro kaya ko na price nyan....yung iniipon ko kung saan saan na napunta eh.. :'( gusto ko ng mag upgrade from my Konzert. Ilang watts ba yan sir?
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The gainclone amp in the pic was hooked up to a pair of mordaunt short 908's. Considering that the source was a denon surplus cd player...the sound was big....lots of details and only some hints of sibilance, one thing that's good with this amp was the bass it produced with the MS908's...deep but does not overpower the midrange and highs. The combo of the MS908, denon cd player and gainclone provided a very pleasant musical experience. ;)
Btw the gainclone on the pic can provide ~56 watts at 8 ohms this amp can give amps much more expensive than its total cost a run for its money.
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The gainclone amp in the pic was hooked up to a pair of mordaunt short 908's. Considering that the source was a denon surplus cd player...the sound was big....lots of details and only some hints of sibilance, one thing that's good with this amp was the bass it produced with the MS908's...deep but does not overpower the midrange and highs. The combo of the MS908, denon cd player and gainclone provided a very pleasant musical experience. ;)
Btw the gainclone on the pic can provide ~56 watts at 8 ohms this amp can give amps much more expensive that its total cost a run for its money.
:owwwwooowwwww!!! ~56watts sa ganyang kaliit na amp?..susme.....may option na naman ako ah....mga sir. how much po kaya yan?...baka kaya ko na ngayon yan!! Thanks :)
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pre akyat,
is that an lm3875 based gc? or opa549/541?
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cousin, i think jojoD used LM3875 on those.... tama ba master jojod?
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any pics of the powersupply used?
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here's a pic of the power supply.... its about the size of a small AVR.
(http://203.131.66.146:8080/gc8.jpg)
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it looks exactly like an AVR :)
would it be possible to use just one transformer for a 2 channel chip amp?
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getafix,
i used 1 trafo for my opa gc and its working ok. as long as its VA rating is more than sufficient to power two chips, it'll work. im just kinda wondering why some of the gc amp pictures ive seen on the net make use of two very large torroidal trafos when its only powering 50 watt chips amps. i know that bigger trafos make for better sound but isnt that taking it a bit too far?
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getafix,
i used 1 trafo for my opa gc and its working ok. as long as its VA rating is more than sufficient to power two chips, it'll work. im just kinda wondering why some of the gc amp pictures ive seen on the net make use of two very large torroidal trafos when its only powering 50 watt chips amps. i know that bigger trafos make for better sound but isnt that taking it a bit too far?
some just want a dual mono config for their gc's, and with the chips relatively cheap to begin with, one can opt to splurge on the other parts of the amp.
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guys,
I was present last Saturday shootout.. galing nitong babies ni JojoD and JOhn will be amazed with the Grand sound this 56 watters can do considering the MS908 side firing passive woofer parang naka 6inch lang hehehe tight and round yun bass tapos good part is high and mids are balance.. Congrats!! 8)
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cousin, i think jojoD used LM3875 on those.... tama ba master jojod?
correct ka dyan! i have built a lot of gcs and so far, it's the best i've heard.
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guys,
I was present last Saturday shootout.. galing nitong babies ni JojoD and JOhn will be amazed with the Grand sound this 56 watters can do considering the MS908 side firing passive woofer parang naka 6inch lang hehehe tight and round yun bass tapos good part is high and mids are balance.. Congrats!! 8)
hans, grabe yun cd mo! with this weather, tapos gc amp and your cd... bigla ako nakatulog!
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hans, grabe yun cd mo! with this weather, tapos gc amp and your cd... bigla ako nakatulog!
JojoD818 congrats for the very good reception on your gainclone. ;D
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JojoD,
Basta ikaw sir... tried pala John Gainclone sa house convinced panalo talaga! ;D ;D
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hmmnn can't wait for the lm1875 amp O0
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Hello. Did anyone try the gainclone with any high sensitivity low impedance speaker? I'm just wondering if its really the case as the reviewers say---that using gaincard with low impedance speakers take the Gaincard to a whole new level.
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Hello. Did anyone try the gainclone with any high sensitivity low impedance speaker? I'm just wondering if its really the case as the reviewers say---that using gaincard with low impedance speakers take the Gaincard to a whole new level.
malapit nang masubukan hehe ;D
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update:
TI just sent me 5 opa549s and 10 opa541s. their backorder process seems to be working fine. got me 15 chips to play around with. siguro will try making a 5 channel amp. ;D ;D ;D
i love TI!
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JojoD818 congrats for the very good reception on your gainclone. ;D
thank you, you should have been there too.
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JojoD,
Basta ikaw sir... tried pala John Gainclone sa house convinced panalo talaga! ;D ;D
that is good news! ;D it only means that it is a versatile amp.
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hmmnn can't wait for the lm1875 amp O0
pcb design is almost complete. i am finalizing the ground scheme though. ;D
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jojo,
question lang bro. been browsing pictures of gainclones and noticed that their PSUs dont use large capacitors. from the bridge rectifier with MUR860 diodes, they connect it to their gainclone pcbs and on their pcbs they only 1000uF or 2200uF caps. are the MUR860 diodes doing the work of big caps? am confused :-\ :-\
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jojo,
question lang bro. been browsing pictures of gainclones and noticed that their PSUs dont use large capacitors. from the bridge rectifier with MUR860 diodes, they connect it to their gainclone pcbs and on their pcbs they only 1000uF or 2200uF caps. are the MUR860 diodes doing the work of big caps? am confused :-\ :-\
nope, the diodes donot do any filtering, they just do what they do best - rectify. ;D
gc amps use small value caps due to high PSRR and besides, small caps add to the good sound.
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hmmm, now am really confused. big caps = good sound, small caps = good sound. :-\ :-\ :-\ by the way, ive been contacting all electronic shops here at my place but none of them have black gates or elna or even panasonic caps. never heard sila daw of black gates, akala nila wrong number tinawagan ko. ??? will have to stick with generic ones.
anyway, will go on ahead with my next gc. will be making use of lm1875s using rod elliots schematic. thanks again!
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hmmm, now am really confused. big caps = good sound, small caps = good sound. :-\ :-\ :-\ by the way, ive been contacting all electronic shops here at my place but none of them have black gates or elna or even panasonic caps. never heard sila daw of black gates, akala nila wrong number tinawagan ko. ??? will have to stick with generic ones.
anyway, will go on ahead with my next gc. will be making use of lm1875s using rod elliots schematic. thanks again!
There is this other theory that big caps can provide a slower sound but i guess it depends on the design of the circuit. The gainclone just happens to work better with a smaller value cap.
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There is this other theory that big caps can provide a slower sound but i guess it depends on the design of the circuit. The gainclone just happens to work better with a smaller value cap.
I think the law of diminishing returns applies to such a circuit too. In this case, less is more. Another reason why a minimalist gc sounds better.
As john says, a larger cap will make the sound slower therefore not ideal. I have experimented on this using different types and values of caps and I find the recommended value to be more pleasing.
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jojod18: how is the lm1875 prototype going?? ;D
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hmmm, now am really confused. big caps = good sound, small caps = good sound. :-\ :-\ :-\ by the way, ive been contacting all electronic shops here at my place but none of them have black gates or elna or even panasonic caps. never heard sila daw of black gates, akala nila wrong number tinawagan ko. ??? will have to stick with generic ones.
anyway, will go on ahead with my next gc. will be making use of lm1875s using rod elliots schematic. thanks again!
to prevent confusion, may I suggest that you first read and understand the chip's datasheet. there are a lot of data (maybe that's why they call it datasheet ;D) in there that can help you more.
beware, some local shops don't care about brand. i called a shop once asking for black gates and the saleslady on the other line shouted "bastos!" and then she slammed the phone. since then, i never mentioned the word black gates. i don't know why she went mad??? i never thought black gates can get you into trouble! ;D
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If you can find japanese brands for the caps they provide performance which is comparable with the exotic brands, and some may find the price diff. for improvement not worth it.
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jojo and john,
thanks guys. so far no one has slammed the phone on me naman ;D ;D. am reading the data sheets now and reading on psrrs, coupling and bypassing, etc. a lot of computation seems to be needed to have the ideal values for your caps but i think theres no harm just trying out different values.
by the way, where in manila do you usually get your black gates. might be able to have a friend buy for me na lang.
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your best bet is online or have a friend in the states buy it for you. there is no 1000 uf black gate cap easily available here unfortunately.
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john,
thought they were readily available there. tsk tsk tsk. any japanese brands you can recommend?
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the usual suspects...elna, rubycon and nichicon :)
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hmmm, now am really confused. big caps = good sound, small caps = good sound. :-\ :-\ :-\ by the way, ive been contacting all electronic shops here at my place but none of them have black gates or elna or even panasonic caps. never heard sila daw of black gates, akala nila wrong number tinawagan ko. ??? will have to stick with generic ones.
anyway, will go on ahead with my next gc. will be making use of lm1875s using rod elliots schematic. thanks again!
The capacitor comment is basically with the famous LM amps. It has been tested that higher value capacitor swamps the treble portion of the sound, while the low value one will make poor bass performance or low output power capability than expected. The GC thread of the diyAudio made a middle compromise by just using 1000 - 1500uF values (black gates for lowest capacitor impedance, followed by FC caps). The challenge is to make a virtual battery that should be able to give you a solid supply of required current and at the same time do not provide the impedance that those bypass capacitors present to the LM amps, just in order to provide you the tonal balance (bass, mid, high) and ample power as designed.
This virtual battery will just require the LM amps a 1uF bypass capacitance and a steady voltage and current supply. It is rather a surprising discovery and not written in the LM amps datasheet.
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the tiny chassis still has lots of space, you could make it 50% smaller.
(http://203.131.66.146:8080/gc5.jpg)
it doesn't get hot too, when i touched the sides where the chips are attached.... it's barely even warm.
okay question lang... what kind of potentiometers are you using here? can I use the ordinary potentiometers for my GC project (opa549)?
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i think thats a stepped attenuator.
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next question... how does it differ from a regular potentiometer?
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next question... how does it differ from a potentiometer?
it differs in a lot of ways. better search for the types sa Google. lower noise, accurate levels etc. are just some of the benefits.
you can always use your "ordinary" pots as long as you have 20K-100K values.
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ahh... okay.
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ahh... okay.
ingat lang sa mga ordinary pots, sometimes hindi sabay umikot yun governor kaya hindi sabay mag-open yun amps mo. ;D medyo prone din sila sa scratches and hum.
my 0.00001 cents. ;D
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could the pots be tested using a multimeter to determine the fault that you mentioned above? Saan nakakabili ng stepped attenuator? and how much does it usually cost?
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jojo,
ever tested shorting speaker outputs of any of your gcs? ive read the datasheets saying that the chips have some sort of internal protection but have you ever tested shorting them? how bout placing fuses on the speaker outputs? ive seen some local amp makers doing this.
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jojo,
ever tested shorting speaker outputs of any of your gcs? ive read the datasheets saying that the chips have some sort of internal protection but have you ever tested shorting them? how bout placing fuses on the speaker outputs? ive seen some local amp makers doing this.
i have not tested shorting my gcs outputs before. many say that fuse on the speakers degrade the sound, i also haven't tested this.
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could the pots be tested using a multimeter to determine the fault that you mentioned above? Saan nakakabili ng stepped attenuator? and how much does it usually cost?
maybe with a tester but it won't be accurate, you must really listen to the pot. the only local distibutor i know sells a DACT stepped attntr for 2.5K.
HTH,
JojoD
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okay question lang... what kind of potentiometers are you using here? can I use the ordinary potentiometers for my GC project (opa549)?
You can make your own step-attenuator like the one Jojo has. This can be done using rotary switch and resistors as voltage deviders.... you can decide on the values wheither is is logarithmic or linear type.
I haven't done this but it is possible in reality.
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seen that during one of my searches... pero grabe ang build, mukhang rarayumahin ako kapag nakatapos ako ng isa... i'm not sure kung merong available rotary switch with that much positions.
jojo - 2.5 T :o grabe ang mahal nuon ha... might as well spend that much on a brand new transformer.
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seen that during one of my searches... pero grabe ang build, mukhang rarayumahin ako kapag nakatapos ako ng isa... i'm not sure kung merong available rotary switch with that much positions.
jojo - 2.5 T :o grabe ang mahal nuon ha... might as well spend that much on a brand new transformer.
Actually 2.5K for a DACT attenuator is already cheap! pero syempre mahal pa rin if you think that you're just going to use for volume control. But you can use a 12 position switch readily available locally. This is what the cheap switch looks like:
(http://www.euronet.nl/~mgw/background/attenuator/photo_s12mn_gk2.jpg)
This site provides a tutorial on how to DIY an attenuator including a free downloable spreadsheet for the resistor values.
http://www.euronet.nl/~mgw/background/attenuator/uk_attenuator_1.html
Or you can try Lorlin Switches available sa Farnell at P108 each (order code: 422-423, 1 pos. 12 steps SHORTING aka make-before-break ). This uses a Lorlin Switch:
(http://www.euronet.nl/~mgw/background/attenuator/photo_s12bn.jpg)
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Guys,
I have tested shorting the speaker outputs of my gainclones. Nakakatakot lang sa umpisa pero no pain no gain kaya sinibukan ko. Wala naman nasira na chips. All went back to business of making good music.
O ayan cousin skeeter, subukan mo na i-short yun gcs mo. >:D :P ;D
Walang sisihan ha.
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hehehe, sige will try once. better it go pfffft now than later. thanks for trying it out just the same. :)
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My gainclone is currently hooked up to my new aaudio speakers, just want to say that they are making beautiful music together O0
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My gainclone is currently hooked up to my new aaudio speakers, just want to say that they are making beautiful music together O0
Ayus! Pics naman dyan! Ahehehe. ;D ;D ;D
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Jojod18: no trace of sibilance when hooked up with speakers, it sounds natural O0
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Jojod18: no trace of sibilance when hooked up with speakers, it sounds natural O0
I wonder why? Maybe National Semi chips really excel in their sonic region. Burr-Brown chips sounds natural too but needs some form of intervention to control the highs. ST chips are the worst I have tried but with a little effort, they can sound very good too.
Cheers on your setup bro!
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I wonder why? Maybe National Semi chips really excel in their sonic region. Burr-Brown chips sounds natural too but needs some form of intervention to control the highs. ST chips are the worst I have tried but with a little effort, they can sound very good too.
Cheers on your setup bro!
as long as you run the chip within its operating limits it sounds good O0 especially if u use easy to drive speakers ;)
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as long as you run the chip within its operating limits it sounds good O0 especially if u use easy to drive speakers ;)
It's true that I maybe pushing this things to their limits at times but I always make sure that they are within their limits, otherwise, kaboom! ;D
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It's true that I maybe pushing this things to their limits at times but I always make sure that they are within their limits, otherwise, kaboom! ;D
Hi has anyone tried a regulated PS for the GC? I'm somewhat intrigued by Carlos of DIYAUDIO who's been singing praises to the virtue of a regulated PS using a schematic he tested. I know using regulators goes against the prevailing thinking about GC PS because of the chips' high PSRR but since it seems easy enough to do and not expensive, am thinking of tyring it out myself. Just a thought.
Hey John nice going with your gainclone! Wish I could hear them myself. The sibilance I had experienced with my first gainclones actually disappeared when I upgraded sources but am glad the speaker route had the same effect for you. By the way, how efficient are those speakers? ;)
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Hi has anyone tried a regulated PS for the GC? I'm somewhat intrigued by Carlos of DIYAUDIO who's been singing praises to the virtue of a regulated PS using a schematic he tested. I know using regulators goes against the prevailing thinking about GC PS because of the chips' high PSRR but since it seems easy enough to do and not expensive, am thinking of tyring it out myself. Just a thought.
Hey John nice going with your gainclone! Wish I could hear them myself. The sibilance I had experienced with my first gainclones actually disappeared when I upgraded sources but am glad the speaker route had the same effect for you. By the way, how efficient are those speakers? ;)
I did tried them regulators. I used 317/337 in a current boosted config and it did wonders. But I think my regulators can't handle the current demand and needs re-design. You should try using regulators, although I find the sound a bit lifeless. Maybe due to my poor regulators. ;D
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Hi has anyone tried a regulated PS for the GC? I'm somewhat intrigued by Carlos of DIYAUDIO who's been singing praises to the virtue of a regulated PS using a schematic he tested. I know using regulators goes against the prevailing thinking about GC PS because of the chips' high PSRR but since it seems easy enough to do and not expensive, am thinking of tyring it out myself. Just a thought.
Hey John nice going with your gainclone! Wish I could hear them myself. The sibilance I had experienced with my first gainclones actually disappeared when I upgraded sources but am glad the speaker route had the same effect for you. By the way, how efficient are those speakers? ;)
hi garp, its 95 dB @ 8 ohms. back to the gainclone using rectifiers like the mur860 does improve the performance, so i guess using a regulated ps may have some benefit, or you can go to the extreme like peter daniel who swears the sound changes depending on the chassis used >:D
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Wow! Those are high sensitivity speakers, gainclones wouldn't have a hard time driving those for sure. ;D
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Hi has anyone tried a regulated PS for the GC? I'm somewhat intrigued by Carlos of DIYAUDIO who's been singing praises to the virtue of a regulated PS using a schematic he tested. I know using regulators goes against the prevailing thinking about GC PS because of the chips' high PSRR but since it seems easy enough to do and not expensive, am thinking of tyring it out myself. Just a thought.
Hey John nice going with your gainclone! Wish I could hear them myself. The sibilance I had experienced with my first gainclones actually disappeared when I upgraded sources but am glad the speaker route had the same effect for you. By the way, how efficient are those speakers? ;)
Garp,
It's not about PSRR issue, it is about voltage regulation at high power output. Designing more than 20W GC amp, using 1000-1500uF to a 3875/3886 wont give you more than 20W of desired sound. You need higher capacitance to sustain bass requirement of instantaneous current supply. However, using higher capacitance, as reported will swamp your mid and high characteristics. The regulated PS will result to stable PS and will not require high caps value that may swamp the mid/hi.
I am currently working on 2 3886 (2x60watts@6R) with shared reg PS, following carlosfm. But will test without the 33uF carlosfm put on his rail, just a 1uF required at the reg output and a pair of 6800uF before reg.
carlosfm is not the only one who implemented the reg PS, and all of them already made a testimony of the improvement especially in the bass area, and at louder volume. But for less than 20W, I think there is no need for the reg PS.
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are any of your gainclones going to make an appearance at the ws audio fair? ive yet to hear a gainclone (actually dito sa pdvd ko unang narinig yang gainclones) and im quite curious about how they sound. im sure there are a lot of other guys who are curious about them too. thanks!
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are any of your gainclones going to make an appearance at the ws audio fair? ive yet to hear a gainclone (actually dito sa pdvd ko unang narinig yang gainclones) and im quite curious about how they sound. im sure there are a lot of other guys who are curious about them too. thanks!
Sayang, out of town ako sa 26-27. Maybe someone will bring a gainclone to the audio fair. ;)
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Garp,
It's not about PSRR issue, it is about voltage regulation at high power output. Designing more than 20W GC amp, using 1000-1500uF to a 3875/3886 wont give you more than 20W of desired sound. You need higher capacitance to sustain bass requirement of instantaneous current supply. However, using higher capacitance, as reported will swamp your mid and high characteristics. The regulated PS will result to stable PS and will not require high caps value that may swamp the mid/hi.
I am currently working on 2 3886 (2x60watts@6R) with shared reg PS, following carlosfm. But will test without the 33uF carlosfm put on his rail, just a 1uF required at the reg output and a pair of 6800uF before reg.
carlosfm is not the only one who implemented the reg PS, and all of them already made a testimony of the improvement especially in the bass area, and at louder volume. But for less than 20W, I think there is no need for the reg PS.
Thanks for the reply. You're right carlosfm wasn't the first one with regulated PS but I believe was Peranders whose schematic carlosfm initially based on. Although Carlosfm is seems to me making all the noise now. ;D It just makes me wonder though about the need (more about optimization than necessity) for regulation for higher than 20W as you say because the 50W Gaincard still used no regulation and 2200uf caps on the rails. But I guess the answer as usual depends on just trying it out myself and see whether I like it or not. Do let us know your results. Good luck.
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are any of your gainclones going to make an appearance at the ws audio fair? ive yet to hear a gainclone (actually dito sa pdvd ko unang narinig yang gainclones) and im quite curious about how they sound. im sure there are a lot of other guys who are curious about them too. thanks!
Sorry OT guys. Hello Voelker. Romy told me that you used to be with us. Sana we met before you left. Now its only Patrick P. and Romy that I can chat with here about audio. But you know Patrick, he's a bit of a high end guy and I'm a DIYer on a shoestring budget ;D so we're not always on the same note, so to speak.
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hi garp, its 95 dB @ 8 ohms. back to the gainclone using rectifiers like the mur860 does improve the performance, so i guess using a regulated ps may have some benefit, or you can go to the extreme like peter daniel who swears the sound changes depending on the chassis used >:D
Wow! :o That's great! Actually I wouldn't know if the mur860 improves the performance because I've always used those (courtesy of ON Semi) so no benchmark.
You know about the chassis thing you're saying? I just had an experience about that recently but I'm not sure if the change in the sound is attributable to what I think. My gainclone monoblocks have a separate PS chassis and the each amp is in a small rectangular cheap casing that's about half the size of a AVR casing. So seeing the Shigakari mounted on a board on a pic I posted here, I tried this at home and screwed the amps onto a separate 3/4 inch wood and transferred the rubber feet from the chassis to underneath the board. Listened to it and my first thought was, where did the bass go? I was disappointed with the sound so I went back to the old setup but I added about half a kilo of sand in a platic bag inside the chassis. And the bass went back and now it seems even tighter and deeper. This all sounds like bull but I really don't have any other explanation for the change in the bass. ??? I'm not sure about anything but what I'm sure of is that there was indeed a change in the depth and tightness of the bass.
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Hi Garp,
One of the things that was explained (not saying i believe it) is the chassis can play a part since it deals with the resonance, the more controlled the resonance is, the better the sound. Or as what 47 labs does is, to go with the flow i.e.: don't fight resonance, work with it.
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Garp,
Nice observations about chassis resonance. Any other experiments regarding that?
JojoD
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regarding that, i plan to add either a metal bar or wood inside the chassis to separate the two amps, at the same time add wood sidings. narra wood is a good bet, mahal kamagong e >:D i'll also change the rubber feet to spikes so it will be heavier :)
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Garp,
Nice observations about chassis resonance. Any other experiments regarding that?
JojoD
Actually yun lang experiment ko:) Actually when I put the sand bag, I didn't have resonance in mind. It was just to make the amps a little heavy because its so lightweight nahihila siya nung cable pag natabig ko yung cable. But I was surprised that it made a difference because the Gaincard is very lightweight and according to Kimura to control resonance (as opposed to eliminate it) you must have very short signal paths. He didn't mention making the chassis heavy though. Huh? All this talk is alient to me of course. ;D
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regarding that, i plan to add either a metal bar or wood inside the chassis to separate the two amps, at the same time add wood sidings. narra wood is a good bet, mahal kamagong e >:D i'll also change the rubber feet to spikes so it will be heavier :)
I really want to try spikes too pero namamahalan ako sa presyo kasi. And I don't want to use a plumber's bob as a substitute! ;D
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I really want to try spikes too pero namamahalan ako sa presyo kasi. And I don't want to use a plumber's bob as a substitute! ;D
ok lang yan para di lang pogi sa sound gainclone natin...pati sa looks >:D
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I really want to try spikes too pero namamahalan ako sa presyo kasi. And I don't want to use a plumber's bob as a substitute! ;D
I have a classmate in college who now has his own machine shop, I mentioned to him that I would like him to make spikes for me. Either stainless or brass, I still haven't made a design/dimension but he said that he can "torno" those spikes. I will check with him again, who knows, it maybe cheaper for a "PinoyDVD spikes group buy"! ;D
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I have a classmate in college who now has his own machine shop, I mentioned to him that I would like him to make spikes for me. Either stainless or brass, I still haven't made a design/dimension but he said that he can "torno" those spikes. I will check with him again, who knows, it maybe cheaper for a "PinoyDVD spikes group buy"! ;D
Kung sasakali count me in the group buy.
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Kung sasakali count me in the group buy.
Sure, liligawan ko mabuti para mura lang tayo singilin. I already know where to get a 1" diameter solid stainless rod, will look for brass rods too. I think it is easier to tap the brass rod for screws.
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Sorry OT guys. Hello Voelker. Romy told me that you used to be with us. Sana we met before you left. Now its only Patrick P. and Romy that I can chat with here about audio. But you know Patrick, he's a bit of a high end guy and I'm a DIYer on a shoestring budget ;D so we're not always on the same note, so to speak.
OT: hey garp! i left back in 2001, the company had problems at that time. im glad its recovered since then and even surprised to hear a lot of familiar faces are re-joining. too bad i wasn't yet in the hobby when i was there, sa ws ko na nga nalaman na si patrick pala eh nasa hobby din (hi-end at that hehe). romy also told me one of the old principals had one of those megabuck HT/audio setups, baka meron pa dyan quiet lang hehe.
im starting to get interested in audio DIY as some good friends in audio are also into DIY. pag nagka-work tayo dyan (dami lucrative postings dyan recently hehe) turuan mo ko hehe.
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Update on regulated psu gc experiment:
Regulator: LM317/MJ15003, LM337/MJ15004 @ +/-38VDC
GC Chip: LM3875 with 1000uf local cap per rail
Preamp: Foreplay tube preamp
Unfortunately, I liked the sound of the minimalist psu more. I noticed that with the reg psu, the mids are somewhat lost? I mean, they don't appear where they should be. The highs are a bit cleaner and clearer this time. But my biggest disappointment was the bass, it was slow, the low end was gone, a bit boomy with rap/disco music too and most of all, it lost it's definition.
I hope someone else can perform this experiment and post their findings.
OTOH, my next step is to use a modified discrete voltage reference and re-design the regulator circuit but will still use the same pass transistor.
Finally, if all else fails, will try a modified version of a capacitance multiplier used on a JLH class A power amp.
Best regards,
JojoD
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Update on regulated psu gc experiment:
Regulator: LM317/MJ15003, LM337/MJ15004 @ +/-38VDC
GC Chip: LM3875 with 1000uf local cap per rail
Preamp: Foreplay tube preamp
Unfortunately, I liked the sound of the minimalist psu more. I noticed that with the reg psu, the mids are somewhat lost? I mean, they don't appear where they should be. The highs are a bit cleaner and clearer this time. But my biggest disappointment was the bass, it was slow, the low end was gone, a bit boomy with rap/disco music too and most of all, it lost it's definition.
I hope someone else can perform this experiment and post their findings.
OTOH, my next step is to use a modified discrete voltage reference and re-design the regulator circuit but will still use the same pass transistor.
Finally, if all else fails, will try a modified version of a capacitance multiplier used on a JLH class A power amp.
Best regards,
JojoD
Hi JojoD. Thanks for the info on the regulated circuit. Maybe you can try Carlosfm's circuit? I'm just really curious too because his initial attempts at regulated psu didn't impress him until he tried to modify Pedja's circuit. Here's the circuit plus his modifications.
(http://users.verat.net/~pedjarogic/audio/gainclone/images/regulated_supply.gif)
C1 and C2 are 47uf
C3 and C4 are 47nf
Only 33uf on the rails
No D1 and D2 but a diode between ADJ and Out.
Will try this as soon as I get free time and will post my findings as well.
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Hi JojoD. Thanks for the info on the regulated circuit. Maybe you can try Carlosfm's circuit? I'm just really curious too because his initial attempts at regulated psu didn't impress him until he tried to modify Pedja's circuit. Here's the circuit plus his modifications.
C1 and C2 are 47uf
C3 and C4 are 47nf
Only 33uf on the rails
No D1 and D2 but a diode between ADJ and Out.
Will try this as soon as I get free time and will post my findings as well.
Hmmnn might try this as well, just need to get apair of lm338T's
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Hi JojoD. Thanks for the info on the regulated circuit. Maybe you can try Carlosfm's circuit? I'm just really curious too because his initial attempts at regulated psu didn't impress him until he tried to modify Pedja's circuit. Here's the circuit plus his modifications.
C1 and C2 are 47uf
C3 and C4 are 47nf
Only 33uf on the rails
No D1 and D2 but a diode between ADJ and Out.
Will try this as soon as I get free time and will post my findings as well.
Garp,
I used power transistors to boost the lm317/337 in my configuration. Let's see what your research shows us....
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Follow up... a more recent experiment has been more successful in using reg psu for gc amps. It uses a shunt regualtor as a voltage reference for the pass transistors. Definitely better than the boosted circuit in terms of sonics!
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The discrete version of the regulator is a winner indeed. Better bass and cleaner highs was my first impressions. Though still experiencing a bit of worry about the regulators heat dissipation at continued high volume use so must replace my regulator's heatsinks with a bigger one (I'm only using a sheet of aluminum :P).
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The discrete version of the regulator is a winner indeed. Better bass and cleaner highs was my first impressions. Though still experiencing a bit of worry about the regulators heat dissipation at continued high volume use so must replace my regulator's heatsinks with a bigger one (I'm only using a sheet of aluminum :P).
you might need the black heatsinks (for power transistors) bought at alexan hehehe ;D
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you might need the black heatsinks (for power transistors) bought at alexan hehehe ;D
I have some of those around, just can't look for them now. Finish pa ibang projects. ;D
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I have some of those around, just can't look for them now. Finish pa ibang projects. ;D
what design did u use? u have schematics??
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John & JojoD,
Any update on your 17 watts Gainclone?? 8)
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John & JojoD,
Any update on your 17 watts Gainclone?? 8)
Hello,
It is actually a 20W GC, initial tests were successful and convincing. Convincing enough to push the research ahead. However, it is in on hold for the moment. :(
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boss tsip...pwede namang ituloy e, i'm just contemplating if we'll use a regulated instead of the planned power supply for this gainclone... :)
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what design did u use? u have schematics??
I have tried 3 kinds of regulators.
1. Boosted 317/337 circuit, didn't like it.
2. LM338 circuit, though my capacitance multiplier was better, it's performance is better than the boosted circuit.
3. A more reliable discrete version using power transistors as pass regulator with an adjustable shunt regulator as voltage reference. This is the best so far (best in the sense that it improved the usual minimalist gc psu), although it's complexity in construction is not for the faint-hearted.
Sorry, no schematics for 1-3, circuit 3's schematic was drawn on a piece of receipt. :(
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boss tsip...pwede namang ituloy e, i'm just contemplating if we'll use a regulated instead of the planned power supply for this gainclone... :)
Wait, I haven't tested that chip on a regulated psu yet. All my research on regulators used an LM3875 chip in a NI mode.
Let's hope that for the added complexity, the performance gain is big enough.
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(http://gainclone.com/phpBB2/files/picture_gc.jpg)
jfet buffered and regulated gc...looks nice 8)
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Hello,
It is actually a 20W GC, initial tests were successful and convincing. Convincing enough to push the research ahead. However, it is in on hold for the moment. :(
sir jojo anong chip ang ginamit mo d2?
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(http://gainclone.com/phpBB2/files/picture_gc.jpg)
jfet buffered and regulated gc...looks nice 8)
;D built that one too. horrific turn-on thump though :-*
Oh well, Pedja has a lot of solutions in there anyway. ;)
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sir jojo anong chip ang ginamit mo d2?
sir, LM1875 po.
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well di na ito minimalist... :)
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well di na ito minimalist... :)
it's jfet buffered and lot's of other parts so no minimalist gc here. ;D
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A VTL "Integrator" coupled to a NIGC is a pleasure experience indeed. ;)
(http://img23.photobucket.com/albums/v70/jojod818/Dump/Integrator.jpg)
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A VTL "Integrator" coupled to a NIGC is a pleasure experience indeed. ;)
hehe wait for an NIGC coupled with a transformer volume control >:D
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Yeah right, I got the chance to hear a Silver Rock on an ss amp before. Wonder what it would sound on a gc. OK, back to the lab asap.... ;D
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mukhang gagawa ng transformer volume control ang isa dyan ha.... >:D
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magandang diy project yan. ;D may rewinder naman ako eh. ;D ;D
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I got hold of an old external scsi HD chassis (sans the HD). It already has a power supply installed (i have yet to test whether this is still functional), anyway the question is... woud 12V be sufficient to power the OPA549 gainclone? and anyone know the voltage out of the standard computer?
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I got hold of an old external scsi HD chassis (sans the HD). It already has a power supply installed (i have yet to test whether this is still functional), anyway the question is... woud 12V be sufficient to power the OPA549 gainclone? and anyone know the voltage out of the standard computer?
Minimum for single supplies is 8V so i guess ok pa yan.
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since the power supply would be 0 to +12 should I wire the 0 volt to the gnd of my circuit?
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since the power supply would be 0 to +12 should I wire the 0 volt to the gnd of my circuit?
what you need is to built a single supply version and then yes, connect the 0 to ground.
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does a single supply mean I remove the capacitors on the negative (-) voltage input of the opamp?
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does a single supply mean I remove the capacitors on the negative (-) voltage input of the opamp?
for better understanding you must download an app note from TI or NS about single supply operation of op-amps.
btw, there are a lot of debates regarding noise from pc psu. if you are not bothered by that then by all means go ahead with your project.
Cheers,
JojoD
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for better understanding you must download an app note from TI or NS about single supply operation of op-amps.
btw, there are a lot of debates regarding noise from pc psu. if you are not bothered by that then by all means go ahead with your project.
Cheers,
JojoD
hmm... basahin ko nga ulit yung app note ??? as for the debate, I also started reading that in diyaudio... kaso medyo technical at nahihirapan akong sundin... If I might be able to get a toroidal transfo i'll probably gut out the case and install that in its place.
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hmm... basahin ko nga ulit yung app note ??? as for the debate, I also started reading that in diyaudio... kaso medyo technical at nahihirapan akong sundin... If I might be able to get a toroidal transfo i'll probably gut out the case and install that in its place.
Hehe, nagawa ko na din yan pc case gc amp. kaso nasa utol ko kaya di ko makuhanan ng pic! pero hindi toroidal trafo nun, EI core lang.
Try mo din yun pc psu for gc, nun ginawa ko yun ok naman tumunog. Kaso TDA1552Q ginamit ko na chip.
Good hunting,
JojoD
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Thanks for the reply. You're right carlosfm wasn't the first one with regulated PS but I believe was Peranders whose schematic carlosfm initially based on. Although Carlosfm is seems to me making all the noise now. ;D It just makes me wonder though about the need (more about optimization than necessity) for regulation for higher than 20W as you say because the 50W Gaincard still used no regulation and 2200uf caps on the rails. But I guess the answer as usual depends on just trying it out myself and see whether I like it or not. Do let us know your results. Good luck.
I completed my NIGC basic config based on the datasheet. However, I just have 1uF tantalum on both rails of the LM3886 (an experiment based on LM338 bypass discussion that a 1uF tantalum is equivalent to 25uF electrolytic, and lower impedance at high frequency) than using 33uF which carlosfm made use of.
I have the LM338 reg output bypass with .22uF tantalum. My rail is 29-0-29. DC offset is 30mV.
Fired it with Wharfedale 8.3. Tried to find issues with the sound, and listen quite lengthily with different materials of Jheena, which we used to test also my beloved 58-Watt plate STK-based SONY TA-AX22 amp (my main music amp).
I will not be poetic about this one, but I have the impression it has better edge than my SONY. The wharfedale is showing its low-end power. I have snubber circuit and Zobel network in the output at this time. However, I do not have the Ci as shown in the datasheet. I want to listen for hours, very good sounding, no noise even if I put my ear on the cloth cover of 8.3 - what a chipamp.
The only big component on the PCB (about 3/4" x 1.5") is the 33uF cap for the Rm. I run it with Yamaha RX-V630 pre-out. Looks like I have the right combination. My yamaha amp sounds like crap compare to the GC using 8.3.
My next attempt is to make the circuit of JoeRas, and check the DC offset and the sound. Then will finalize my decision and make 6 GC amps, which will be connected to my Yamaha 630 pre-outs, and complete the HT/music setup. Recalling my Sansui AU-D607i, and my bulk vintage amp with AMP-IN, and Yamaha vintage AVR-1000, and experimenting on some GC, the GC showed itself to be of better breed than all those I have the chance to test.
Just me.
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Congrats on your experiment. ;D
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any new owners of gainclones? I plan to do some changes in mine >:D
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any new owners of gainclones? I plan to do some changes in mine >:D
Change is good. ;D ;D ;D
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what's the best-sounding chip to use on a gc?
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what's the best-sounding chip to use on a gc?
Sir, hindi mo dapat tinatanong yan unless your ready for the answers. ;)
Are you ready for the truth? Can you handle the truth? ;D ;D ;D
Parang X-Files kasi yan question mo sir. ;D ;D Fish inihaw!
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what's the best-sounding chip to use on a gc?
Masta Akyat,
For transformation na ba GC mo sir?? hybrid?? >:D >:D
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Sir, hindi mo dapat tinatanong yan unless your ready for the answers. ;)
Are you ready for the truth? Can you handle the truth? ;D ;D ;D
Parang X-Files kasi yan question mo sir. ;D ;D Fish inihaw!
sabihin mo na kc tell the truth ;D ;D ;D ;D dami ata nag- aantay
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sabihin mo na kc tell the truth ;D ;D ;D ;D dami ata nag- aantay
Sorry my friend, trade secret. ;)
A simple tip for you... a certain chip can sound very good when properly implemented, and a very good chip can sound awful when improperly used.
Hence, a simple answer to akyat's question is you will need b*lls of steel and lots of research time with just a single chip to find this out. Not to mention research funds. ;)
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Sorry my friend, trade secret. ;)
e di bulong n lang ;)
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e di bulong n lang ;)
yeah right. ;D
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hmmm... Oonga, yun mga gc's na narinig ko iba-iba ang tunog... iba-iba rin ginamit mong topology sa kanila di ba masta joe? dapat yata magkaroon ng separate gainclone shootout to determine the best chip & topology.
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hmmm... Oonga, yun mga gc's na narinig ko iba-iba ang tunog... iba-iba rin ginamit mong topology sa kanila di ba masta joe? dapat yata magkaroon ng separate gainclone shootout to determine the best chip & topology.
OOngiiiiii..................... ;D ;D ;D
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Shootout? Pwede ba sumali???
Hahahahaha....
......sakit talaga ulo ko! #@!@# ang ginaw kasi!
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Akyat,
Regulated PSU powered GC maganda. :P ;D
OT:
Parang magandang avatar ito ah??? Di na ba nababago yun avatar natin?
(http://img.photobucket.com/albums/v70/jojod818/Dump/MCPhono.jpg)
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OT:
Parang magandang avatar ito ah??? Di na ba nababago yun avatar natin?
(http://img.photobucket.com/albums/v70/jojod818/Dump/MCPhono.jpg)
Looks like a parking lot of Resistors and Capacitors!!! ;D
Wonder how this thing sings ??? If it does, babagyo pa kaya? ;D
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Akyat,
Regulated PSU powered GC maganda. :P ;D
oo maganda yan ;D
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oo maganda yan ;D
akyat,
ayan pati si john agree. sooooo what's next? ;D Fish in the river bed sir. ;D
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Looks like a parking lot of Resistors and Capacitors!!! ;D
Wonder how this thing sings ??? If it does, babagyo pa kaya? ;D
OT:
Technically it hasn't been tested, this thing took so much of my time... so much that I forgot it's Thursday.... nearing so many deadlines! :-\
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how do you dispose of your etchant (ferric chloride)? anyone?
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how do you dispose of your etchant (ferric chloride)? anyone?
I don't, I have this "carbouy" container and when it's half filled (about 3 gallons), I send it to my brother who is into chemicals. I tried reviving FeCL before, it works but it's too messy for me, besides it would involve the use of other chemicals.
I heard once that milk can neutralize ferric chloride, I have no idea how much milk though, frankly I'd rather drink the milk. ;D
In some countries, it is a crime to dispose off such chemicals in sewers.
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I don't, I have this "carbouy" container and when it's half filled (about 3 gallons), I send it to my brother who is into chemicals. I tried reviving FeCL before, it works but it's too messy for me, besides it would involve the use of other chemicals.
I heard once that milk can neutralize ferric chloride, I have no idea how much milk though, frankly I'd rather drink the milk. ;D
In some countries, it is a crime to dispose off such chemicals in sewers.
I know, that's why I'm asking here... if i dilute it in enough water would it be safe to dump on our drains without corroding any metal?
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I know, that's why I'm asking here... if i dilute it in enough water would it be safe to dump on our drains without corroding any metal?
It is probably possible to dillute in H2O, especially during this rainy season. Maybe you can kill some mosquito larvae along the way. ;D
I don't think it can corrode any metal anymore when it is mixed in lots of water. My only concern in this procedure is the effect on underground water pockets.
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It is probably possible to dillute in H2O, especially during this rainy season. Maybe you can kill some mosquito larvae along the way. ;D
I don't think it can corrode any metal anymore when it is mixed in lots of water. My only concern in this procedure is the effect on underground water pockets.
si masta jojo, environmentalist pa.... heheheheh ;D ;D ;D
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si masta jojo, environmentalist pa.... heheheheh ;D ;D ;D
hehehe, eco-friendly lang. ;D ;D ;D
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master jojod, kaya ba mag mukhang ganito?
(http://beta.openreef.com:8080/mf/Resources/Images/2916.jpg)
or ganito?
(http://beta.openreef.com:8080/mf/Resources/Images/2942.jpg)
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master jojod, kaya ba mag mukhang ganito?
(http://beta.openreef.com:8080/mf/Resources/Images/2916.jpg)
or ganito?
(http://beta.openreef.com:8080/mf/Resources/Images/2942.jpg)
Dre, i think chassis lang yung ipapagaya dyan kasi yun loob nun yakang yaka na ni master yun. If ever dre na may mahanap ka na makakagawa ng ganyang klaseng chassis. inform mo naman ako dre. Mukhang matutuwa ako pag meron akong ganyan. ;D ;D ;D Ganda nyan. :o
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Pag nakakita ako ng gumagawa nyan eh hindi na DIY yun presyo nun dahil baka mas mahal pa yun chassis kaysa sa total cost ng parts. ;D ;D ;D
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Masta JOJOd,
OO nga very nice design syempre iba din jaform..
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asan ang pics? di ko makita
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starting to build my stereo OPA 549 based para + bridge amp.
(http://groups.msn.com/_Secure/0TwAdA7AWTYF*tH8Hfn2n8y0*t*InKHpBjbfa10smjXfPen4DBiJ3YS0BOMOYkayO4DasxLNNrsGWw2MCyoJBR0FdDKly4cpceb4eEpl3b30nBbbDD3KW0w/close%20up%20opa549.JPG?dc=4675489752998859117)
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for the stereo GC amp
(http://groups.msn.com/_Secure/0UgAdA8YXLddVsEN0gXCTn!R96KaEXjq7Djr2lR7vmhW1*RB8vsirob2SJsPh8EGGQoZeJwdwhJQKgpVJ2sVTJJjJMhBW5G5ck5xIuGBFMAqoUR*U28TFYFDeZrj5L!jJ/para%20bridge%20opa549.JPG?dc=4675489753145280915)
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now for the chassis, finding the right heat sink ;D
(http://groups.msn.com/_Secure/0TwARA0kXjaSAnYqbHrozM31KXoTaomBXRGO92Tdxn1qbAnIZUcvgA2AfXV5gxGup*8UeWD4sQstkr1dVTyJ!r7LG4S9rLp4ZRbU8x6z0ZqdK7M27ve!fpg/heat%20sink%20whole.JPG?dc=4675489753310837588)
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heat sink cut. bigger half for the stereo amp. the other one for my next sub woofer GC based plate amp.
(http://groups.msn.com/_Secure/0TgARA9wWuYSAnYqbHrozM31KXoTaomBXxEoKTIJ3AAdIJ!eHdrTeTStjZakJTblZa9GL9iUQ2DSfO1nPMLwoVrR1plyuz9fmtbBCFU2fdOw8MHgISf3z8w/heat%20sink%20open.JPG?dc=4675489753420104738)
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front
(http://groups.msn.com/_Secure/0SwAdA2MWk1pfz5kYscXczusf9yNJvq3fB6WTa*366x2WboPjbBXKucc!9j47Pl5c66FdFJ9nT9OItqN1e6sQyKvuh4fVO5gUJtSPRmfINTdnvrPeezsn5w/front%20chassis.JPG?dc=4675489753510007947)
back
(http://groups.msn.com/_Secure/0UgDrAj0YkvF7sk3y2VS!1!qWBDVbTI2aVVZwJW64zw1oqz6WnXyPlbagGvy9!zvja2m2jf*zG82kwEA22E749M2!btfztooEafFsPmDpRbxEXVRnsGkCT6en9dvrif62/back%20view%20chassis0.JPG?dc=4675489757131869559)
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now for the chassis, finding the right heat sink ;D
(http://groups.msn.com/_Secure/0TwARA0kXjaSAnYqbHrozM31KXoTaomBXRGO92Tdxn1qbAnIZUcvgA2AfXV5gxGup*8UeWD4sQstkr1dVTyJ!r7LG4S9rLp4ZRbU8x6z0ZqdK7M27ve!fpg/heat%20sink%20whole.JPG?dc=4675489753310837588)
Sir, where do you souce your heat sink? I need those type of heat sink on my new gain clone - 6 channels.
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Galing-galing naman rmpmla! Congrats on your new baby! ;)
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Sir, where do you souce your heat sink? I need those type of heat sink on my new gain clone - 6 channels.
bought it from a surplus equipment warehouse in Raymundo Ave.,Pasig. This heat sink came from a strip down Inverter drive. Natyempohan ko lang :). I don't know if its cheap but paid 1K kasi P130 daw per kilo ng aluminum and it weighs around 7kg.
will PM u how to get there.
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Galing-galing naman rmpmla! Congrats on your new baby! ;)
Jojo, thanks. visually, mukhang maganda nga ang end result. problema ko na lang e kung gagana ;D
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Jojo, thanks. visually, mukhang maganda nga ang end result. problema ko na lang e kung gagana ;D
im sure it will. ;) ikaw pa.
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im sure it will. ;) ikaw pa.
:) :) :)
will post result once i finished this one.
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bought it from a surplus equipment warehouse in Raymundo Ave.,Pasig. This heat sink came from a strip down Inverter drive. Natyempohan ko lang :). I don't know if its cheap but paid 1K kasi P130 daw per kilo ng aluminum and it weighs around 7kg.
will PM u how to get there.
Thanks for the help sir!
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aHobbit,
I once saw this heatsinks in Sta. Cruz Manila, and yes rmpmla is right, they are sold by weight. ;D Will check this friday if it is still available.
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Sir, directions naman.
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Sir, directions naman.
Sa may malapit sa Akihabara yun dati ko nakita, since pupunta ako this thursday to buy parts and stuff, I will look for it and take note the store's name.
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aHobbit,
It is unfortunate na wala na yun mga heatsinks na per kilo! Puro mga standard types na lang ang meron sir. Sorry. :(
JojoD
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I'm newbie in this thread. Can anybody give a training or seminar regarding gainclones DIY. I think, all of us reading this thread are interested. ;D
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you can ask the master of DIY JojoD ;D kami kasi nagpapagawa na lang ;D
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I'm newbie in this thread. Can anybody give a training or seminar regarding gainclones DIY. I think, all of us reading this thread are interested. ;D
You could check out this site: http://www.decdun.fsnet.co.uk/gainclone.html
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I'm newbie in this thread. Can anybody give a training or seminar regarding gainclones DIY. I think, all of us reading this thread are interested. ;D
Tell me what you're capable of and I'll show you how. ;) I ask this because you need to know some basic electronics and of course, some soldering skills.
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You could check out this site: http://www.decdun.fsnet.co.uk/gainclone.html
Isn't that Nuuk's webpage?
;D Another DIY GC serial builder! ;D
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bought it from a surplus equipment warehouse in Raymundo Ave.,Pasig. This heat sink came from a strip down Inverter drive. Natyempohan ko lang :). I don't know if its cheap but paid 1K kasi P130 daw per kilo ng aluminum and it weighs around 7kg.
will PM u how to get there.
Sir rmpmla, waiting for your PM! thanks
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Isn't that Nuuk's webpage?
;D Another DIY GC serial builder! ;D
yup :)
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Sir rmpmla, waiting for your PM! thanks
you got PM :)
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Flash update for all NIGC users:
Try the T-network mod for the NIGC, and you'll like it for sure! I did! AWESOME. :o
I still have a lot of pencil pushing left for the theoretical input impedance of 22K and the amp is not in a picture ready position now but it sings.
I hope to hear comments from those who will try this "innovation" as they say.
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Uy! new sounding mod..... am sure maganda yan ;) try nyo....
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Flash update for all NIGC users:
Try the T-network mod for the NIGC, and you'll like it for sure! I did! AWESOME. :o
I still have a lot of pencil pushing left for the theoretical input impedance of 22K and the amp is not in a picture ready position now but it sings.
I hope to hear comments from those who will try this "innovation" as they say.
From the other forum, the T-network has really not much benefit for the NIGC since typically, you can use low-value R in the feedback ckt independent of the amps' input impedance. It is a substantial mod for the IGC since the input impedance of an IGC amp is part of the feedback circuit. Maintaining typical input impedance for a typical power amp (at 10k~22k) may somewhat be tolerable (use of 500k~1.1m R for the max gain of 50). But having an input impedance of 47k (typical of integrated amp) the use of feedback R is already a pain in the noise floor. Thus, the T-network lets you enjoy the LM GC in an inverted config without (probably) a need for a buffer stage.
The findings are all documented with IGC and yes, it is a very good mod for those with LM in their GCs. My blueprint for my final 6-channel have this mods already. A fixed value, though, has been recommended in the diyaudio forum, and has been tested. This is because, computing the value maybe easy, but the complication of each value to the overall amp ckt (especially the output offset DC voltage) is somehow hard to be appreciated.
The value is 10k 100 10k in the T configuration as feedback R. 10k to the ground from the NI input. This value is for amp with 22k input impedance. As such, this amp config will need buffer before it.
Sometimes, I have the urge to just request the assistance of Mr. JojoD for this frequent improvement on the LM GC because I dont have the luxury of time. ;D Though it is not really a waste of effort if you happen to hear one really sounding good!
Spending small money and time for something being sold by others at thousands of dollars is somehow a motivation.
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From the other forum, the T-network has really not much benefit for the NIGC since typically, you can use low-value R in the feedback ckt independent of the amps' input impedance. It is a substantial mod for the IGC since the input impedance of an IGC amp is part of the feedback circuit. Maintaining typical input impedance for a typical power amp (at 10k~22k) may somewhat be tolerable (use of 500k~1.1m R for the max gain of 50). But having an input impedance of 47k (typical of integrated amp) the use of feedback R is already a pain in the noise floor. Thus, the T-network lets you enjoy the LM GC in an inverted config without (probably) a need for a buffer stage.
The findings are all documented with IGC and yes, it is a very good mod for those with LM in their GCs. My blueprint for my final 6-channel have this mods already. A fixed value, though, has been recommended in the diyaudio forum, and has been tested. This is because, computing the value maybe easy, but the complication of each value to the overall amp ckt (especially the output offset DC voltage) is somehow hard to be appreciated.
The value is 10k 100 10k in the T configuration as feedback R. 10k to the ground from the NI input. This value is for amp with 22k input impedance. As such, this amp config will need buffer before it.
Sometimes, I have the urge to just request the assistance of Mr. JojoD for this frequent improvement on the LM GC because I dont have the luxury of time. ;D Though it is not really a waste of effort if you happen to hear one really sounding good!
Spending small money and time for something being sold by others at thousands of dollars is somehow a motivation.
I share your enthusiasm in this mod, in fact I already have several specimens for the t-network experiment. I patterned my test setups with the ones done by Joe Rasmussen in his experiments. My initial findings were consistent becasue I also monitored a huge jump in dc offsets from a mere 2mV to a whooping 68mV. Not good as he says, but the point of tinkering will be at the +VE resistor to ground that has a much more effect on dc offset due to the removal of the bypass cap. After replacing a trimmer in place of the +VE resistor, I found that the best value for my particular feedback resistor values would be 10K5 ohms. With that value, the output offset settled at 2.5mV, a huge benefit considering the use of T-networks.
I still believe that the NIGC "still" needs a buffer even if the T-network is used because the chips gain is still affected with the pots setting, one solution to relieve the buffer is to use a stepped attenuator that would represent a constant impedance with respect to the chip.
Hay naku, 3 days na ako nagsusunog ng kilay dito sa research na ito, it's very promising and I believe worth the man hours spent. I'll keep you guys posted of my findings as soon I can replicate them and have them standardized. ;)
JojoD
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I still believe that the NIGC "still" needs a buffer even if the T-network is used because the chips gain is still affected with the pots setting, one solution to relieve the buffer is to use a stepped attenuator that would represent a constant impedance with respect to the chip.
JojoD
I may not understand for now how the pots will affect the NIGC gain. Anyway, I am not one of those that prefer the LM GC w/o the buffer. ;D
Now you know why I am still keeping my RX-V630. ;)
It's my Pre/Pro :o. Its amp is basically for my kids, connected to a good-looking 5-piece tweaked Sakura wood cube speakers. :D - bought it with a sub box and 6-ch sakura amp for 2.5k last Christmas. :o This Sakura amp will be modified to implant the 6-ch OPA549 GC (samples) ;D using the Sakura built-in pre-amp/buffer. The circuit board of this Sakura amp is quite straight forward - modifying is fairly simple.
Remember, if it is working, tweaked it! ;)
It seems these exercises never ends.
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Good luck on your project! Indeed this exercise never ends, it only gets better and better.
;D
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I may not understand for now how the pots will affect the NIGC gain. Anyway, I am not one of those that prefer the LM GC w/o the buffer. ;D
Now you know why I am still keeping my RX-V630. ;)
It's my Pre/Pro :o. Its amp is basically for my kids, connected to a good-looking 5-piece tweaked Sakura wood cube speakers. :D - bought it with a sub box and 6-ch sakura amp for 2.5k last Christmas. :o This Sakura amp will be modified to implant the 6-ch OPA549 GC (samples) ;D using the Sakura built-in pre-amp/buffer. The circuit board of this Sakura amp is quite straight forward - modifying is fairly simple.
Remember, if it is working, tweaked it! ;)
It seems these exercises never ends.
sir, can you tweak the sakura amp? im planning to buy a Sakura 387 paired with wharf 8.1 and WH2 center and rear. if ever you can tweak it, anong added performance ang puwedeng madadagdag?
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sir, can you tweak the sakura amp? im planning to buy a Sakura 387 paired with wharf 8.1 and WH2 center and rear. if ever you can tweak it, anong added performance ang puwedeng madadagdag?
HI markgail,
Yung speaker lang na tweak ko.
Yung amp hindi tweak ang gagawin ko, ooperahan ko talaga - I will do a medical process of AMP TRANSPLANT ;D.
Understand that my sakura amp I have is fairly low power that made use of TIP transistors to 5 channels - so they can pack 6-channels into it but sounds so-so. But it has big 24-0-24 trafo (torroids) and useful heatsink :o. From TIP to OPA549, it would be a jump in performance though there are technical issues I have to solve first (e.g. rail vltage as OPA549 has lower rail V requirement). Sa LM, swak na swak yung torroid supplied, and will better OPA549 (IMO, baka ulanin ako ng missile ng OPA549 fans club ;D).
With other Sakura, I can not comment on it. Sorry. :-[
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Good luck on your project! Indeed this exercise never ends, it only gets better and better.
;D
;D
I got hooked on this! The amp circuit I have is so tiny, and yet the sound good - better than all discrete amp I ever have. and when new tweak is published, I really cant resist the urge to implement it, especially when the proponents show discrete measurements on the improvement. But it did stop me from looking somewhere else for better amp.
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sa LM, swak na swak yung torroid supplied, and will better OPA549 (IMO, baka ulanin ako ng missile ng OPA549 fans club ;D).
With other Sakura, I can not comment on it. Sorry. :-[
dont worry, Patriot missiles are up and ready to intercept incoming missiles. ;D ;D ;D
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;D
I got hooked on this! The amp circuit I have is so tiny, and yet the sound good - better than all discrete amp I ever have. and when new tweak is published, I really cant resist the urge to implement it, especially when the proponents show discrete measurements on the improvement. But it did stop me from looking somewhere else for better amp.
As for the toroid, your idea to use LM chips is a good choice but if the chassis has room, you can regulate your psu for a +/-30V supply! Kaso masyado matrabaho yan! Hahahaha ;D
Pero that's what we're here for dba, the hours of designing, drilling, soldering etc. Plus enjoying the many hours of good listening! ;D ;D
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As for the toroid, your idea to use LM chips is a good choice but if the chassis has room, you can regulate your psu for a +/-30V supply! Kaso masyado matrabaho yan! Hahahaha ;D
Pero that's what we're here for dba, the hours of designing, drilling, soldering etc. Plus enjoying the many hours of good listening! ;D ;D
On designing, I made another shortcut.
Bought Pioneer SA-8800 integrated amp with Pre-out and PowerAmp-in yesterday. :). Solid chassis, 5mm aluminum faceplate, solid aluminum knobs, 9 heavy-duty switches, RCA jack, outlets, etc etc.
1k lang :o
Defective daw :-X
The amp has burned resistor. hmmn. I cut the rail voltage to the amp to prevent further damage. ???
I tested the pre-amp, its working! ;D
A Pioneer SA-8800 preamp with 2 phono pre/input for 1k, not bad. :D
So back in the design. I will house my 6-ch GC here. ;D The pioneer circuit board will now have to retire.
All RCA, knobs, outlets, trafo & mounting, with good hi-gauge chassis, heatsink, 2 ELNA 10k caps and elegant (but non-functional) look of the SA8800 are all in place - can i buy same quality material and layout from RAON for 1k? 8)
My problem: Sayang pre-amp, working! pwede siguro ibenta! ;D mga 1k para libre na chassis ko!!! ;D
ubos oras na naman!!! ;D
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ang lupit niyo mga bossing. dami niyong alam sa electronics.
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front
(http://groups.msn.com/_Secure/0SwAdA2MWk1pfz5kYscXczusf9yNJvq3fB6WTa*366x2WboPjbBXKucc!9j47Pl5c66FdFJ9nT9OItqN1e6sQyKvuh4fVO5gUJtSPRmfINTdnvrPeezsn5w/front%20chassis.JPG?dc=4675489753510007947)
back
(http://groups.msn.com/_Secure/0UgDrAj0YkvF7sk3y2VS!1!qWBDVbTI2aVVZwJW64zw1oqz6WnXyPlbagGvy9!zvja2m2jf*zG82kwEA22E749M2!btfztooEafFsPmDpRbxEXVRnsGkCT6en9dvrif62/back%20view%20chassis0.JPG?dc=4675489757131869559)
update :)
(http://groups.msn.com/_Secure/0QQCLGfkSSGhd139MxRoLLJvNCdlTcha2f6*vmycfvbJy8DAUqDEkcZuIAnAOSWz!ckow9tZhndMybXLm8ayO2tjldqFbovcNsXky*KGpFZU/front.JPG?dc=4675493610068012947)
(http://groups.msn.com/_Secure/0PwAAACMSCzNgzIjLgekpSVNpC4oxhQP*s18P6uMcsgPJBo7Xm5D3qM*6*ZZV1o2oWYNzp4gVn*GDlROcUGDjOT01hr*xwctA/top.JPG?dc=4675493610562136209)
(http://groups.msn.com/_Secure/0QACNAmESzUK3yNiOLb8NCkGh2x3RCMQd0pG0P06ZG4MHt7kV5o*23IfFeVnGJtDwSh68t3B3gcAc9F3aMH2c9P9LYLFmv8MBzoyNAgBw3hc/back.JPG?dc=4675493611706426847)
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update :)
(http://groups.msn.com/_Secure/0QQCLGfkSSGhd139MxRoLLJvNCdlTcha2f6*vmycfvbJy8DAUqDEkcZuIAnAOSWz!ckow9tZhndMybXLm8ayO2tjldqFbovcNsXky*KGpFZU/front.JPG?dc=4675493610068012947)
(http://groups.msn.com/_Secure/0PwAAACMSCzNgzIjLgekpSVNpC4oxhQP*s18P6uMcsgPJBo7Xm5D3qM*6*ZZV1o2oWYNzp4gVn*GDlROcUGDjOT01hr*xwctA/top.JPG?dc=4675493610562136209)
(http://groups.msn.com/_Secure/0QACNAmESzUK3yNiOLb8NCkGh2x3RCMQd0pG0P06ZG4MHt7kV5o*23IfFeVnGJtDwSh68t3B3gcAc9F3aMH2c9P9LYLFmv8MBzoyNAgBw3hc/back.JPG?dc=4675493611706426847)
Kaganda talaga ng heatsink mo!
How much did you score your OPA549, saka saan mo ini-score?
Care to share your schematics and parts - or at least the URL source?
Give us the impression on the sound.
Congrats on a very beautiful work of art! 8)
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Wowow, ang bangis! ;D ;D ;D Nice work sir!
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Kaganda talaga ng heatsink mo!
How much did you score your OPA549, saka saan mo ini-score?
Care to share your schematics and parts - or at least the URL source?
Give us the impression on the sound.
Congrats on a very beautiful work of art! 8)
aHobbit, thanks :)
The OPA's are just samples from TI. try mo lang mag sample request and they will deliver it by UPS. have seen this OPA549 on RS components catalog, and if i'm not mistaken, the price is about P2,500 each ;D
ito ang pinagkopyahan ko nung amp schematics
http://www.freewebs.com/matttcatttweb/audio.htm
as for the parts, its a mixture of cheap new parts from Raon, and some surplus/used parts like the heat sink, caps, and PS switch with noise filter.
Right now, i have to do some troubleshooting kasi may faint motor boating sound ( this distortion is fixed, meaning it does not increase as u turn the volume up ). first time ko na ma-encounter ???
but once there is input source and u turn up d volume, hindi mo na ma-notice yung distortion. A very powerful Amp though. it can drive my Bose 901 with ease.
my impression ???, with the gainclones i built, OPA549 sounds better than OPA541 and TDA 7294( used by nohr's le amp ). the OPA 549 para+bridge amp just have extra power ;D
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Wowow, ang bangis! ;D ;D ;D Nice work sir!
sir Jojo, thanks :) :)
sarap sana kung unang power up ay walang problema ;D. Now have to find a way to reduce or eliminaye the distortion (motor boating sound) ???
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The OPA's are just samples from TI. try mo lang mag sample request and they will deliver it by UPS. have seen this OPA549 on RS components catalog, and if i'm not mistaken, the price is about P2,500 each ;D
Thanks for the info. Do you mean you scored the eight 549 just by sample? I thought up to 5 lang yon?
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Thanks for the info. Do you mean you scored the eight 549 just by sample? I thought up to 5 lang yon?
You are right. For the 549 and 541 hanggang 5 ang pwede i-request. but there are different types kaya makakarami ka. meron na 549S at 549T ;D sa 541 tatlong klase yata
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sir Jojo, thanks :) :)
sarap sana kung unang power up ay walang problema ;D. Now have to find a way to reduce or eliminaye the distortion (motor boating sound) ???
that's the challenge sir, it is possible that it can be coming from grounding problems. usually my grounds are so messed up too but i never had a hum/motorboat problem before.
you mentioned that when no input is connected there is hum, is the back panel made of metal?
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that's the challenge sir, it is possible that it can be coming from grounding problems. usually my grounds are so messed up too but i never had a hum/motorboat problem before.
you mentioned that when no input is connected there is hum, is the back panel made of metal?
korek ka dyan sir, consolation ko na lang dito eh tumutunog siya ;D. maramirami na rin yung pinausok ko na chip amp eh ;D
thanks for the hint :) , will check grounding of my amp this weekend. m also suspecting problem with power supply, baka dun nangaling yung hum/motorboat sound
the panel is made of acrylic plastic.
sir the hum has a fixed volume, it does not increase even if you turn the volume control of the amp to maximum (with input source at pause/stop)
again, Jojo, thanks for the help.
Butch
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rmpmla,
did you separate your signal ground and power ground? the power ground carries a huge amount of current that can be modulated to your input through the signal ground and cause a steady hum, and your probably right, it is in the psu.
good luck,
JojoD
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rmpmla,
did you separate your signal ground and power ground? the power ground carries a huge amount of current that can be modulated to your input through the signal ground and cause a steady hum, and your probably right, it is in the psu.
good luck,
JojoD
Is there a simple way to fix the SIGNAL or POWER grounds to eliminate or decrease the humming sirs? ::) thnks
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rmpmla,
did you separate your signal ground and power ground?
good luck,
JojoD
that i have to check. the signal ground goes to the DRV134. i might have terminated the ground pin to the power ground that's why there is a steady hum.
thanks,
Butch
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good luck, hope you find it and congrats on your new amp! ;)
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rmpmla
Hope you fix it.
Congrats on your amp.
Mga sir, nawala po ako sa circulation for awhile my computer bug down and recently landed a job.
Sir jojo
nasa akin pa rin yung LM12 na IC, hope to see you sa EB.
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rmpmla
Hope you fix it.
Congrats on your amp.
Mga sir, nawala po ako sa circulation for awhile my computer bug down and recently landed a job.
Sir jojo
nasa akin pa rin yung LM12 na IC, hope to see you sa EB.
FASTBACK,
Congrats on your new job and welcome back bro! Hope to see you too in the EB.
Thanks,
JojoD
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Mga sir, nawala po ako sa circulation for awhile my computer bug down and recently landed a job.
FASTBACK,
welcome back and congrats on your new job! :)
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JojoD and rmpmla
Thanks
Sure I'll be there sa grand EB so hope to see you there.
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has anyone tried using the t network for gainclone? thats what im doin now.i just want to ask your opinion about it.
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has anyone tried using the t network for gainclone? thats what im doin now.i just want to ask your opinion about it.
try it, you'll either hate it or love it. ;D
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moonshow,
donot use a 10k resistor as dummy load, the nearest value you can buy is 8.2 ohms and about 10 watts.
just replace the 10k resistor from NI input to ground with a trimmer and set it to 10K, then after power up, measure your output dc offset and then adjust your trimmer accordingly. when you're satisfied with your offset, power down and remove the trimmer and measure it's resistance, then buy a resistor as close as possible to the measured resistance you had in your trimmer. HTH
remember, safety first!!!
goodluck and godspeed!
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Oh Garp, yohoo....
LM4780 R&D has begun, armed with a magnifying lens, i never expected the pins to be so closed together. >:( ;D Hope it works. ;D
Exciting!
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has anyone tried using the t network for gainclone? thats what im doin now.i just want to ask your opinion about it.
When I saw the osciloscope display of the T-netd IGC noise floor against the non-T-netd IGC of same gain, I am convinced of the benefit of the mod. I have finished the T-net board for my GC but lacks time to mount it at the moment on my operational GC (NIGC). Have to finish 6 channels, have all materials avbl with me, and assembly is still to be sked.
if you are using the 10k-100R-10k T-net values, a DIY person posted that you use 7.5k on the NI pin to put down the DC offset to less than 20mV.
Fot NIGC, the T-net has some unwanted surprising effects - on the DC offset. I am building 6-channel IGC. I am currently using NIGC in my main system. I will recommend that you go ahead with it and your efforts will be rewarded with a much better GC performance.
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Oh Garp, yohoo....
LM4780 R&D has begun, armed with a magnifying lens, i never expected the pins to be so closed together. >:( ;D Hope it works. ;D
Exciting!
Magkano kuha mo LM4780 saka saan?
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Magkano kuha mo LM4780 saka saan?
It's from Garp and he gave it to me for testing. ;D Still no local sources for this one. :(
The pins are so tightly spaced! Duh! >:( Pero there is no stopping us this time. >:D Ang kinakatakot ko lang once finished na ito, cross-eyed na ako! ;D ;D
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When I saw the osciloscope display of the T-netd IGC noise floor against the non-T-netd IGC of same gain, I am convinced of the benefit of the mod. I have finished the T-net board for my GC but lacks time to mount it at the moment on my operational GC (NIGC). Have to finish 6 channels, have all materials avbl with me, and assembly is still to be sked.
if you are using the 10k-100R-10k T-net values, a DIY person posted that you use 7.5k on the NI pin to put down the DC offset to less than 20mV.
Fot NIGC, the T-net has some unwanted surprising effects - on the DC offset. I am building 6-channel IGC. I am currently using NIGC in my main system. I will recommend that you go ahead with it and your efforts will be rewarded with a much better GC performance.
Exactly why I was suggesting a 20K trimmer so he can trim the dc offset and find the best value of NI resistor. ;D
Two months ago when I first built a t-netd gc it was a pain in the a$$ due to offset, nevertheless, there are ways to tackle this for the benefits are woth it. My own hybrid gc is now t-netd for the same reasons. :)
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so the trimmer resistor really varies from system to system?
that diy guy you are reffering to, i think is nick whetstone or nuuk.
im using his schematic.
jo, should i get the trimmer pot already? or should i try my 10k and 6k8 resistors first?
what do you mean by 10 watts?
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so the trimmer resistor really varies from system to system?
that diy guy you are reffering to, i think is nick whetstone or nuuk.
im using his schematic.
jo, should i get the trimmer pot already? or should i try my 10k and 6k8 resistors first?
what do you mean by 10 watts?
you got it wrong my friend, the trimmer (or 10K) varies from chip batches not from anyone's system.
the dummy load resistor your asking must be 5 watts or higher so get 10 watts.
if your pertaining to Nuuk's circuit, then he also used a trimmer to arrive at his values for the resistor on the NI to ground.
to make things clear, the trimmer is there just so you can trim the dc offset, then you'll remove it and replace it with a fixed resistor according to the value of the trimmer after adjustment. HTH
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another technique is to just use a 20K trimmer (highest quality you can find) for the 10K resistor at the NI to ground.
oh, if you worry too much about making any mistake, buy an LM1875 (smaller brother of the LM3875) which is around P90 only and practice your t-network there, at least, if you see any magic smoke, it'll just be your P99 chip. ;D ;D ;D ;D
you can use the same circuit as the 3875 except for the psu that must be max of +/-30V. ;)
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i think ill do that.sayang un chips medyo mahirap maghanap.
just to clarify, the ni to ground resistor i would use that has the value derived from the trimmer pot would be 10 watts,instead of the normal .5-1 watt resistors i use?
one more question, the wiring for the lm3876 chip is exactly the same as the lm3875 in the t netwrok inverted gainclone schematic right?disregarding the mute pin.
mang tony gave me the wrong chips, called him up.hes now in russia. so have to do with the 3876s
thanks for all the help
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i think ill do that.sayang un chips medyo mahirap maghanap.
just to clarify, the ni to ground resistor i would use that has the value derived from the trimmer pot would be 10 watts,instead of the normal .5-1 watt resistors i use?
one more question, the wiring for the lm3876 chip is exactly the same as the lm3875 in the t netwrok inverted gainclone schematic right?disregarding the mute pin.
mang tony gave me the wrong chips, called him up.hes now in russia. so have to do with the 3876s
thanks for all the help
yikes! the 10 Watts is for your dummy load resistor (what you connect to the output when testing). This is what you'll use if you don't have a cheap speaker for testing.
regarding the 3876, yes it is ok to use the circuit of the 3875. But be careful about the mute pin! If not attended properly, this may cause the chip to mute during normal operation. This is exactly the reason why we refrain from using it, but it can be retro-fit to do just like a 3875. Just check the datasheet of the 3876 to be 100% sure. ;)
now this may seem to complicate your life a little bit, but it would be better that you know about the mute pin before you start your project.
btw, if you have sensitive speakers, you'll love the 1875, it's a bit more tubey sounding. ;D
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life o life!
hehe, anyone knows where to buy lm3875s?
lm1875's max power is probably only half the 3875s right?
i find it a bit low powered...
how does the ti chips compare to the lm's ?
i might just use the ti chips.......
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life o life!
hehe, anyone knows where to buy lm3875s?
lm1875's max power is probably only half the 3875s right?
i find it a bit low powered...
how does the ti chips compare to the lm's ?
i might just use the ti chips.......
as of the latest (according to boy raon ;D) no local shops carry the 3875. eh di isang channel lang muna yun 1875, parang research amp lang naman eh, para di mabigat sa bulsa pag may magic smoke. ;D Besides, kung high sensitivity speaker mo, oks na din. Wag lang mag-party sa inyo. ;D
as for the TI chips, matagal na ako wala balita dyan. :(
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hehe, i'll try the 1875 first.
cno meron spare na lm385?kahit isa lang? ill buy it!
un isa lang nasira,i still have the other one intact sayang naman.
and,who want to buy unused 3876s? i have 2 here. :)
jo,theoretically ilan watts un lm1875 and will all my purchased parts for the 3875 work for the 1975?
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hehe, i'll try the 1875 first.
cno meron spare na lm385?kahit isa lang? ill buy it!
un isa lang nasira,i still have the other one intact sayang naman.
and,who want to buy unused 3876s? i have 2 here. :)
jo,theoretically ilan watts un lm1875 and will all my purchased parts for the 3875 work for the 1975?
1875 is around 20W but for lower THD you can rig it for a max output of 15W.
bili ka na lang ulit ng parts para may reserve parts ka na for the big one. ;D Barya lang sayo yan. ;)
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another technique is to just use a 20K trimmer (highest quality you can find) for the 10K resistor at the NI to ground.
oh, if you worry too much about making any mistake, buy an LM1875 (smaller brother of the LM3875) which is around P90 only and practice your t-network there, at least, if you see any magic smoke, it'll just be your P99 chip. ;D ;D ;D ;D
you can use the same circuit as the 3875 except for the psu that must be max of +/-30V. ;)
Am still at a loss where to get this chip at this price? HELP!!!
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Am still at a loss where to get this chip at this price? HELP!!!
;D ;D The 1875 is all over RAON, price ranges are P90-110 only. ;) Even Deeco has em.
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(http://img.photobucket.com/albums/v70/jojod818/OPA549T_Buffered/OPA549T_Buffered0000.jpg)
Thought I share this with you guys, my wood amp GC was attacked by several unknown pests, it seems they loved chewing the wires. >:( My friends were so happy because finally I am going to rebuild it in a chassis. ::)
I really need to get a cat. ;D
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Rebuild! Rebuild! Rebuild! ;D
(http://img.photobucket.com/albums/v70/jojod818/OPA549T_Buffered/GCIAB_01.jpg)
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A friend gave me the big ELNA caps, why not use it? ;D
(http://img.photobucket.com/albums/v70/jojod818/OPA549T_Buffered/GCIAB_02.jpg)
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Installing these things needs some practice indeed!
(http://img.photobucket.com/albums/v70/jojod818/OPA549T_Buffered/GCIAB_03.jpg)
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Wiring in tight places can be a real pain, burns from the soldering iron are inevitable. ;D I used OFC for the psu wiring, and silver for IC and speakers, hope it turns out good. ;D
(http://img.photobucket.com/albums/v70/jojod818/OPA549T_Buffered/GCIAB_04.jpg)
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WOW!!! another great sounding machine ito Masta Jojo..... saan setup naman kaya ito........ baka sa banyo ;D ;D ;D
Hope to hear it soon ;)
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WOW!!! another great sounding machine ito Masta Jojo..... saan setup naman kaya ito........ baka sa banyo ;D ;D ;D
Hope to hear it soon ;)
You will hear it soon. ;D Pero this time I'll make sure na hindi na aabutin ng mga bubwit. ;D May chassis na at may pusa na kami! ;D
Finished!
(http://img.photobucket.com/albums/v70/jojod818/OPA549T_Buffered/GCIAB_05.jpg)
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Front view, wala ako mahagilap na knob, pahiram muna ha.... ;D ;D ;D
(http://img.photobucket.com/albums/v70/jojod818/OPA549T_Buffered/GCIAB_06.jpg)
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Parang mas maganda tignan yun likod, madami ginto. ;D ;D ;D
(http://img.photobucket.com/albums/v70/jojod818/OPA549T_Buffered/GCIAB_07.jpg)
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You will hear it soon. ;D Pero this time I'll make sure na hindi na aabutin ng mga bubwit. ;D May chassis na at may pusa na kami! ;D
Finished!
(http://img.photobucket.com/albums/v70/jojod818/OPA549T_Buffered/GCIAB_05.jpg)
Sir Jo,
found it difficult to source the yellow (polyester) cap - where to go bro?
What buffer did you use in your restored GC?
Looks like another DIY'd amp to beat the expensive amps ;D
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mukhang matindi na naman eto jojo, isang dangkal ang liit.... parinig ha.
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Maririnig din natin yan sa Nov. 27...... isang malufet na invention na naman ito ;D
Halatang walang pasyente si Doc ngayon ;D
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Doc J - pahiram? ;D
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DrkyGeli,
Alam ko mabigat yan ako na maguuwi after ng session.. ::) ::)
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OPAMP rolling time na! ;D
(http://img.photobucket.com/albums/v70/jojod818/OPA549T_Buffered/GCIAB_08.jpg)
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Sir Jo,
found it difficult to source the yellow (polyester) cap - where to go bro?
What buffer did you use in your restored GC?
Looks like another DIY'd amp to beat the expensive amps ;D
Sir,
Those caps are available at Deeco, but if your kinda adventurous like I did, try Mickey of Silver Strings (he has a page at WS) and get some Auricaps. The Vishay metal film resistors are my personal stocks.
I designed the buffer, it's a simple NI config with a gain of 3 and has a first order low pass for bandlimiting. It's in a piece of paper, I'll post it if you need it, just need to raw it first.
I hooked it to my Kebao and watched movies using the amp, I liked it. Guess I'm not buying any expensive amp any time soon.
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kwela boys,
next session dadalin ko para madinig nyo din. since may chassis na, sinama ko na sa rebuild yun mga parlor parts.
;D
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Maririnig din natin yan sa Nov. 27...... isang malufet na invention na naman ito ;D
Halatang walang pasyente si Doc ngayon ;D
Hindi naman sa wala, just taking some time for myself. Nakakahiya na kasi yun itsura nun dati eh, dugtong-dugtong na yun mga wires, nginatngat pa! Naturingang gumagawa ng amp pero yun sariling amp mukhang project sa school eh. ;D ;D ;D ;D
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aHobbit,
Here it is, nothing fancy, it's very simple too. Tested it successfully using LM1875, LM3875, LM3886, OPA549, OPA541, TDA1514, and TDA2050. Other chips to follow soon.
You can adjust the 2K feedback resistor with respect to the chip used. LM chipamps operate well at higher gains so you can change the feedback resistor to 1K for a unity gain buffer/preamp.
You can also use PC201 boards for prototyping, just watch out for stray capacitance and other parasitic elements in the layout.
As always, choice of opamps is dependent on the user. For testing purposes, any low noise, high GBW opamp can be used.
HTH, :)
Goodluck,
JojoD
(http://img.photobucket.com/albums/v70/jojod818/OPA549T_Buffered/Buffer-JojoD.jpg)
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Doc J - pahiram? ;D
Sure, ikaw pa. ;)
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kwela boys,
next session dadalin ko para madinig nyo din. since may chassis na, sinama ko na sa rebuild yun mga parlor parts.
;D
Galing mo talaga DrKygeli.. Congrats saw that amp before pinagyabang mo pa ( sa loob loob ko lang hmmm iba itsura).. hehehehe at least now pwede mo na pagyabang ulit sa akin pogi na eh.... ;D ;D ;D ;D ;D
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Galing mo talaga DrKygeli.. Congrats saw that amp before pinagyabang mo pa ( sa loob loob ko lang hmmm iba itsura).. hehehehe at least now pwede mo na pagyabang ulit sa akin pogi na eh.... ;D ;D ;D ;D ;D
oo nga eh, nakaka hiya talaga yun dati itsura nito, late na ng na realize ko. buti nga wala pa candy at tootsie roll nun bago binahayan ng mga alaga ko dito. ;D ngayon may pusa na ako, humanda sila. ;D ;D ;D
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. Guess I'm not buying any expensive amp any time soon.
Why should you? Your valve-bufferred GC sings well beyond those expensive commercial amps in the market that you may consider. Your crafts are basically the same as those sold more expensive than those you are planning to buy.
It is always good to waste money on sound gears that will really deliver - and you have it already at dirt-cheap cost! ;D
So the yellow caps are called auricaps - is that what you meant?
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Why should you? Your valve-bufferred GC sings well beyond those expensive commercial amps in the market that you may consider. Your crafts are basically the same as those sold more expensive than those you are planning to buy.
It is always good to waste money on sound gears that will really deliver - and you have it already at dirt-cheap cost! ;D
So the yellow caps are called auricaps - is that what you meant?
the yellow caps are MKP (metallized polypropelene, hope i got it right ;D), the auricaps are premium grade brands. Deeco has MKP too, more cheap because auricaps are 10-20X more expensive but it's worth it especially if you implement it properly.
;D ;D
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Hi anyone looking for LM3875T I have four pieces I can sell...P350 each. Of course I left some for myself. ;D I wasn't intending to sell them but I need funds to finance my project.
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Uy mura yan, bili bili na.
Garp,
Mukhang may binabalak ka na naman ha. ;D
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Hi anyone looking for LM3875T I have four pieces I can sell...P350 each. Of course I left some for myself. ;D I wasn't intending to sell them but I need funds to finance my project.
pre sent u PM thanks
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si Boy Kati pala may masamang balak ;D ;D ;D fishhhhhing!
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Uy mura yan, bili bili na.
Garp,
Mukhang may binabalak ka na naman ha. ;D
Yes sir am ATTEMPTING a tube dac. Most parts I have already, just one more week darating na yung order ko sa Farnell. Sobrang gastos ko sa receiver.
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pre sent u PM thanks
sent you PM.
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Yes sir am ATTEMPTING a tube dac. Most parts I have already, just one more week darating na yung order ko sa Farnell. Sobrang gastos ko sa receiver.
uy! goodluck! talagang ginawa mo na lahat ng possible scenarios ha. yakang-yaka mo yan bro! ;)
keep us posted naman, maybe one of the sessions ay madidinig na namin yan. ;D
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Thank you Jojo. ;D I really hope it works. Will keep you posted.
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Thank you Jojo. ;D I really hope it works. Will keep you posted.
It will, ikaw pa. Tell me if there's anyway I can help.
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Sir JojoD818,
baka meron kayo dyan 50 watts transistor amp design yung mura lang iassemble, gagawa kasi ako para sa project namin. yung mga pyesa mabibili sa raon/deeco.
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Sir JojoD818,
baka meron kayo dyan 50 watts transistor amp design yung mura lang iassemble, gagawa kasi ako para sa project namin. yung mga pyesa mabibili sa raon/deeco.
replied to your PM. good luck sa school. ;)
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For those still "wondering" how a "gainclone" sounds like, please take a moment and read this man's story, or it can actually be called a journey since this guy started his love for audio in the early 60's....
and which amp he ended up using! :o
http://www.trutek-uk.com/Nicks_audio/audio.htm
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...not just a leisure journey. fo me it's a journey in luxury! 8)
wish i can "be" there to fully hear what he so passionately preaches...
can definitely pass up for audio-biography 8)
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...not just a leisure journey. fo me it's a journey in luxury! 8)
wish i can "be" there to fully hear what he so passionately preaches...
can definitely pass up for audio-biography 8)
I was actually looking at his 300B monoblocs when I read he mentioned the gainclone, that made me read the entire page! ;D ;D ;D ;D ;D
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For those still "wondering" how a "gainclone" sounds like, please take a moment and read this man's story, or it can actually be called a journey since this guy started his love for audio in the early 60's....
and which amp he ended up using! :o
http://www.trutek-uk.com/Nicks_audio/audio.htm
Since I heard my GC and some of its relatives, there is no going back to the piers or AV shops anymore.
Don't get me wrong - I still have the open mind to hear anything coming out in the market, perhaps even the new digital amp topology. All my present surplus amps are good paper weights, including a dual mono blocks, a branded class A amp, Sansui's, etc. - though I still enjoy them, not their sound - but their looks and built - work of arts of yester years! The Yamaha is just my utility cinema amp, but its pre-out is the one that drives the GC. One good surplus amp is just my subwoofer driver.
Nice link to a testimonials. Unlike eXg, I am quite thankful I have not been there - and I saved myself lots of money and efforts. And am thankful I braved the unpopular - to build and use GC. And I dont regret a bit today. No itch of upgrade on the amp side, no SARS for valve.
I use vynil, CD, HDCD, DVD and surplus Hi-Fi VHS (audio only) as my stereo sources.
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sir Jo, a GC is only for 2-channel stereo listening ... right? in addition, ano ba ang features nito? will the price depends on its features ? tnx ;D
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sir Jo, a GC is only for 2-channel stereo listening ... right? in addition, ano ba ang features nito? will the price depends on its features ? tnx ;D
yo! GCs are not just for 2-channel listening, I have built (successfully) several 5 channel GCs for use on HT setups.
i am not clear as to what feature you are asking but a GC is bit unusual and small, but it is still an amp. It has thermal and overload protection too.
I have tried heating the heatsink of one of my GC with a zippo and it just shutdown and returned to normal operation when it cooled down. ;D Some experiment huh?!? ;D ;D ;D ;D ;D
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mga sir .. san po nakakabili ng metal film resistor, polysterene caps and vacuum tubes....? most of the shops kasi sa raon eh wala.. or meron lang siguro akong nalampasan...
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try mo sa Silver Strings. go to wiredstate.com meron silang page dun. look for Mickey. ;)
HTH,
JojoD
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Also try RS Components and Farnell.
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thanks sir jojo.... :)
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JojoD
I was very late during the EB. sorry bro I wasn't able to give you the LM12, anyway it is still here.
Very busy ako ngayon di ako maka diskarte sa hobby ngayon, daming pending na projects
hope to finished iif time permits.
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JojoD
I was very late during the EB. sorry bro I wasn't able to give you the LM12, anyway it is still here.
Very busy ako ngayon di ako maka diskarte sa hobby ngayon, daming pending na projects
hope to finished iif time permits.
Hey no problem! Sayang nga at di tayo nagkitakita. :) Next time will do....
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sent you pm sir jojo. thanks
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sent you pm sir jojo. thanks
(http://img.photobucket.com/albums/v70/jojod818/JD%20Labs/j06.jpg)
time to ramble_on ;D
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(http://img.photobucket.com/albums/v70/jojod818/JD%20Labs/j08.jpg)
Thanks!
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WOOOOOOOOOHOOOOOOOOOOOOOOOOOOOO! :o
time for some serious listenin'!
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ganda :D linis :) ano po specs nyan? ;D
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bunblebee,
NIGC @ 56W per channel
2 selectable inputs
TBM Log Pot
Spkr Delay with fast cutoff during turn off
1000VA Tranny
Discrete Diodes
JojoD
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jo,
talagang improve na GC amp mo pre.... need some upgrades na hehehe
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jo,
talagang improve na GC amp mo pre.... need some upgrades na hehehe
;D ;D ;D
mabuti na yun mag improve kaysa maging worse. ;D ;D
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JojoD,
Ganda naman ng front panel... san ka bumuli ng aluminum? ???
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JojoD,
Ganda naman ng front panel... san ka bumuli ng aluminum? ???
marami nyan sa paligid ng arranque market! try mo sulimco, tapat ng TIP nagtitingi sila ng aluminum, i bought a 3/8 in thick aluminum panel there once!
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NI LM3886 amp with one tranny per rail...
(http://img.photobucket.com/albums/v70/jojod818/JD%20Labs/k05.jpg)
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playing with WS's Tono pre...
(http://img.photobucket.com/albums/v70/jojod818/JD%20Labs/k07.jpg)
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wala kong masabi sa mga nilalang mo master :o >:D
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malapit ka na pong maging alamat sir jo! :)
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malapit ka na pong maging alamat sir jo! :)
nakuh wag naman poh! ;D
diba puro yumao na lahat ng alamat? ;D ;D ;D
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void na lifetime warranty natin nyan kapag naging alamat si master ;D ;D ;D
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mukhang mabigat itong amp na ito ha
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malapit ka na pong maging alamat sir jo! :)
hahahhaha wag naman...
pre nakahanap ka ng stylus for your pioneer?? ;D ;D ;D
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o sige rephrase...living legend! :)
sir hans, i got an entry level shure cart for my technics.
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bump ;)
(http://groups.msn.com/_Secure/0QAAjY0oSNzxPj2RmkE7IxbuNnqHSvpfH2Z1V2aMLp38ruXLzUIVJysPr3TNTC6goSrucsx7Hal7Cddrwe7EIt1YmQPg7!Sl7IABNAFMASQA/opa0.JPG?dc=4675530104820148158)
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I've seen projects from Rod Elliot.
http://sound.westhost.com/project88.htm
http://sound.westhost.com/project101.htm
Any comments?
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rmpmla: nice casing, did you make that or can it be bought somewhere? thanks
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rmpmla: nice casing, did you make that or can it be bought somewhere? thanks
john5479, thanks. this is just DIY. the aluminum sidings are heat sink bought from DEECO. while the aluminum top and bottom cover was bought from aluminum/glass store. front and back plate is a 3 or 4mm acrylic plastic left-overs. not that difficult to build the casing.but you need small hands to put-in the gainclone parts. :)
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I've seen projects from Rod Elliot.
http://sound.westhost.com/project88.htm
http://sound.westhost.com/project101.htm
Any comments?
p88 is a non-inverting opamp topology capable of accomodating most source available today. however p88 is only a linestage and if you need a phono stage, then p06 must also be built along with Rod's psu for a complete standalone solid state preamp.
p101 is as what some of the guys say is a souped up version of the p3A (but with a lower wattage), which is one of the contending rival of the AKSA p55. though the popularity of the p3a biased into class a is now attracting more attention, the p101 is still loved by those who wish to build a mosfet output power amplifier.
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rmpmla,
congrats sa bago mo amp. :)
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rmpmla,
congrats sa bago mo amp. :)
thanks. na-miss ko na nga yung amp na to. i made three of these for friends but none for me :( .
my consolation, surplus Sony amp freebie dun sa isang owner. mas preferred nya raw yung sound nung gainclone amp.
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p88 is a non-inverting opamp topology capable of accomodating most source available today. however p88 is only a linestage and if you need a phono stage, then p06 must also be built along with Rod's psu for a complete standalone solid state preamp.
p101 is as what some of the guys say is a souped up version of the p3A (but with a lower wattage), which is one of the contending rival of the AKSA p55. though the popularity of the p3a biased into class a is now attracting more attention, the p101 is still loved by those who wish to build a mosfet output power amplifier.
Thanks rmpmla. I've been doing a lot of reading lately. I'm having a hard time understanding things on my own. Anyway, is this the right thread to post my DIY questions? Kahit nde about gainclones?
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Thanks rmpmla. I've been doing a lot of reading lately. I'm having a hard time understanding things on my own. Anyway, is this the right thread to post my DIY questions? Kahit nde about gainclones?
not rmpmla but maybe you should open a separate diy amp thread for your questions.
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hmmn . . . mukhang may bagong nahuhumaling sa GC ;D
The cheap DIY to contend for the expensive boutique amp! The most appropriate match for the difficult modern low-sensitivity quality speakers of today IMO. ::)
The digital T-amp following very close :o
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testing lang...
BufferOPA627+BUF634 & LM3886
(http://us.f3.yahoofs.com/users/41a9412fzfccc5942/9fbd/__sr_/4295.jpg?phlT91CB9lNf4anV)
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First try on ESP P88
(http://us.f3.yahoofs.com/users/41a9412fzfccc5942/9fbd/__sr_/93d1.jpg?phtFA2CBBB4BLioN)
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2nd try
BufferOPA627+BUF634 & LM3886
(http://us.f3.yahoofs.com/users/41a9412fzfccc5942/9fbd/__sr_/4295.jpg?phn_f2CB2dlf4anV)
First try on ESP P88
(http://us.f3.yahoofs.com/users/41a9412fzfccc5942/9fbd/__sr_/93d1.jpg?phn_f2CBo_lJLioN)
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My GC story since last year - inspired by regulated PSU of carlosfm
Bought this Pio SA8800 beauty for 1k. ;D
(http://usera.imagecave.com/aHobbit/GC/100_0011-pioSA8800front.jpg)
Wow, it has pre-out and main-in! :o
(http://usera.imagecave.com/aHobbit/GC/100_0013-pioSA8800back.jpg)
Good PSU, chassis, busted amp stage! >:(
(http://usera.imagecave.com/aHobbit/GC/100_0004-PSUcaps.jpg)
What to do? ???
(http://usera.imagecave.com/aHobbit/GC/100_0001-topinternal-labeled.jpg)
replace original TO3 transistors with 2x LM3886NIGC and 2x TO3-based LM338 regulator ::)
(http://usera.imagecave.com/aHobbit/GC/100_0002-heatsink-labeled.jpg)
(http://usera.imagecave.com/aHobbit/GC/100_0003-LMs-closeup.jpg)
The surgery done! 8)
(http://usera.imagecave.com/aHobbit/GC/100_0006-bottominternal-labeled.jpg)
(http://usera.imagecave.com/aHobbit/GC/100_0007-btmheatsink-labeled.jpg)
(http://usera.imagecave.com/aHobbit/GC/100_0008-PSUbottom-labeled.jpg)
the tiny regulator board!
(http://usera.imagecave.com/aHobbit/GC/100_0009-regcktbrd.jpg)
Surgery check-up includes snuberizing the reg PSU, changing the feedback&Rin to lower values to improve DC offset. For now, enjoy the 8.3 with the impostor Pio SA8800. What a sound! :D
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aHobbit,
Congrats on your gainclone powered Pioneer Amp :). This route takes away the burden of making nice looking chassis . i plan to do the same on the Kenwood receiver i bought and that was a year ago :-[.
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very nice work!
how many volts does the reg sink?
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aHobbit,
Congrats on your gainclone powered Pioneer Amp :). This route takes away the burden of making nice looking chassis . i plan to do the same on the Kenwood receiver i bought and that was a year ago :-[.
Naunahan mo nga ako doon eh. Kinakartada ko yon tapos biglang may nakabili na. suportahan taka on the kenwood surgery.
Not only did I use the chassis, but also the pre-amp stage including the phono input. including the vanilla features (kapag bored na ako) - different bass/treble center freq, loudness, etc etc. And since it has main-in and pre-out, I can mix and match. This also serve as power amp for my RX-V630 pre-out (so I use newer yamaha pre-amp stage).
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how many volts does the reg sink?
32Vac jumps to 44Vdc. I probably sank about 10V. I cant remember my figures anymore. I have to revisit my diagram.
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Naunahan mo nga ako doon eh. Kinakartada ko yon tapos biglang may nakabili na. suportahan taka on the kenwood surgery.
Talaga :). Actually, tinawagan ko rin yung seller ng Pioneer Amp na yan sa Buy and Sell kaya lang nabili na raw. Pareho din pala ang balak natin.
PM kita once inumpisahan ko na. ang dami ko kasi naka-linyang dapat wala pa nga lang free-time.
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wala pa nga lang free-time.
Istorbo talaga itong trabaho sa hobby eh ;D
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Istorbo talaga itong trabaho sa hobby eh ;D
;D ;D
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update :)
(http://groups.msn.com/_Secure/0QQCLGfkSSGhd139MxRoLLJvNCdlTcha2f6*vmycfvbJy8DAUqDEkcZuIAnAOSWz!ckow9tZhndMybXLm8ayO2tjldqFbovcNsXky*KGpFZU/front.JPG?dc=4675493610068012947)
(http://groups.msn.com/_Secure/0PwAAACMSCzNgzIjLgekpSVNpC4oxhQP*s18P6uMcsgPJBo7Xm5D3qM*6*ZZV1o2oWYNzp4gVn*GDlROcUGDjOT01hr*xwctA/top.JPG?dc=4675493610562136209)
(http://groups.msn.com/_Secure/0QACNAmESzUK3yNiOLb8NCkGh2x3RCMQd0pG0P06ZG4MHt7kV5o*23IfFeVnGJtDwSh68t3B3gcAc9F3aMH2c9P9LYLFmv8MBzoyNAgBw3hc/back.JPG?dc=4675493611706426847)
bump :)
(http://groups.msn.com/_Secure/0QQDrApUSwVGnnN03899nIbSn4OKo7hFsQEdawWQtDz4Bq8f8d3jB!papgtLeQaF8WlIiNUfGG3nys!uyHYULph5Ao74F!zwdH0kpxFjtOVg/opaGC.JPG?dc=4675536555233617928)
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http://www.6moons.com/audioreviews/47labs5/gaincard.html
insides of the famed gaincard ;)
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http://www.6moons.com/audioreviews/47labs5/gaincard.html
insides of the famed gaincard ;)
thanks for the link :).
simple lang siya pero ang mahal ng presyo :'(
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Hello mga sir,
Sa wakas, natapos ko na rin basahin ang buong thread na to! Wala akong experience sa electronics pero this thread (and the other referenced pages) has convinced me na kaya kong subukan at least yung basic na gc.
Ako newbie pero yung isang kuya ko hindi so I am wondering if this amp
http://www.diyaudio.com/forums/showthread.php?s=&threadid=54571&perpage=10&pagenumber=1
can be built using raon parts?
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Maganda kasi reviews dito e
http://www.diyaudio.com/forums/showthread.php?s=&threadid=54571&perpage=10&pagenumber=28
it uses lm3886 and lm318
quoting:
"The best description I have of the sound of this amp compared to my best GCs is that it sounds very much "class A". Its sound compares well to (or better than) a Krell or an Aleph"
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I am wondering if this amp
http://www.diyaudio.com/forums/showthread.php?s=&threadid=54571&perpage=10&pagenumber=1
can be built using raon parts?
It can be built using Raon parts alright ... but it may not be the the same actual sound as developed in the diyaudio thread.
They have identified specific parts for the kit, the building technique that goes in the board with virtual ground etc, maybe a challenge to appreciate.
I am just waiting for them to offer it as kit and am quite decided to get at least a number for my ultimate. My problem now is time. Kit will give you saving in terms of planning/execution time, test/assembly effort, and specific part searches. It maybe more expensive though - but money can be gained some other time, whereas time cant.
As to it sounding like a Krell or Aleph is not really news in the GC community. This new implementation initiated by mauro has the goal of actually disproving esoteric mentality in the so-called high-end market.
I suggest start with basic GC, with careful implementation of power supply and grounding technique - and that in itself can be translated to big savings and relative sonic advantage at par with expensive typical commercial amps. Only will require precious time.
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Yes, I'll try doing the basic gc. lm1875 and generic parts muna. From there, bahala na.
Sir aHobbit, do you have an idea how much mauro's kit will cost when it comes out?
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Sir tony, by using snubberized power supply does improve the quality of sound of gainclone?
I 'm planning to use 8 chips of opa549, bridge- parallel configuration, what is the current rating of the transformer I 'll be using?
thanks in advance...
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try to consider the higher VA rating suggested if you'll be using the amp with lower impedance loads.
JD
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Sir tony, that transformer is available only for custom made, if you have still available I'll buy it :)
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sir jojo, the rca jack from RS is available through internet only?BTW, sir what is the model of RCA jack you used in your gainclone?thanks
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Yes, I'll try doing the basic gc. lm1875 and generic parts muna. From there, bahala na.
Sir aHobbit, do you have an idea how much mauro's kit will cost when it comes out?
I think they are now seling it for USD 100.00. This includes all the board and board components. You will have to supply the transformer. Quite expensive though, but the comments of mauro and the guys who got involved with the three versions are into comparison of the amp into exotic amps. If you are after such level, the cost is not bad - you will have a decent looking, professionally made boards + good protection circuitry of LM3886 made in a very small real estate + the components are choice parts (whatever that may mean). Either prepare a pre-amp for it or use it direct for your high sensitivity speakers.
... by using snubberized power supply does improve the quality of sound of gainclone? I 'm planning to use 8 chips of opa549 ...
Am hijacking to answer ;D. With OPA549, experimenters did not note an improvement. For unknown reason, the LM3886 seems to react with snubbers, and to date, it is still being debated upon and good deal of technical tools are being used. But real implementers (I mean, majority) have stated a clear improvement. I just thought it may have to do with what kind of speakers you have - thoug they have same LM3886, their speaker preferences varies.
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you can try "podmoon" in legarda, show them the specs i gave, and the core size and ask them for a quote.
i do not have them now but making them is no big deal! i can make one for you!
Sir Tony, mga magkano guesstimate nito (say at 600VA). thanks
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suggestion ko lang mag group buy kayo ng tranny, that way mas makakamura kayong lahat. then ask tony for assistance sa mga contacts niya. mas maganda nga kung si tony mismo ang gagawa ng tranny (walang underrating, palaging rated). mga 20 pcs pataas ang starting batch pwede na siguro. o diba mas ok yun?
;)
nakasubok na kasi ako ng pangit na tranny sa gc, ang pangit ng bayo, palaging supot ang tunog. :P :o
ganyan siguro talaga kaimportante ang transformer, I'm sure Tony has some numbers to explain this phenomena.
remember...
bad tranny = supot sound
good tranny = excellent sound
;D ;D ;D
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Sir Tony,
where did u get your LM3886 board? :o :o Is it the BrianGT one? ??? ??? Wow, I can only say I want to have that kind of thing! ;D Kapag done na sir, pwede ba parinig? ;)
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master tony,
malapit na ba! ;D i'm sure ganda tunog nyan! ;D
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What are you waiting for... mag group buy na kayo kay Tony ng trafo!
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2ny,
since you are very well aquanted with different trafos, I would like to ask some questions.
what is the difference between a torroidal and an EI core tranny if both have the same sec voltage and current ratings?
for example a torroid and an EI core with 32-0-32 @2.5A... what would be the difference between the two? will one have more power than the other? will one sag under full load? please assume full load at 2.5Amps.
thanks...
PS:
sana hindi ito kamukha nun tanong na... "alin ang mas-mabigat? 1-kilo na bulak o 1-kilo na buhangin?"
If ever the EI core should become the underdog, would you be so kind to offer what adjustments must be made to the EI core to meet the standards of a torroidal?
thanks again...
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i know that "raon" trannies are poorly rated and that is why I have maintained my own industrial winder too (I have been accepting orders for industrial power managements since last year).
back to the main experiment...
but let as say that the EI core we are talking about is "exactly" rated at 2.5Amps, no "raon" rating if you may. this means the EI and the torroid specimens are of the same ratings, would the torroid fare much better than the EI under load? if yes, then wouldn't a 25-50% increase in the EI's specs match the torroid's capabilities in terms of power delivery?
in short, is it possible to match or even surpass a torroid tranny by designing a much higher EI core tranny?
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sure!
I would pick the EI anytime! the only reason to go torroid is its low weight, and low footprint!
i doubt torroids can match EI's in terms of power delivery!
ok so just to make it very clear to my troubled brain (sobrang busy kasi)...
1. a torroid tranny with [email protected]
2. an EI core tranny with [email protected]
assume both at full load (2.5A)
both will perform same power delivery and voltage sag characteristics yes?
--------------------------------------------------------------------------------------------------
one more thing, which is more efficient? torroids or EIs?
let's say the torroid has 80% efficiency, this means it can shellout a guaranteed 2A right?
let's just assume that all loads are resistive and presents a constant load. i'm having trouble with my calcs cosine and tangents.
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Sir Tony,
where did u get your LM3886 board? :o :o Is it the BrianGT one? ??? ??? Wow, I can only say I want to have that kind of thing! ;D Kapag done na sir, pwede ba parinig? ;)
i know somebody from angeles city who has a set of these lm3886 boards and is selling them, interested?
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maximum efficiency is acheived when core loss equals copper loss!
what you were probably trying to say is regualtion! which for a rated output current, say 2.5amps in your case, is the ratio of the no load voltage minus the loaded voltage devided by the loaded voltage times 100% this is according to american standards. the british have it devided by the no load voltage x 100%, which does not give very big difference at all!
current delivery is dependent on the wire size as drawn out by the load!
nope, I wasn't pertaining to regulation. I was asking about loss in the transfer of power. but as you did mention regulation, then which one also regulates better?
also, how about thermal management, any comments on both torroid and EI?
and lastly, is it just really the height? no power loss or more power or this better than that? i hope i'm making sense.
i'm sure most of our local diyers here can benefit from this.
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as i said before, you will miss nothing if you just used ei's
this is the best part of all and that's all I need.
thank you.
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Makikigulo lang po ;D Yung Hammond transformers po ba, ok?
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master tony,
what would be the effect if the power xformer is vibrating and hum will be heard?
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======
from what i read at diyaudio, ok yung mga hammonds! btw me local distributor ba yan dito na alam ka?
AMX yata meron. Farnell din (nakita ko sa catalog).
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master tony,
what would be the effect if the power xformer is vibrating and you hear humming?
mere annoyance! you can tighten the bolts on the traffo end bells, if this does not cure the vibrations and humming, you can shim the coils using wood shaped into wedges!
a dip in insulating varnish ussually takes care of this!
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kakairita nga eh! >:(
thanks, will try your suggestions! :)
mere annoyance! you can tighten the bolts on the traffo end bells, if this does not cure the vibrations and humming, you can shim the coils using wood shaped into wedges!
a dip in insulating varnish ussually takes care of this!
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andy,
tama si Tony, kulang lang sa siksik yan. kung mdali mo lang makakalas mas maganda talaga kung malalagyan mo pa ng mga red fiber o di kaya stick ng bar-b-q sabay sawsaw sa electrical varnish, ayus!
had the same problem before pre, nagmamadali kasi ako siksikan ng EI kaya ayun, parang may vibrator tuloy.
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kasama ba sa varnish sauce yung e-core kpag sinawsaw! ;D
andy,
tama si Tony, kulang lang sa siksik yan. kung mdali mo lang makakalas mas maganda talaga kung malalagyan mo pa ng mga red fiber o di kaya stick ng bar-b-q sabay sawsaw sa electrical varnish, ayus!
had the same problem before pre, nagmamadali kasi ako siksikan ng EI kaya ayun, parang may vibrator tuloy.
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kasama ba sa varnish sauce yung e-core kpag sinawsaw! ;D
oo pre, kaya papatuyuin mo muna mabuti tapos lihahin mo yun mga exposed na EI para mapinturahan ulit. dapat siksik na siksik. para hindi mahirap ipasok yun EI lagyan mo ng lubricant, kahit light machine oil pwede pero wag mo pabayaan malagyan yun copper winding ha, conductive kasi yun oil eh.
tyagaan lang pero mahuhuli mo din yan. make sure sa labas ng bahay patuyuin yun core, medyo hindi maganda amoy nun electrical sauce. ;D
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i know somebody from angeles city who has a set of these lm3886 boards and is selling them, interested?
How many pieces?
How much each piece?
Does it include the parts and the supply board/parts?
thanks!
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sure!
I would pick the EI anytime! ...
Me too!!! 8) 8)
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email sent...
i know he has a pair of boards already stuffed with parts, ic included, the psu must come with the boards, as i got mine that way.
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thanks! :)
andy,
you can get the "remington" air drying clear electrical varnish, cost is around 270 bucks! an ice cream container that can fit your traffo is needed.
you have to preheat your traffo for best results! you can put your traffo atop a small steel plate and heat up in an oven. attach some wires so you can handle your traffo.
once heated, dip your traffo in, and immerse untill the bubbling stops.
lift it up and let it drip. when dripping stops you can hang it under the sun to dry!
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aHobbit,
huwow! LM4780 pala target mo. review ha... para makagawa din ako.
btw, stereo na yun so kung dalawa board ano yun naka bridge or parallel?
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aHobbit,
huwow! LM4780 pala target mo. review ha... para makagawa din ako.
btw, stereo na yun so kung dalawa board ano yun naka bridge or parallel?
LM3886 sir! Actually I have 6 of these chips, plus 6 of LM338 regs. For lack of time, cant complete except the 2 working channels I made on my impostor pioneer. I want to complete 5 channels for HT. Medyo BrianGT yung board niya, so may mga papalitan pa ako sa board. If the price is OK, I may proceed. Also the regs will also need some attention too. But at least if PSU is included in the boards - it may lessen my time to complete.
Anybody selling two more vintage silver pioneer junks? ;D ;D ;D
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LM3886 sir! Actually I have 6 of these chips, plus 6 of LM338 regs. For lack of time, cant complete except the 2 working channels I made on my impostor pioneer. I want to complete 5 channels for HT. Medyo BrianGT yung board niya, so may mga papalitan pa ako sa board. If the price is OK, I may proceed. Also the regs will also need some attention too. But at least if PSU is included in the boards - it may lessen my time to complete.
Anybody selling two more vintage silver pioneer junks? ;D ;D ;D
I see, I love 3886 sound too, very fast and dynamic. I was under the impression that the 4780 contains 2 3886 in one chip. I was planning to parallel it and use 1 chip per channel. only problem is the pins are too close and so I plan to do it the old way... point to point wiring. ;D ;D ;D
I'm sure you can talk some guys in pier to sell you those "beyond repair" amps they have. excellent source of beautiful casings. :)
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I was under the impression that the 4780 contains 2 3886 in one chip.
the lm4780 in fact uses 2 lm3886 dies in one package! i have info that maybe by next year, lm3875 may no longer be in production!
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the lm4780 in fact uses 2 lm3886 dies in one package! i have info that maybe by next year, lm3875 may no longer be in production!
good that you know that too!
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@aHobbit,
got reply from from ferdie, will forward to you, in case you missed ;D
these psu boards come with the gainclone boards!
(http://i20.photobucket.com/albums/b201/tecson/gaainclones/Cimg0274.jpg)
these are the gainclone boards i have, a pair each for lm4780, lm3886,lm3875:
(http://i20.photobucket.com/albums/b201/tecson/gaainclones/Cimg0283.jpg)
this is a snubbered psu board i made, again FR4 boards wer used, i heatsinked the MUR860's since they will be dissipating more than 1watt a piece!
(http://i20.photobucket.com/albums/b201/tecson/gaainclones/Cimg0301.jpg)
(http://i20.photobucket.com/albums/b201/tecson/gaainclones/Cimg0302.jpg)
(http://i20.photobucket.com/albums/b201/tecson/gaainclones/Cimg0304.jpg)
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@aHobbit,
get in touch with ferdie yet? ;D
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hi guys
im new in this foum! thanks to 2ny
im selling my LM3875 stereo gainclone kit with power supply board at very reasonable price. for those who are interested please feel fee to email me.
Best regards,
ferds
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hi ferds,
welcome to the forums, can you post your projects here? thanks
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hi 2ny
thanks,
sure i will post my audio projects here. my projects are usb dac , bridge-parallel gainclone amp using opa549 8pcs per channel, amplifiers from the book of randy slone , mosfet power amps and many other.
hope to post them all here.
ferds
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the more the merrier! ;D
i have been trying to get MGR, c3po, naldhy and others to post in this forum! as i believe many can be benefited!
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Sir tony, take a look at this new powerful chip amps from National, LM4702!
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thanks,
national raised the bar a couple of notches! ;D
i have the national lm4701 chips, time to get my contact in honkong for some of these chips ;D
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which reminds me! in the early 80's national came out with the LM391 devices in a 16pin dip package and was intended as drivers just as these LM4702's
i built a couple of these amps and they were wonderful amps! ;D
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khelo,
dito mo na post yun amp mo since gainclone din yun! ;D ;D ;D
nag start ka na ba magbuo?
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thanks sir jojoD,
hindi pa nga rin eh. But, a soon as i get my bonus, bibili na ko ;D
I'll try smaller version muna TDA2050 :-\. mas compact at 5 pins lang and less part... ;D
mas exciting to pag napatunog ko, kya uunahin ko na muna to. tpos dun na ko s mejo malaking TDA7294...
sir jojo, magkano itong TDA2050?
mery xmas ;D
still rem? xmax not xmas... kong hei fat choi... u told me before ;D ;D ;D
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try mo rin yung LM1875...5pins din. ;D
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try mo rin yung LM1875...5pins din. ;D
Yup, will recommend going LM1875 than TDA2050 as first experiment - it may become your permanent system (this is a warning!) ;D
was not able to update you - that of ferds, he has 3875, not 3886: so did not pursue it
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you can try the LM1875T pero for me oks din yun TDA2050 for first project. TDA2050 price range is 80-90 pesos only. I think LM1875 is somewhere 100+ pesos (tagal ko na di bumili eh).
tutunog yan, maniwala ka sa akin. huwag ka matakot kapag hindi tumunog, ang dami namin dito sa gainclone thread na tutulong sa iyo kung may problema. ;)
warning: same as aHobbit and 2ny, i also recommend LM1875 because of it's superior sonics over the TDA2050. however, I have personally and intentionally brutalized both chips as part of an r&d project in the past and both chips can stand up to a diyers itchy fingers.
I sometimes wonder why NS didn't include the LM1875 in their Overture series. ::)
I forgot na re xmax pero max excursion ng voice coil yun ;D Merry Christmas to all!
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salamat s inyong lahat mga bosing!!!
sa wakas nakabili n rin ako 8) LM1875... d2 sa akihabara, 90 pesos each.
cguro after our christmas party uumpisahan ko to. bka dun nlng sa amin sa bataan, andun kc mga tools ko
the problem is wlang internet computer ko s amin s bataan, kelangan ko png pumunta ng bayan pra makapag internet pra makapag tanong sa forum :( hopefully, tumunog... if ever n hindi tumunog :'( :'( :'(
sir jojo,
ito ung reply mo sa thiel/small parameter threads ;D ;D ;D
yun Xmas parang Xmax dapat yun. Yan yun maximum cone excursion measurement ng driver mo.
yun Xmas = Christmas, Kung Hei Fat Choy!
biro lang ha, wag ka magagalit.
Good luck,
JojoD
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Btw, i'll use rod elliot schematic diagram :)
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;D ;D ;D
I remember na! ;D ;D ;D napatawa ako dun ah ;D
anyway, bago ka umuwi ng bataan, I suggest na mag print ka nun datasheet ng LM1875 para may reference ka na din.
ayus yan schematic ni pareng rod. ;)
kaya mo yan, basta wag mo iisipin na magkakaproblema. pag natapos mo na i-solder at mag power on ka na at medyo kabado ka... isipin mo lang na kasama mo kami in spirit. ;)
;D ;D ;D
ps: test mo muna psu mo bago mo ikabit sa gc mo (baka makalimutan mo eh). ;)
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naalala mo na rin ;D ;D ;D
nag burn na ako ng copy ng file sa cd, pra un nlang ang reference ko.
meron na rin akong na salvage na heatsink sa lumang component system. meron na rin akong transformer, 12 0 12 nga lang. sir jojo, cguro pede n rin muna tong pang testing? pero bibili rin ako nung 18 0 18...
sir jo, kelangan ko pa ba ng mica pra sa lm1875, kc pag sasamahin ko nlng cla sa isang heatsink.
thanks sa reminder ;) check ko nlng mabuti ung placement nung components, then ung power supply...
btw, may ginawa n kong layout sa corel, hindi ko lang ma insert dito...
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ok lang 12-0-12, sana lang medyo mga 3 amperes para may kaunting sipa. kung pang test at moderate listening lang oks na yan. partner mo lang easy-to-drive speakers at masisiyahan ka na sa tunog.
btrw, kailangan mo ng mica insulators dahil kung hindi ako nagkakamali V- yun tab ng mga yan kaya pag wala ka mica your shorting the negative rail to ground. remember to use a small amount of silicone thermal grease on both sides of those mica insulators, pero kung wala ka nun pwede din wala muna. yun pang screw mo sa tab ng chip dapat may plastic insulating washer din ha. kung medyo nalilito ka sa proper mounting then try searching and download National's apps notes regarding mounting their Overture series of chips.
cheers
-
ok lang 12-0-12, sana lang medyo mga 3 amperes para may kaunting sipa. kung pang test at moderate listening lang oks na yan. partner mo lang easy-to-drive speakers at masisiyahan ka na sa tunog.
btrw, kailangan mo ng mica insulators dahil kung hindi ako nagkakamali V- yun tab ng mga yan kaya pag wala ka mica your shorting the negative rail to ground. remember to use a small amount of silicone thermal grease on both sides of those mica insulators, pero kung wala ka nun pwede din wala muna. yun pang screw mo sa tab ng chip dapat may plastic insulating washer din ha. kung medyo nalilito ka sa proper mounting then try searching and download National's apps notes regarding mounting their Overture series of chips.
cheers
sir jojo,
nabasa ko sa datasheet, V- negative nga ung metal tab. pero pede rin syang walang mica kung insulated ang heatsink sa chassis :) meron akong nakuhang makapal na plastic, balak ko na un ang gamitin kong casing.. so pede na kahit wala ng ground sa chassis :)
sir jojo, cencia na mejo matanong ::)
balak kong pag samahin sa isang heatsink ung LM1875, wla bng conflict un? joining in same heatsink. anyway, insulated nman ang heatsink sa chassis ::) ???
15 0 15, 5 amperes ok na cguro to :)
-
common practice na kasi na gumagamit ng mica insulators para at ground potential yun heatsink. that way we can be sure it will not serve as an antenna for noise and other unwanted signal.
depending with the load and magnitude of the signal, V- on the other hand is constantly varying, these variations can be read as a modulation waves and can be picked up by the operational amplifier.
ayus na yan tranny mo bro.
good luck!
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ok thanks sir jojo ;)
cguro ggamitan ko nlng ng mica pra cgurado :)
pano mga bosing! babaunin ko muna ang lahat ng advice nio sa akin pauwi ng bataan...
dun ko nlng cguro ito tatapusin ;D
post ko nlng dito ung picture pagbalik ko sa january 8)
Merry Christmas and Happy New Year sa inyong lahat ;) :)
bakasyon na namin ;D ;D ;D ;D ;D ;D ;D :D :D :D ;) ;) :)
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happy new year sa inyong lahat :)
sa wakas napatunog ko na rin ang DIY amp ko ;D
wala akong masabi ang ganda ng tunog... walang distortion/ wlang hum malinaw tlaga...
salamat sa inyong lahat guys.
post ko ang picture next monday, ipinadevelop pa ng honey ko ;D ;D ;D
mike :)
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congrats!!!
ganyan talaga pag sariling gawa ang amp, napakahusay at malinaw, walang hum at distortion. ;D ;D ;D pero minsan wala din sound! :P ;D ;D ;D ;D joke lang
o di gagawa ka pa ng iba niyan?
:)
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Oo sir jojo ;D gagawa p talaga ko :) (exciting) :o
cguro ung TDA7294 naman...
sna malinaw din walang distortion at hum.
wag lang walang sound :'( :'(
;D ;D ;D
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pano ba yan meron ka ng gainclone....
eh di shootout na tayo!!!
;D ;D ;D ;D ;D ;D ;D
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khelo,
na-miss ko mag gainclone building kaya eto... pang new year's eve party gainclone ko nagamit...
(http://img.photobucket.com/albums/v70/jojod818/JD%20Labs/GC-bai-01.jpg)
(http://img.photobucket.com/albums/v70/jojod818/JD%20Labs/GC-bai-02.jpg)
(http://img.photobucket.com/albums/v70/jojod818/JD%20Labs/GC-bai-01.jpg)
pics naman ng gainclone mo!
:)
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jojo,
saan gawa yung chassi mo? type ko ;D
this time you mounted the heatsinks right, now they are 100% effective! good job! ;D
-
Hi, si JojoD ito, nakigamit ng pc may session kasi.....
From old UPS yan chassis. Buti nga tumama na ako sa heatsinks... halatang newbie ano?... ;D ;D ;D
Old din yan heatsink kaya ganyan nangyari naging patayo. Pero given the chance pahiga pa din ang kabit ko. :P
;D ;D ;D ;D ;D
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hi, :(
pasensya na mga bosing, tagal kong nwala :-\
sir jojo, meron na kong picture kya lng ayaw pumasok eh. ano kya ang probema?
pano ba e upload?
sir jo, ganda ng amp mo ;)
-
khelo,
register ka lang sa photobucket.com tapos upload mo dun yun pics mo then post mo dito yun url or image. that's it.
cheers
-
pasenya na mga bosing mejo malabo.
(http://i41.photobucket.com/albums/e258/ma_khelo/amp1.jpg)
lm1875 amp mount in a pcb
(http://i41.photobucket.com/albums/e258/ma_khelo/amp2.jpg)
lm1875 amp / rectifier and filter
(http://i41.photobucket.com/albums/e258/ma_khelo/amp4.jpg)
amp inside the wooden casing
(http://i41.photobucket.com/albums/e258/ma_khelo/amp5.jpg)
another look inside
(http://i41.photobucket.com/albums/e258/ma_khelo/amp6.jpg)
front w/ my cd player
(http://i41.photobucket.com/albums/e258/ma_khelo/amp7.jpg)
in top of my speaker
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thanks sir jo,
hayan na upload ko na rin...
although, mejo magulo ang wiring, ok din ang sound :)
ung 12 0 12 3 amps tranny ang ginamit ko, ok n din ;D ;D ;D
khelo
-
super job! you are not a newbie after all! ;D
suggestion lang, use separate ground wires for the speaker common, and solder them directly under the psu board where the two main filter caps meet. reason is to avoid ground loops, since at the juntion of the two caps, signal is very low, and dc is likewise zero. solder the transformer center there also if you are using just a siingle full wave bridge.
sisiw na yung mga malalaking chips sa yo.....
-
hindi nga lang masyadong maganda ;D
sir 2ny, thank u sa tips :)
sir, i a-apply ko yan sa nxt amp ko...
now im ready for another gainclone project ;) this tym mejo malaki ng konte...
(lm3875 / 3886 or tda7294)
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khelo,
ang tindi ng amp mo, mabuhay ka!
-
:) salamat mga bosing!
kung hindi rin dahil sa inyo, hindi rin siguro ako magiging successfull sa project ko ;)
thanks sa mga tips and advise nyo dito sa pinoydvd :)
khelo
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khelo275 ,
i noticed you mounted the heatsinks flat on the chassis, but then you provided a fan to move the air around the heatsink, you did it right the first time!
there is a law of physics which goes something like, "hot air goes up, cold air goes down".
if is for this reason that heatsinks are always mounted with the fins vertical so that effectivity is a 100%, mounted as such air in contact with the heatsinks have more room to play with and traverses the surface of the heatsink unimpeded. imagine if the heatsink is vertical but with the fins horizontal, air in contact with the heatsinks have more distance to travel. now imagine the heatsinks on its back, air under the heatsinks have a hard time to move.
heatsinks are very important for the safe operation of the amps.
you did the right thing putting a fan so that even in that position, air can still flow around the heatsinks!
keep doing it right and you will be on your way to building great amps!
-
khelo,
for "better understanding" of heatsinking try google'ing "thermodynamics", or search books regarding the subject.
-
thanks sir tony, sir jojo
mejo mabilis uminit nga ang amp ko nung walang pang fan.
kung mappansin nio 2 ang heatsink. nung una kc isa lng ang heatsink, kya lng mabilis uminit kya nag screw pa ko ng isa pang maliit sa ibabaw, tapos nilagyan ko n ng fan...
hiniwalay ko na lang ung supply nung fan...
so far wala nman akong nakikitang problema. tanong ko lng mga bosing, ok lng ba na magkatabi ang 2 transformer?
balak ko kasing lagyan ng tone control ::), cguro un nakakabit na transformer sa fan un na rin ang gagamitin kong transformer sa tone control.. 0 - 12V lalagyan ko ng regulator 7812/7912 ???
:) khelo
-
pwede as long as they are in 90 degrees position. si Tony ang master ng transformer, tiyak may mga tips yan for your application....
-
so far wala nman akong nakikitang problema. tanong ko lng mga bosing, ok lng ba na magkatabi ang 2 transformer?
balak ko kasing lagyan ng tone control , cguro un nakakabit na transformer sa fan un na rin ang gagamitin kong transformer sa tone control.. 0 - 12V lalagyan ko ng regulator 7812/7912
those are power transformers right? so no problem putting them side by side, those regulators will be fine.
-
mga sir,
nakabili na ko ng lm3886, P265 each ;)...
try ko point 2 point nlng muna ;D
-
mga bosing musta na?
tanong ko lng kung pano ko ikakabit ang polarised cap sa input ng amp? kompleto ko n ang part ng bubuoin kong bagong gainclone, lm 3886. diagram ni pareng rod elliot. ang problema ang hirap mag hanap ng non polar electrolytic :-\. hindi ko alam kung pano ang placement nung cap, kung una ba ang positive o ang negative ???
tips nman mga bosing :)
hintayin ko mga reply nio
thanks
-
una negative.
pero...
kung may pambili ka pa ng capacitor ang gawin mo bumili ka ng identical values tapos pagtaliin mo yun mga negative at yun dalawang positive ang gamitin mo, ayan may np cap ka na. pero dapat doblehin mo yun value, halimbawa kailangan mo np 4.7uf, ang gamtin mo dalawang 10uf at pagtaliin (i-series) ang mga negative terminals nito.
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thanks sir jo,
ang hirap mag hanap ng non polar electrolytic cap.
cge try ko yang sinabi mo, yan nlng ang kulang kompleto n tong gainclone ko :D
post k nlng ulit ang picture pag tpos n :)
thanks
mike
-
kung 4.7uf, gamit ka ng film types, meron sa golden mars, deeco and others...
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thanks sir jo,
ang hirap mag hanap ng non polar electrolytic cap.
cge try ko yang sinabi mo, yan nlng ang kulang kompleto n tong gainclone ko :D
post k nlng ulit ang picture pag tpos n :)
thanks
mike
Sir Mike,
Puwede gumamit ka ng electrolytic na back to back. Iyung + polarity nung dalawa magkakabit then iyung dalawang - polarity ang magiging bagong paa niya. Mas maganda kung parehas iyung value nung dalawa para iyung resultant capacitance value magiging kalahati. Ito kasi ginagawa ko kung di ako makakita ng non-polarized electrolytic. :)
Rascal101
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thanks rascal..
anyway, try ko muna single cap. negative sa source, positive sa input ng amp ;)
if ever weak ang signal, ska ko nlng papalitan ;)
naikabit ko n kc eh ;D ;D ;D
mike
-
for coupling ac signals, use of electrolytics is not optimum, you are better off using film types. 4.7uf films are not hard to find in raon.
-
where can i find film 2.2uf film caps in raon ? need some for my lm1875
-
amco, deeco, golden mars, eleshop and others, you have to be patient in looking for them..
-
mga sir, ung lm3886 gainclone ko napatunog ko na ::) , malinaw din wala ring hum/ hiss walng distortion. parehas din sa lm1875 na gainclone ko ... kaya lng ang prolema after 45 minutes of testing na distort na ung isang channel, tapos pahina na nang pahina tapos distorted pa rin hanggang sa huminto ??? :-\
diba may termal protection ang lm3886? kc nung hipuin ko sobrang init ung isa. check ko ung circuit wala namang problema. cguro hindi tutunog ung amp ko kung may problem ang circuit? ska mababa lng nman ang supply ko 12 0 12 lng :-\
may mga fake bang lm3886? hindi kya fake ang nabili ko? binili ko to sa newport...
advise namn mga bosing!
thanks
mike
-
Congrats!
Why so hot? Hindi mo ba nilagyan ng heatsink nun nag test ka?
Ask mo sa binilan mo kung orig yan binigay sa iyo.
-
thanks sir jojo,
nilagyan ko. pero cguro talagang may problema talaga ung isang chip...
masyadong mainit ung isa . ung isa hindi naman
hindi ko na naitanong kung orig ung chips... s newport ko to binili
ibig sabihin meron din tlagang fake na lm3886?
-
make sure the backside of the chip is making good contact with the heatsink, if the chips heats up more than the heatsink, then you got contact problem, have you used silicon grease?
double check your wiring, compare with the other normal channel and find out what is different from that one.
-
sir tony, diba dpat mag o-off ang chip ::) prang may termal protection din tong chip n to...
hindi ko nlagyan ng termal grease. pero may mica washer namn...
sir ok lang nman ang wiring eh. anyway check ko nlng ulit ???
-
hhmmm.. parang nawala yun post ko kanina umaga ah... ::)
anyway, check mo muna mabuti yun wiring mo. tama na i-compare mo muna ito sa working channel mo para may point to point basis ka ng pag check.
-
(http://i41.photobucket.com/albums/e258/ma_khelo/lm3886amp.jpg)
sir ito ung ginamit kong layout..
paki check kung may problema ::)
thanks
mike
-
ikaw ba gumawa ng pcb mo? check for hairline cracks or hairline shorts sa mga traces. a multimeter with audible buzzer would be very helpful in this situation. check all electrolytic polarity kung tama. pati resistor check mo isa isa baka may off value/short or open.
kapag sure na sure ka na talaga ilipat mo muna yun chip na buo para ma test mo. pero bago mo gawin yan siguruhin mo muna na tama lahat at na check mo na.
hope this helps
ps. paki sukat na din yun power supply kung tama lahat.
-
yes sir, ako gumawa nito. kamukha ito ng pcb ni rod elliot, pero i'm not sure kung ganitong ganito nga ang pcb nya...
sir jo, bumili n ko ulit ng bagong chip, kailangan eh :'( . i check ko nlang ulit sir..
pero tumugtog sya ng matagal siguro mga 45 minutes din. halos matapos nya ang isang cd ::)
hindi kc nka screw sa heat sink inipit ko lng sya, bka ung ang naging problema nag overheat.
double check ko nlng munang mabuti :-\
mike
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gumamit ka ng silicon grease sa mica insulator, ang tamang paglagay nyan, gamitin mo yung hintuturo at hinlalaki sa pag-apply, yung maging opaque yung mica okey na yon, huwag marami, sayang lang.
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yes sir, ako gumawa nito. kamukha ito ng pcb ni rod elliot, pero i'm not sure kung ganitong ganito nga ang pcb nya...
sir jo, bumili n ko ulit ng bagong chip, kailangan eh :'( . i check ko nlang ulit sir..
pero tumugtog sya ng matagal siguro mga 45 minutes din. halos matapos nya ang isang cd ::)
hindi kc nka screw sa heat sink inipit ko lng sya, bka ung ang naging problema nag overheat.
double check ko nlng munang mabuti :-\
mike
Dapat naka screw ng mabuti yan sa heatsink, then yun mga first few minutes ng operation dapat monitor mo yun heat sa heatsink and chip before leaving the amp powered on.
LM3886T or LM3886TF yan binili mo? kung TF hindi na kailangan ng mica, pero yun T kailangan ng mica insulator since V- ang tab ng 3886T. sundin mo na lang yun advice ni Tony regarding installation. Don't forget to use plastic insulators for your screw bolt and use washers if possible. Pag kabit mo sa heatsink verify mo ng tester kung walang short between metal tab ng chip and heatsink.
hope this helps.
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yes, the tabs on the uninsulated version, LM3886T is not meant to be connected direct to heatsink, so use a shoulder washer on your bolt.
-
ok n mga bosing, ;)
walang problema ang circuit, ung chip ang may problema...
pero ngaun tumutugtog n malinaw, walang hiss, wlng hum, wala ring distortion. tulad din nung lm1875 gainclone ko :D.
wla akong masabi sa mga chips na ito
ang sarap makinig ng music pag sariling gawa ang amp ;)
thank u mga sir
mike
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tama ka dyan mike :D
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my 2 version of bridge-parallel amplier, the one installed with heatsink uses op amps and the other uses drv134 with the help of sir jojod website ;D
http://i47.photobucket.com/albums/f160/blackmtx/Image068.jpg
pasensya na mababa lang pixels ng cellphone camera ko ;D
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wow ganda! congrats! :)
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guyz have you seen this kit? will it be worth the investment, based dito sa you can have it for USD106 including the shipping. are the parts available locally ganda kasi ng pagkagawa ng board nya take a look :)
follow this link:
http://www.audiosector.com/lm3875.shtml
thanks
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guyz have you seen this kit? will it be worth the investment, based dito sa you can have it for USD106 including the shipping. are the parts available locally ganda kasi ng pagkagawa ng board nya take a look :)
follow this link:
http://www.audiosector.com/lm3875.shtml
thanks
why not, the boards are bouble sided and plated thru, very had to clone here...also you will need a chassis, and power supply parts.. ;D
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is the lm3875tf available dito sa atin? where could i buy kaya? i already have a toroid transformer and a chassis and heatsinks galing sa salvaged na sakura amp :)
tatakot ako baka may nasira akong component lalo na yung lm3875 baka wala na me ma bilhan dito sayang lang yung kit di mabubuo :(
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what are the secondary voltages of that torroid?
if I remember it right, the hi current winding of a sakura amp torroid is 32-0-32, which in dc would be ~+/-45V, too much for an LM3875. if you have a lower secondary then you are in business.
:)
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is the lm3875tf available dito sa atin?
what for? just use fiber washers and mica insulators and your'e good...besides, the "t" versions can dissipate more power than the "tf" version...
-
jojo :
sir i still have to check but the sakura amp is the one used in coin operated videoke machines and looking at the size of the toroid its about 6inches in diameter have to check it pa with a multitester, i believe sir that the secondaries must only be 18-22v right?
2ny :
sir ibig nyon sabihin there is a variant of lm3875 available here without the special tf (whatever that means), sir saan po meron and how much kaya?
-
i have one piece tf version....i know they are available in eleshop...or newport in raon...
-
2ny :
thanks, ill check this coming saturday with those shops kasi ill be going to quiapo (be buying dvd's). sir san banda po yung mga shop na eto meron po bang landmark?
thanks again
-
t=metal, non-isolated tab
tf=plastic isolated tab
listen to tony, better get the "t" version for more efficient heatsinking. it can take a max dc voltage of +/-40V so a max ac of 28V can be used.
if you are salvaging the sakura amp, better salvage the heatsink too.
;)
-
what are the secondary voltages of that torroid?
if I remember it right, the hi current winding of a sakura amp torroid is 32-0-32, which in dc would be ~+/-45V, too much for an LM3875. if you have a lower secondary then you are in business.
:)
maganda 'tong balak na ito ah!
ok na 32Vac, sink mo sa LM338 regulator to give you regulated 40Vdc, tapos snubberized mo pa
snubberized gainclone ka na - what's your pre-amp?
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jojo :
sir sad to say the secondaries of the salvaged sakura amp is to high :( waahhh bibili na lang ako ng bagong transformer any idea kung saan maganda bumili eto yung hinahanap kung specs ng transformer primary 230v; secondaries 2x18 - 22v; maybe 300vac? i tried rsphilippines pero ammahal hehehe 3.1k yung nuvotem baka meron mas mura at balak ko EI na lang :)
cge po ill get the "t" version na lang, salamat po sa advise :)
ahobbit :
i will not be using a pre amp sa binabalak kong project, since isa lang source ko and i still have to figure what to use as volume pot :)
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jojo :
sir sad to say the secondaries of the salvaged sakura amp is to high :( waahhh bibili na lang ako ng bagong transformer any idea kung saan maganda bumili eto yung hinahanap kung specs ng transformer primary 230v; secondaries 2x18 - 22v; maybe 300vac? i tried rsphilippines pero ammahal hehehe 3.1k yung nuvotem baka meron mas mura at balak ko EI na lang :)
cge po ill get the "t" version na lang, salamat po sa advise :)
ahobbit :
i will not be using a pre amp sa binabalak kong project, since isa lang source ko and i still have to figure what to use as volume pot :)
what do you mean too high? ilan volts AC? you can always follow aHobbit's advice of using regulators, but that may complicate things and will also depend on your skill level - pero sa dami namin dito walang problema, for sure madami ang tutulong sa iyo.
meron si 2ny recommended na gumagawa sa may Paco yata, meron din ako winder ng tranny. Kung saan ka malapit dun masaya. ;) Beware though, mataas talaga ang bakal ngayon, especially copper and aluminum - no wonder mataas ang mga "rated" transformers. Of course, there are some "under rated" ones that you can buy cheap.
2ny, on one of his lectures says ;D... "The most expensive part of a power amplifier is the power supply."
So you may really want to consider that salvaged sakura tranny to ease your wallet's burden but should always remember - what you feed your amp will most likely be what it sounds.
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jojo :
sir sad to say the secondaries of the salvaged sakura amp is to high :( waahhh bibili na lang ako ng bagong transformer any idea kung saan maganda bumili eto yung hinahanap kung specs ng transformer primary 230v; secondaries 2x18 - 22v; maybe 300vac? i tried rsphilippines pero ammahal hehehe 3.1k yung nuvotem baka meron mas mura at balak ko EI na lang :)
cge po ill get the "t" version na lang, salamat po sa advise :)
ahobbit :
i will not be using a pre amp sa binabalak kong project, since isa lang source ko and i still have to figure what to use as volume pot :)
how high is too high. my pioneer sa-8800 has 32Vac, and use LM338 to power my LM3886 gainclone using the pre-amp of the pioneer - the LM338 mounted on the heatsink where the LM3886 is mounted - it is not even hot on the top of the cover under normal listening. Of course, last holiday season, I torture test it to distortion level - its hot but it is still alive and kicking up to now.
QC passed! ;D ;D
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jojo @ ahobbit :
mga sirs i 32v ang secondaries ng sakura, ill check dun po sa advise nila na to use lm338, how complicated kaya, im very much a newbie kaya if it will complicate baka magpalit na lang ako ng trany.
mga sirs maayos po ba mag wind yung golden mars sa raon any experience with them?
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jojo @ ahobbit :
mga sirs i 32v ang secondaries ng sakura, ill check dun po sa advise nila na to use lm338, how complicated kaya, im very much a newbie kaya if it will complicate baka magpalit na lang ako ng trany.
mga sirs maayos po ba mag wind yung golden mars sa raon any experience with them?
medyo highish nga, I checked the datasheet for the 338 and my concern would be the input voltage of +/- ~45V from a 32V-0-32V, although the max differential is +40V. but if you do consider using the sakura trany, then maybe you should shoot for an output voltage of 35V to give the 338 some +/-10V of bleeding voltage for line sags and optimum load regulation.
Sorry, no experience with their trannies here.
BTW, would just remind you that if you go ahead with the sakura tranny, you should make sure that the tranny has a 0-32, 0-32 windings so you can use LM338. They also have thermal protection as advertised but it wouldn't hurt if you'll use aHobbit's approach in mounting the regs with the chips in one heatsink. Stray capacitance however, had been debated for so long amongst hardcore GC builders with the use of such an approach. In the end, it's up to you.
:)
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jojo :
sir uhhh what about if another small tranny is used to lover the voltage from 32v to 20v pede ba yun?
thanks ulit
-
naku, magkaron ka ng unwanted power dissipation niyan.
Physics 101:
The law of conservation of energy states that energy may neither be created nor destroyed, it can only be transformed from one form to another.
You will be transforming excess voltage into heat, isip ka pa iba solution. :)
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jojo :
sir uhhh what about if another small tranny is used to lover the voltage from 32v to 20v pede ba yun?
thanks ulit
off the shelf 24volt transformers are available at deeco in raon, just get 2 of those and you are good...save that transformer for another project, or if you want you can swap it with me... ;D
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off the shelf 24volt transformers are available at deeco in raon, just get 2 of those and you are good...save that transformer for another project, or if you want you can swap it with me... ;D
OT: 2 days na lang...
Welcome back na! ;D ;D ;D
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off the shelf 24volt transformers are available at deeco in raon, just get 2 of those and you are good...save that transformer for another project, or if you want you can swap it with me... ;D
... this is another way ...
though, complication wise, you should appreciate 2 works in these 2 alternatives ...
using the trafo at 32Vac, you will need the LM338 reg, have to get the center winding of the transformer and cut it so you can have 2 separate windings, make the LLM338 circuit board and include in it the snubbers
using a purchased EI core, the simplest is to get 2x 24vac trafo, make or buy rectifier circuit, increase capacitance and install snubbers.
... the latter is much simplified in circuit works, but is a challenge in mounting inside the sakura box.
So, in your own skills, you can determine which will be easier for you.
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2ny :
cge sir pag isipan ko toroid din ba yung i swap u? what are the specs?
jojo :
di pala pede yun hehehe kala ko pede kasi two step downs hehehehe
ahobbit :
sir mukhang di ko kakayanin cguro talaga benta ko na lang yung trafo pan dagdag sa project :(
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hi,
nasa narita airport ako as i write this, i don't have a torroid, but ei's if you are interested...you can keep that torroid for another project if you wish... ;D
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2ny :
aba sir jetsetter pala sila hehehe :), im thinking of buying na lang the novutem indi ko na titipirin yung supply at andun yung buhay ng amp :)
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wise choice, fyi i am now at my home in nueva ecija for a 3week vacation, then off to russia again ;D
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welcome back tony!
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thanks ;D
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2ny,
very short vacation though? well, better than no vacation at all. 8)
makikulit,
musta na amp mo? start na ba?
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jojo:
sir di pa po pero may good news i found a good source nun mga gamit medyo nagulat nga ko mura nun lm3886tf sa kanila worth 200p lang plus a tranny 20v 3amps dual secondaries custom wind pa 450 lang, at dun din sa store na yun andaming mga high quality caps nichicon, rubycon parang andun na lahat kailangan ko hehehe :)
the store name is golden mars in front of deeco sa tingin ko i just need around 2k lahat ng components yun pwera lang yun casing yahoo yahooo!!!
ipon-ipon pa kaunti na lang :)
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makikulit,
golden mars is where i get my copper wires from and also parts like rca jacks and 5way binding posts...i have been trying to talk the owner into bringing in tubes also...and other polypropylene capacitors. eventually every diy'er looking for a good buy will come to that place...
the transformer you want is a bifilliar wound secondary, see if you can get them to wind that way for you. the virtues of a bifiliar wound secondary type transformer are many. i have used such types for the last 20 years and have never looked back..
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jojo:
sir di pa po pero may good news i found a good source nun mga gamit medyo nagulat nga ko mura nun lm3886tf sa kanila worth 200p lang plus a tranny 20v 3amps dual secondaries custom wind pa 450 lang, at dun din sa store na yun andaming mga high quality caps nichicon, rubycon parang andun na lahat kailangan ko hehehe :)
the store name is golden mars in front of deeco sa tingin ko i just need around 2k lahat ng components yun pwera lang yun casing yahoo yahooo!!!
ipon-ipon pa kaunti na lang :)
aysos! update mo kami on how it works out.
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bitin bakasyon ah! ;D anyway, welcome back! ;)
;Dwise choice, fyi i am now at my home in nueva ecija for a 3week vacation, then off to russia again ;D
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;D
i was at golden mars this afternoon, i bought a kg of #36 magnet wire, and for a moment i was stunned to find out that cost of copper has increased from over 400 in february to over 800 today, a 100% increase in just 6 months, tlak about inflation! :'(
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my brother's wholesale supplier can only commit price quote for a day. bummer :(.
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mga sirs i changed my mind medyo mas madali atang gawin yung 3875 kesa sa 3886, balak ko na lang mag ponit to point wiring and maraming nagsasabi na mas maganda yung tunog ng 3875 btw im planning to drive my b&w 303 with this the speaker is rated 89db ata ano po comment nila dito di kaya mag ka problema sa speaker matching?
mga sirs verify ko lang po kung tama ang pag kakaintindi ko dito sa plan na ito. please look at the attached images (i borrowed this from decibel dungeon).
mga sirs eto po yung mga tanong ko:
1) kasi po confused ako sa mga resistor values ng D & F tama po ba yung D na 680/620 ohms na .5watts at yung F naman ehh 20k ohms .25watts?
2) di ko kasi makita sa schematic ng chipamp yung E tama po ba na 4.7uf 50v non polarized cap eto?
3) sa schematic ng chipamp meron 220 ohms kailangan ba eto at saan ko sya dapat ilagay?
salamat po ulet sa mga oras nila :)
eto po yung link ng image sa decibel dungeon
http://myweb.tiscali.co.uk/nuukspot/decdun/gainclonelayout.html
eto yung sa chipamp sa page 3
http://www.chipamp.com/nigc_kit-users_guide.pdf
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muting function lang ang naiba, meron bang available na lm3875 dito?
yung sa chipamp, non-inverting, so yung 220 ohm base stopper resistor, yung sa decibel dungeon, inverting minimized gainclone. if your preamp has an output coupling capacitor, then you can get away without the input cap on your gainclne.
anyway yung 20k at 680/620ohms feedback resistor components yan, 0.25 or 0.5watts can be used. metal film resistors are available from alexan, or maybe golden mars, i haven't asked them though.
the values of these resistors are not that critical, you can even use 22k then 1k... non fatal eka nga, hindi masisira yung chip mo. just use the same values for each channel.
one word of caution, do not use your b&w 303 speakers to test them, these amps do not have speaker protectors, use cheap speakers for testing, and when everything checks out ok then that's the time you can use your bnw speakers.
good luck...
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2ny:
sir meron pong lm3875 sa newport p200+ yung T version yung TF ata p250
sir kaya tama po yung mga values na nailagay ko dun sa D&F? dun kasi me naconfuse.
salamat po ulits
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2ny:
sir meron pong lm3875 sa newport p200+ yung T version yung TF ata p250
sir kaya tama po yung mga values na nailagay ko dun sa D&F? dun kasi me naconfuse.
salamat po ulits
Tama yan. Nakakalito lang kasi yung schematic mo its a non-inverting topology pero yung graphic mo uses inverting. Kung ang plano mo gawin is yung inverting, yung C ay 20K, D ay 680R/620R, and F ay 20K. No need to use the 220R na stopper na nasa schematic.
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2ny:
sir meron pong lm3875 sa newport p200+ yung T version yung TF ata p250
sir kaya tama po yung mga values na nailagay ko dun sa D&F? dun kasi me naconfuse.
salamat po ulits
ok yan, a few years back, nasa 550 yan sa rsonline...
tama si garp, kung ang balak mong gawin ay yung sa decibel dungeon, then 680ohms at 20k, inverted gainclone yan.
as i said these values are not critical, these resistors set the gain of the amp, in this case gain A= 1+20000/680 or ~30, at +/-35 volts rails and 60watts into 8ohms, then an input of about 0.7volts will produce that output.
just ask if there is something you want to be clarified ;D
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kaya pala nakakahilo, magkaiba yun graphic circuit at yun schematic. ;D
better yet, download the LM3875 datasheet from National Bookstore err Semiconductor pala. then build the suggested application circuit which is a non-inverting type.
the datasheet includes a list of the parts and what it does, by trying to understand their use, you will also learn from your project. study the formula for the gain of a non-inverting and inverting amplifier (what Tony gave you), then you can tailor fit your amp's gain setting to suit your needs.
therefore:
study
build
learn
enjoy
;D
cheers
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hahaha sorry sa confusion mga sirs hehehehe kaya pala di talaga mag tugma :D
ngayon ko lang nalaman may inverted gc din pala hehehehe
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yes, the inverted gainclone is very simple and easy to implement using p2p wiring, and yes a TF will be good for your, makes your diy easier...just follow the illustration and your good... ;D
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the inverted gainclone simpler to build ... however take note of the issues of inverted design ... matching impedances, typically higher offset voltage
I have the design of non-inverted which make use of the lowest possible RF/Ri value so that it has the typical impedances and minimum offset voltages. If u r interested, pls give me your email.
If youwill go after tube pre-amp, there have been the design in the inverted GC, which make it simpler.
CIAO
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yes, inverted gainclone have low input impedance, around 600ohms, that is why a buffer is ussually needed if you go that route. you have a lot of choices for buffers...
but as a first try, this is as simple as it can get.
aHobbit, suggest you post your schematic if that is ok with you.
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VBIGC (http://www.customanalogue.com/diytubegainclone/images/JRGC_DIY_T-Net-use.gif) from Joe Rasmussen.
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ahobbit :
sir interested po ako [email protected]
mga sirs isa pang tanong dito kasi sa office andaming surplus na mga ups andaming ei dito hehehehe i'm just curios since yung mga secondaries nila mababa sa requirement ng gc is it possible to have this ei modified in such a way to have a much higher secondaries voltage, naiisip ko lang baka mas mura (chepo hehehe) yung ito kesa mag pa wind ng bago :)
usual na ups na junk dito sa opis ehh mga rated yung mga apc na 300va at meron din ditong junk na 3kva
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You mean you want to use the EI for a tranny with a new winding to suit your gainclone's requirements? Pwede yan basta kasya sa window nun EI. Ask mo si Tony kung ano center leg dapat mo hanapin.
2ny can do that, even with his eyes closed. ;)
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mga sirs isa pang tanong dito kasi sa office andaming surplus na mga ups andaming ei dito hehehehe i'm just curios since yung mga secondaries nila mababa sa requirement ng gc is it possible to have this ei modified in such a way to have a much higher secondaries voltage, naiisip ko lang baka mas mura (chepo hehehe) yung ito kesa mag pa wind ng bago :)
usual na ups na junk dito sa opis ehh mga rated yung mga apc na 300va at meron din ditong junk na 3kva
i suppose that can be done, you may use the 300va one, but mind you, my experience with ups is that the cores are ussually welded, and the windings are auto-transformer wound. but open one up and see for yourself.
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2ny,
dba grinder lang katapat niyan? yan ginamit ko nun nakatyempo ako ng welded EI. pero bad trip talaga pag welded. ;D
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bad trip talaga, lalo na for a newbie....i avoid them if i can.. ;D
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buhayin ko lang po itong thread na ito ;)
nakakuha ako ng samples ng LM4700 and LM3886. maraming info sa 3886 pero parang bihira yung 4700. maganda rin ba yung tunog nito? audiophile-passable ba siya?
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pa'no ba nakakakuha ng samples nyan? :)
buhayin ko lang po itong thread na ito ;)
nakakuha ako ng samples ng LM4700 and LM3886. maraming info sa 3886 pero parang bihira yung 4700. maganda rin ba yung tunog nito? audiophile-passable ba siya?
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i used to get my samples from naldy in hongkong, and also from my friend who works there..afaik, they do not send samples to the philippines..
i have 5 of those chips... ;D
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www.national.com
3 days after request dumating dito via ups
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My first DIY stereo amp is a gainclone using LM1875T chips in kits designed by Silicon Chip (http://Silicon Chip)http://www.siliconchip.com.au/cms/A_103236/article.html. I bought the amp kits from Dick Smiths http://www.dse.com.au/cgi-bin/dse.filereader?45dac9c305a98338273fc0a87f9c0757+EN/catalogpages/CTG0006206/1 (http://www.dse.com.au/cgi-bin/dse.filereader?45dac9c305a98338273fc0a87f9c0757+EN/catalogpages/CTG0006206/1). The power supply kit and the rest of the components/accessories was purchased from Jaycar http://www.jaycar.com.au/productView.asp?ID=KC5347&CATID=25&keywords=&SPECIAL=&form=CAT&ProdCodeOnly=&Keyword1=&Keyword2=&pageNumber=&priceMin=&priceMax=&SUBCATID=557 (http://www.jaycar.com.au/productView.asp?ID=KC5347&CATID=25&keywords=&SPECIAL=&form=CAT&ProdCodeOnly=&Keyword1=&Keyword2=&pageNumber=&priceMin=&priceMax=&SUBCATID=557) The power supply was modified a bit to allow a 18-0-18 Toroids. Soldering/populating the board was the easiest part. Putting the kits in the enclosure and harnessing was the challenge. I completed the project bit by bit in more or less 7 weeks. Initial tests proved that this is a very good sounding gear, a tad better than my modified DSE A2760 amp. The high frequencies are a bit exaggerated(this is due to my room acoustics and maybe my loudspeakers :( I tested the amp using a temporary passive controller (a dual gang 50k linear pot). I found out later that the pot was broken. The attenuation fluctuates and one channel hits 52.6K while the other 46.7K resulting to unbalanced sound coming from the two channel >:( But still the sound is very nice.
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Sirs,
May I ask what should be the budget for a simple GC? The reason is that I have a very old Pioneer reciever (SX 300T) given by my uncle in '83 who used to have a record bar in '76. It has been my amp until I graduated in college. It was working when I kept it but now no sound is coming out. I want it repaired hopefully to last for many more years (in my estimate this receiver is almost 40 yrs old) for sentimental reasons.
I am thinking of 2 options:
1.) Have the amp section replaced by a GC. Is it possible to have a GC designed to use the reciever's own power section as supply. Vintage looking but b/new amp inside.
2.) Have the delaminated PCB replaced (which I think the easiest?), but should there be problematic parts in the future I think it cannot be replaced anymore because the parts are really very old, many parts also do not have values.
Here are some pictures, will surely appreciate your inputs on which option is better and estimated cost, I was thinking of a 2K budget, will this be enough?
(http://i167.photobucket.com/albums/u141/jojo0416/SX%20300T/P1060373a.jpg)
PCB Top Side
(http://i167.photobucket.com/albums/u141/jojo0416/SX%20300T/P1060371a.jpg)
the delapitated/delaminated PCB Back side
(http://i167.photobucket.com/albums/u141/jojo0416/SX%20300T/P1060369a.jpg)
(http://i167.photobucket.com/albums/u141/jojo0416/SX%20300T/P1060366a.jpg)
Thanking you guys in advance. :)
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Kumusta uli,
Here are some photos of the stereo amp.
http://bcol.multiply.com/photos/album/2 (http://bcol.multiply.com/photos/album/2)
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I am thinking of 2 options:
1.) Have the amp section replaced by a GC. Is it possible to have a GC designed to use the reciever's own power section as supply. Vintage looking but b/new amp inside.
2.) Have the delaminated PCB replaced (which I think the easiest?), but should there be problematic parts in the future I think it cannot be replaced anymore because the parts are really very old, many parts also do not have values.
the receiver's own power supply will not do, since it is a single rail evidenced by the two output capacitors, typical of the amps in that era, you will need split rails of +/- to be able to use a gainclone amp. Your amp reminds me of my first cloning adventure in 1977, i cloned a Pioneer SX-770 amp. ;D
Here are some pictures, will surely appreciate your inputs on which option is better and estimated cost, I was thinking of a 2K budget, will this be enough?
if the tuner section still works, maybe it will be worhtwhile to restore this amp using modern-day parts...as to cost, i am not sure, but pm jojod maybe he can give you a better idea... ;D good luck....
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Kumusta uli,
Here are some photos of the stereo amp.
http://bcol.multiply.com/photos/album/2 (http://bcol.multiply.com/photos/album/2)
welcome to the forums....very good job...
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the receiver's own power supply will not do, since it is a single rail evidenced by the two output capacitors, typical of the amps in that era, you will need split rails of +/- to be able to use a gainclone amp. Your amp reminds me of my first cloning adventure in 1977, i cloned a Pioneer SX-770 amp. ;D
if the tuner section still works, maybe it will be worhtwhile to restore this amp using modern-day parts...as to cost, i am not sure, but pm jojod maybe he can give you a better idea... ;D good luck....
Sir Tony,
Thanks for the valued input, yes the tuner is still working, and that was just my plan, if restored I will use it for playing the tuner or still keep it for the future.
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you are welcome... ;D i am off to russia tommorow.... ;D
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welcome to the forums....very good job...
Thank you very much. Enjoy your trip. All the best.
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hello guys, I'm a newbie here and a bit curious with this kind of diy amps. I just want to hear your comment on my budget 2.1 system that i would eventually hook to my pc.
-4pcs of LM3876 bridge two of them so i could have a stereo amp
-a pair of Wharfedale Diamond 9.1 this will driven by the stereo gc amp
-DTX 4.15 sub i don't have a choice for the size of this because the price can't be resist. hehe!
I'll be using my Creative Audigy soundcard's built-in crossover and for the player i'll be using the PowerDVD since it have DolbyDigital processing.
comments po before I push tru .... :) :) :) :) :)
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hello guys, I'm a newbie here and a bit curious with this kind of diy amps. I just want to hear your comment on my budget 2.1 system that i would eventually hook to my pc.
-4pcs of LM3876 bridge two of them so i could have a stereo amp
-a pair of Wharfedale Diamond 9.1 this will driven by the stereo gc amp
-DTX 4.15 sub i don't have a choice for the size of this because the price can't be resist. hehe!
I'll be using my Creative Audigy soundcard's built-in crossover and for the player i'll be using the PowerDVD since it have DolbyDigital processing.
comments po before I push tru .... :) :) :) :) :)
looks good to me except for the bridged amps powering the 9.1s, imho, a single 3875 is already more than enough for the 9.1s, but if you need the extra power and would really like to build a bridge amp then I suggest that you do everything necessary to minimize current sourcing/sinking due to mismatch sections in your bridge amp. an active dc servo per 3876 is not an overkill (at least in my book) since I believe the amp will power your fronts. distortion levels with bridged gc amps is manageable but personally, I would still prefer a straight amp (not a bridged amp) powering my fronts. In other words, if it were mine, I would choose a more powerful amp than resort to bridging amps for more power. Btw, please don't get me wrong, I have nothing against bridged amps, I just don't like what I hear when they are in front. ;D
cheers and good luck to your project 8)
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what if I just bi-amped the speaker sir jojo? would it be a better choice than bridge?
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what if I just bi-amped the speaker sir jojo? would it be a better choice than bridge?
oh yeah, that's the best setup! go go go bi-amp! 8)
don't forget to keep us posted on your project sir...
:)
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i will sir jojo, i think i'll buy the diy kit one or the already made one for reference. but i would definitely diy my next gainclone amp. Thank you ;D ;D
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gud day guyz, i've been browsing for a while about gainclone. i stumbled about chainclone and wonder has anyone have done this already. http://www.platenspeler.com/diy/amps/uk_chainclone_1.html (http://www.platenspeler.com/diy/amps/uk_chainclone_1.html)
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gud day guyz, i've been browsing for a while about gainclone. i stumbled about chainclone and wonder has anyone have done this already. http://www.platenspeler.com/diy/amps/uk_chainclone_1.html (http://www.platenspeler.com/diy/amps/uk_chainclone_1.html)
yup, done it many times... ;D
don't be misled by the "chainclone" term though, this is more known in the gainclone world as bridged (BR100), paralleled (PA100), and bridged/paralleled (BPA200) topology.
I suggest you visit NS and search it's application notes for valuable circuit details.
happy hunting
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i have read some of your post at diy sir jojo and im really impress with ur dyi work amp. Could you please give me a short review of the BPA200 coz i'm a bit amaze with this diy amp. TIA! :)
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i have read some of your post at diy sir jojo and im really impress with ur dyi work amp. Could you please give me a short review of the BPA200 coz i'm a bit amaze with this diy amp. TIA! :)
I still use a bpa200 in one of my sub which I use for HT. It's a powerful amp if you can build it properly, some of the guys have tested it to have an output power close to 400W at 4 ohms loads and a hefty power supply. The only tricky thing (and this is where the fun begins) is how to minimize dc offset and current sinking/sourcing. A mismatch of some sort on one of the branches would either cause that branch to sink current while the other 3 are sourcing it. But that's where NS app notes comes in to help. You can even try using the active dc servo circuits in the app notes, it might be a nightmare to implement but it sure helps a lot.
I decided not to use the bpa200 for the fronts, even with active dc servos. I want my fronts non bridged and non paralleled, but that's just me. :)
Visit NS, I'm sure there's tons of tech info you can use.
Cheers
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i have read some of your post at diy sir jojo and im really impress with ur dyi work amp. Could you please give me a short review of the BPA200 coz i'm a bit amaze with this diy amp. TIA! :)
Stipen, I think I heard you mumbling another group project :D
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@pabili
not really, i'm just want to hear from the generous fellow here who have vast experience with this amp. coz this will be my source of power for our agent x (hopefully) hehehe! ;D btw, sir pabili if you wan't to audition this type of amp I know someone who will be happy to demo them (he's selling this type of amp) to you.
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Just finished doing a gainclone via point to point wiring . I was able to get the lm3886 chip from dihrab in riyadh (im here in ksa).
Sound is good ! ! ! better than my pioneer receiver amp.
I will be modifying it and try to do some tweaks like motorized alps pot / with remote control , upgrading caps and using high speed rectifier etc.
(http://i105.photobucket.com/albums/m211/kandule/005.gif)
(http://i105.photobucket.com/albums/m211/kandule/004.gif)
(http://i105.photobucket.com/albums/m211/kandule/006.gif)
(http://i105.photobucket.com/albums/m211/kandule/007.gif)
Hehehe may uma arbor na nga eh! ! ! hehehe Sabi ko ayoko na ng point to point and ask him to buy the pcb from chipamp.com.
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wow ganda! nice project sir... :)
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wow ganda! nice project sir... :)
Thanks sir, actually i was inspired by all your projects and design, pero itong amps ko talagang tsambahan lng dahil after connecting all the parts, i just closed my eyes and plug the ac . hehehe used to assemble kits from alexan, SWED , TEL and my very favorite amp kits from SMG electronics during college days.
Tanong lng sir, kailangan ko pa ba ng preamp ? im am using a panasonic dvd player for my source, was that enough? tnx ulit.
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Thanks sir, actually i was inspired by all your projects and design, pero itong amps ko talagang tsambahan lng dahil after connecting all the parts, i just closed my eyes and plug the ac . hehehe used to assemble kits from alexan, SWED , TEL and my very favorite amp kits from SMG electronics during college days.
Tanong lng sir, kailangan ko pa ba ng preamp ? im am using a panasonic dvd player for my source, was that enough? tnx ulit.
Hahaha! I used to have that habit of closing my eyes but as I found out, it would be better to keep them open so you can unplug your project faster in case of fireworks... just keep a safe distance or better yet, wear eye protection... ;D ;D ;D sometimes even after doing a triple check of your wirings too much excitement makes humans careless. ;D ;D ;D so practice SAFETY FIRST! 8)
If your source (dvd) can drive your amps then I don't see any reason why you need a separate preamp stage, a volume control (as you planned) will do just fine.
Using a preamp may have it's rewards such as isolation from your source, extra gain (if needed), noise, etc... yes, noise becasue your preamp cannot differentiate between a signal and noise so it may also add unwanted noise in your system if not properly done.
But don't let that stop you! There are tons of info about preamps just waiting for you out there... ;)
:)
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Hahaha! I used to have that habit of closing my eyes but as I found out, it would be better to keep them open so you can unplug your project faster in case of fireworks... just keep a safe distance or better yet, wear eye protection... ;D ;D ;D sometimes even after doing a triple check of your wirings too much excitement makes humans careless. ;D ;D ;D so practice SAFETY FIRST! 8)
If your source (dvd) can drive your amps then I don't see any reason why you need a separate preamp stage, a volume control (as you planned) will do just fine.
Using a preamp may have it's rewards such as isolation from your source, extra gain (if needed), noise, etc... yes, noise becasue your preamp cannot differentiate between a signal and noise so it may also add unwanted noise in your system if not properly done.
But don't let that stop you! There are tons of info about preamps just waiting for you out there... ;)
:)
Hehe thanks again, Two things nga pala that i have noticed is there is an audible humming when i tried to place my ear very very close to the speaker even at a minimum volume and with the source unplugged. I also tried to leave the unit turned on with out any source overnight and i noticed that the heatsink gets warm pero hindi naman sobrang init. Any advice? Thanks...
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Hehe thanks again, Two things nga pala that i have noticed is there is an audible humming when i tried to place my ear very very close to the speaker even at a minimum volume and with the source unplugged. I also tried to leave the unit turned on with out any source overnight and i noticed that the heatsink gets warm pero hindi naman sobrang init. Any advice? Thanks...
First check your wirings, then make sure all joints are "mechanically sound" before they were even soldered. This is the first rule in p2p soldering, many diyers out there fail in this regard and so with a little practice I'm sure you'll have smart joints in no time.
Secondly, check your grounding, gainclones are notoriously susceptible to hum with poor grounding. Star grounding has been the norm and has numerous documentations over the net in case you would like to give your amp a grounding make-over.
Lastly, study grounding schemes, learn how it affects your precious signal. These will help you make your amps/preamps super quiet - believe me. ;D
My secret in "hum management" is... "become the ground", I know it's funny but try to put yourself in the ground's shoes and you'll understand why it hums. ;D
Enjoy
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Two things nga pala that i have noticed is there is an audible humming when i tried to place my ear very very close to the speaker even at a minimum volume and with the source unplugged. I also tried to leave the unit turned on with out any source overnight and i noticed that the heatsink gets warm pero hindi naman sobrang init. Any advice? Thanks...
hi,
if you have to put your ears very close to the speakers, then it should not be a cause for alarm, if you want you can try relocating the negative return lead of the speakers to the transformer center tap to see if that improves things.
about the warm sinks, i wouldn't worry about that too. this chip has enough protection built-in so that if all connections are good, then it should function flawlessly..
congratulations.... ;D
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hi,
if you have to put your ears very close to the speakers, then it should not be a cause for alarm, if you want you can try relocating the negative return lead of the speakers to the transformer center tap to see if that improves things.
about the warm sinks, i wouldn't worry about that too. this chip has enough protection built-in so that if all connections are good, then it should function flawlessly..
congratulations.... ;D
Thats what i did sir (placing my ear touching the speaker). About warming, i read somewhere over the net that these chip consumed 2.5 watts of current when idle, could it be the reason why the warming? My pcb order from chipamp.com is on the way, later i can compare my ptp design with their product.
Thanks sir tonyt and sir jojo ...
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Thats what i did sir (placing my ear touching the speaker). About warming, i read somewhere over the net that these chip consumed 2.5 watts of current when idle, could it be the reason why the warming? My pcb order from chipamp.com is on the way, later i can compare my ptp design with their product.
Thanks sir tonyt and sir jojo ...
yes, that is called quiscient dissipation, if you like you can install the pentiun3 heatsinks in vertical manner, that way it is 100% effective, you may even retain the fans... ;D
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yes, that is called quiscient dissipation, if you like you can install the pentiun3 heatsinks in vertical manner, that way it is 100% effective, you may even retain the fans... ;D
Thanks for the reply sir. Nga pala sir sinukat ko yung output voltage ng dalawang amp, it reads 18 mv at 60 mv. I understand na dapat eh less than 100 mv pero yung 60 mv dc offset voltage diba masyadong mataas? pano ko ba aatakehin to? :) thanks in advance....
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Thanks for the reply sir. Nga pala sir sinukat ko yung output voltage ng dalawang amp, it reads 18 mv at 60 mv. I understand na dapat eh less than 100 mv pero yung 60 mv dc offset voltage diba masyadong mataas? pano ko ba aatakehin to? :) thanks in advance....
18mV and 60mV is fine, anything below 100mV is okey, you don't have to worry,nor do anything, otherwise, magiging complicated yung amp mo.... ;D
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18mV and 60mV is fine, anything below 100mV is okey, you don't have to worry,nor do anything, otherwise, magiging complicated yung amp mo.... ;D
:) Ok sir, hehe i guess i'll stop and start to enjoy the music and the wine . Now tell me about your leach amp , ;)
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Now tell me about your leach amp
working as an OFW,i really can not find the time to complete this amp, i have everything except for the chassis, i guess having a chassis made to accomodate my conrad heatsinks takes more the a month, and i only go on leave 3 weeks. so it is a work in progress.
main boards:
(http://i20.photobucket.com/albums/b201/tecson/leach%20amp/Cimg0292.jpg)
(http://i20.photobucket.com/albums/b201/tecson/leach%20amp/Cimg0293.jpg)
(http://i20.photobucket.com/albums/b201/tecson/leach%20amp/Cimg0361.jpg)
power supply:
(http://i20.photobucket.com/albums/b201/tecson/leach%20amp/Cimg0354.jpg)
(http://i20.photobucket.com/albums/b201/tecson/leach%20amp/CIMG0512.jpg)
(http://i20.photobucket.com/albums/b201/tecson/leach%20amp/CIMG0514.jpg)
(http://i20.photobucket.com/albums/b201/tecson/leach%20amp/CIMG0522.jpg)
(http://i20.photobucket.com/albums/b201/tecson/leach%20amp/CIMG0519.jpg)
soft start and +/-15volt supply:
(http://i20.photobucket.com/albums/b201/tecson/leach%20amp/Cimg0367.jpg)
(http://i20.photobucket.com/albums/b201/tecson/leach%20amp/Cimg0369.jpg)
power traffo:
(http://i20.photobucket.com/albums/b201/tecson/leach%20amp/CIMG0517.jpg)
(http://i20.photobucket.com/albums/b201/tecson/leach%20amp/CIMG0516.jpg)
input /output components:
(http://i20.photobucket.com/albums/b201/tecson/leach%20amp/CIMG0394.jpg)
(http://i20.photobucket.com/albums/b201/tecson/leach%20amp/CIMG0396.jpg)
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working as an OFW,i really can not find the time to complete this amp, i have everything except for the chassis, i guess having a chassis made to accomodate my conrad heatsinks takes more the a month, and i only go on leave 3 weeks. so it is a work in progress.
main boards:
(http://i20.photobucket.com/albums/b201/tecson/leach%20amp/Cimg0292.jpg)
(http://i20.photobucket.com/albums/b201/tecson/leach%20amp/Cimg0293.jpg)
(http://i20.photobucket.com/albums/b201/tecson/leach%20amp/Cimg0361.jpg)
power supply:
(http://i20.photobucket.com/albums/b201/tecson/leach%20amp/Cimg0354.jpg)
(http://i20.photobucket.com/albums/b201/tecson/leach%20amp/CIMG0512.jpg)
(http://i20.photobucket.com/albums/b201/tecson/leach%20amp/CIMG0514.jpg)
(http://i20.photobucket.com/albums/b201/tecson/leach%20amp/CIMG0522.jpg)
(http://i20.photobucket.com/albums/b201/tecson/leach%20amp/CIMG0519.jpg)
soft start and +/-15volt supply:
(http://i20.photobucket.com/albums/b201/tecson/leach%20amp/Cimg0367.jpg)
(http://i20.photobucket.com/albums/b201/tecson/leach%20amp/Cimg0369.jpg)
power traffo:
(http://i20.photobucket.com/albums/b201/tecson/leach%20amp/CIMG0517.jpg)
(http://i20.photobucket.com/albums/b201/tecson/leach%20amp/CIMG0516.jpg)
input /output components:
(http://i20.photobucket.com/albums/b201/tecson/leach%20amp/CIMG0394.jpg)
(http://i20.photobucket.com/albums/b201/tecson/leach%20amp/CIMG0396.jpg)
wow ! ! ! heheheh nanliit yung gainclone amp ko dyan ah ! ! ! Sir ilang ampere and volt yan tranny mo? yung pcb ng amp design mo ba? grabeeh tanong ko pero di ubra dito sa riyadh yan hehehe baka hulihin ako ng mga mutawa heheheeh..
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ilang ampere and volt yan tranny mo?
78volts center tapped, the traffo has a primary rating of 500va, it is my own design and i diy'ed it myself. core is EI-150, 1.5 inch center leg stacked about 3.5inches.
the pcb's are from a group buy at www.diyaudio.com..... ;D
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i haven't followed the thread really closely but i'm quite interested in building my own gain clone amp. would anyone know if this can be modified for car use? :)
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i haven't followed the thread really closely but i'm quite interested in building my own gain clone amp. would anyone know if this can be modified for car use? :)
you need +/-30volts or so, a car battery is only 12volts, so you will need an smps psu to get these voltages...
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78volts center tapped, the traffo has a primary rating of 500va, it is my own design and i diy'ed it myself. core is EI-150, 1.5 inch center leg stacked about 3.5inches.
the pcb's are from a group buy at www.diyaudio.com..... ;D
Sir,
Isa ka ba sa naka avail nung initial group buy nila? Ito ba yung 6 Transistor?
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tony,
thanks for the reply. is a smps psu the same as a step-up transformer? i mean, i could have a 12vdc transformer made to go up that high, right? is it the same as the psu's of car amplifiers?
thanks!
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Sir,
Isa ka ba sa naka avail nung initial group buy nila? Ito ba yung 6 Transistor?
yup, i did....there is another thread and we hope to initiate another group buy, this time for leach super amps...
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tony,
thanks for the reply. is a smps psu the same as a step-up transformer? i mean, i could have a 12vdc transformer made to go up that high, right? is it the same as the psu's of car amplifiers?
thanks!
you need to be able to convert 12volt dc of your car to +/- 35 volts dc needed by the gainclones..
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CAOHYDE,
Check out these schematics from ESPhttp://sound.westhost.com/project89.htm (http://sound.westhost.com/project89.htm) and from DJQUANhttp://djquan.angelcities.com/smps.html (http://djquan.angelcities.com/smps.html)
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thanks b-col for the links. i forgot about it when i saw his post in KAC. maybe i could PM him or something about this. :)
thanks again!
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ano po ba ang latest regarding sa availability and prices ng LM3875? LM3876? meron na po ba neto sa raon?
saan na ba madali makakakuha neto ngayon?
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ano po ba ang latest regarding sa availability and prices ng LM3875? LM3876? meron na po ba neto sa raon?
saan na ba madali makakakuha neto ngayon?
meron yta sa Newport sa Raon. check mo sa pricelist nila.
http://newportelec.com/ic_l.html
LM3875 270.00
LM3876TF 250.00
LM3886T 320.00
LM3886TF 265.00
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thanks sir ferds sa info!! :D :D kelangan ko kc 6 pieces neto para masimulan ko na triamp system ko..
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sir would you happen to know kung orig ba yung mga chips na benebenta dyan sa raon? medyo kaduda kasi dami lumalabas na fake lagi pa sa raon binabagsak...
meron yta sa Newport sa Raon. check mo sa pricelist nila.
http://newportelec.com/ic_l.html
LM3875 270.00
LM3876TF 250.00
LM3886T 320.00
LM3886TF 265.00
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diy'ers...
asking lang kung me na publish na 2x LM3886 as bridge w/ PCB layout.
Pa post naman, at kung sino merong ready na PCB na, willing to pay. hehehehe
janni
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sir would you happen to know kung orig ba yung mga chips na benebenta dyan sa raon? medyo kaduda kasi dami lumalabas na fake lagi pa sa raon binabagsak...
buhayin lang natin tong thread na to..i want to build this project din...available pa ba to sa Raon?
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hey I didnt know that there was a topic pala dito sa pdvd about gaincard/clones. Mukang almost 2yrs ago na itong thread but it has 40+ pages din ah ::)
Such a coincidence that this thread resurrected as Jojod & I recently talked about this project with enthusiasm ;D
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hey I didnt know that there was a topic pala dito sa pdvd about gaincard/clones. Mukang almost 2yrs ago na itong thread but it has 40+ pages din ah ::)
Such a coincidence that this thread resurrected as Jojod & I recently talked about this project with enthusiasm ;D
ito ba yung mga maliliit na 100 watts per channel?
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ito ba yung mga maliliit na 100 watts per channel?
3 yata ang power versions - 25watts, 50watts & 75watts
Parang ganito brader:
http://www.sakurasystems.com/products/47amp.html
http://www.6moons.com/audioreviews/47labs5/gaincard.html
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how time flies! i started this thread 6 years ago, and got jojod to join pdvd when i met him at diyaudio....and the rest is history...jojod is now a legend..... ;D
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ito ba yung mga maliliit na 100 watts per channel?
i think this is the technology behind marco pilyo's 56 watt amp5.
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how time flies! i started this thread 6 years ago, and got jojod to join pdvd when i met him at diyaudio....and the rest is history...jojod is now a legend..... ;D
time flies indeed tony! if not for your invite I wouldn't have known and bought a Kebao dvd player... ;D ;D ;D and met a lot of friends! 8)
no legend here, just the same old student of electronics... ;D
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i think this is the technology behind marco pilyo's 56 watt amp5.
Yes sir, ito nga mismo ang AMP ni Sir Pilyo. I've seen an almost similar design din kasi using this chip in ESP website and according to the designer this amp performs very good daw. Buti nalang meron din tayong mga designer's dito so we could try din.
Up ko lang sir, saan ba available mga chips na to? meron ba to sa Raon?
Jeff29jeff2002
(Jason)
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read back a little bit lang sir may naka post po na shop not sure lang kung meron pa actually... you can also try online ordering... hth
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@jeff
current price sa newport.
LM3875 270.00
LM3876TF 250.00
LM3886T 320.00
LM3886TF 340.00
BTW i have LM4780 kit "68W Stereo". If you want just pm me.
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meron akong nabili LM3875 sa farnell P310.00 each pero for sure d mawawalan ng mga chips na to sa raon.
kelangan ko pa nga 4 pcs neto para sa tri amp project ko. kumpleto na components/parts ko ng 3way
active crossover pati pcb layout wala lang talaga time mag fabricate pcb.
i will be using this gainclone amps since this is simple to build sa tingin ko. meron na din akong pcb layout
but again kulang time sa paggawa.. haaayyy.. kelan kaya matatapos project ko na to?
nakakatamad kasing magfabricate ng pcb.. tsk.
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Hi, if you dislike pcb's, you can also do point-to-point wiring, just like we did during the tube amp days.... ;)
check out the postings of peter daniel at the diyaudio website to give you some idea.... 8)
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haha tama sir tony kaso gandahan mo lang at i finalize mo kundi, kapag tumagal babaklasin mo nanaman yan haha, at medyo maasiwa ka hehe.
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@jeff
current price sa newport.
LM3875 270.00
LM3876TF 250.00
LM3886T 320.00
LM3886TF 340.00
BTW i have LM4780 kit "68W Stereo". If you want just pm me.
@t68kv
Thanks, I'll try to check it this weekend.
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yan nga point to point nga sana yang unang consideration ko.pero sayang naman kasi ginastusan ko na gusto mko medyo maganda na kalabasan. tyagain ko na lang makabuo ng pcb. pcb na lang naman kulang ko
then lalarga na ko ng tuloytuloy sa paggawa. masarap lang kasi talaga mag diy. nakikita mo unti unti nabubuo yung project mo.. sana lang magan da kalabasan hehe..
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masarap lang kasi talaga mag diy. nakikita mo unti unti nabubuo yung project mo.. sana lang magan da kalabasan hehe..
yes, the feeling of pride and satisfaction can not be eqauted with pesos and cantavos.... :D :)
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There is no counterpart to the satisfaction you got if your projects works as it should be. Because of pinoydvd I started doing diy electronics projects again. After joining pinoydvd my first project was leach amp then the super leach amp. My gainclone was never finished. I already have the pcb with all the parts in it except for the ic. I am looking forward of using lm3886tf. Last weekend I build my own subwoofer filter and was was very satisfied with the outcome. While cory’s funeral is going on I am busy building a “Tula Preamp and Tone Control Kit with 1RU 19” enclosure”. Just yesterday I received the “Tula 150 watts per channel stereo amp kit (power supply and enclosure included)". This are gifts (pasalubong) from a thai friend. He says that Tula is the best kit manufacturer in Thailand. Maybe true because the kits I bought before in Bangkok doesn’t come close to this. I am just not happy that kits like this is not available here. I'll work on the amplifier for the next two weekends.
By the way i already set aside my DBX 120a subwoofer synthesizer and Dual 31 Band graphic equalizer to give for my diy subwoofer filter and tula preamp.
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@adrianm, if you need help, just ask away..... ;)
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hi guys,,... may alam ba kayo na local shop na nagbebenta ng precision resistors??? <1%
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sa alexan meron.
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chief t68kv!! :) kamusta?
hinahanap ko sana better than 1% precision eh
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sir would you happen to know kung orig ba yung mga chips na benebenta dyan sa raon? medyo kaduda kasi dami lumalabas na fake lagi pa sa raon binabagsak...
Guys, Up ko lang tong inquiry na to. I bought a chip just yesterday and tried it. Gumana naman but the sound is not that good. I am suspecting na bka hindi authentic nabili ko na chip sa Raon. Or do you happen to know where could we buy guranteed authentic gainclone chips?
Jeff29jeff2002
( jason )
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HI,
if you can post the schematic you used, then we can tell, or pictures perhaps...
can you describe your set-up please? let us not jump to conclusions just as yet... ;)
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The diagram is the same as shown in its data sheet.
http://www.datasheetcatalog.org/datasheet2/f/0xkohcyduuewz1wt3jh7uir9f03y.pdf
Jeff
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JEF,
Diagram is one thing, but how you actually wired your amp is another...that is why some pictures would help, also your psu, how did you implement it, your grounding, this is critical too...
about fakes, afaik, only discretes are faked, but who knows? ;D
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Hi sir Tony,
I've figured it out now.It was not the IC. It was the least I expect to cause a problem. It was my speaker which I use.... ;D ;D ;D . I might have broken it during my first testing thats why its causing some audible distortions at low level listening ( Charge to experience nalang..UUU ) ::) . I am now using the other channel speaker and its singing very well. Yup, the sound is indeed good. What a relief. I didn't think this small chip is capable of damaging a 120w max local woofer..UUU
Simple lang po set-up ko..from FM Tuner / DVD player going directly to AMP with added volume control lang in between. I might send pictures to you for further improvments. Maybe later, after I finished it placing in its casing.
Thanks for the inputs.. :D
Regards,
Jason
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hi, jeff, what happened there was that you had large dc off-set at the speakers, that's why it burned out, insulation resistance between adjacent turns on the speakers' voice coils drops so low to cause shorts between turns....did you smell something? ;D
it happened to me also, i used my 15inch westwell woofer for testing way back in '85, well we all have a share of this "magic smoke".... :'(
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hehe nandito ka pala chief ryan :)
Mukang matindi yang project mo ah? naghahanap ka na ng mas matinding accuracy, ayos yan. Ebay maybe? hehe
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hi, jeff, what happened there was that you had large dc off-set at the speakers, that's why it burned out, insulation resistance between adjacent turns on the speakers' voice coils drops so low to cause shorts between turns....did you smell something? ;D
it happened to me also, i used my 15inch westwell woofer for testing way back in '85, well we all have a share of this "magic smoke".... :'(
Hi sir Tony,
Hindi naman sya nag-smoke. Maybe some internal parts just loosened up thats why some distorted sound is audible in low level listening. Parang may sumayad na sa loob. Pero hindi na sya audible at high volume..yun nga lang mejo noticeable na yung difference in sound compared to a good speaker.
Anyway sir, as the saying goes... You will not learn until you will make mistakes... :).
Jeff
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hi, jeff, what happened there was that you had large dc off-set at the speakers, that's why it burned out, insulation resistance between adjacent turns on the speakers' voice coils drops so low to cause shorts between turns....did you smell something? ;D
it happened to me also, i used my 15inch westwell woofer for testing way back in '85, well we all have a share of this "magic smoke".... :'(
yan ang kaluluwa ng mga electronics equipment. kaya pag nakita mong lumabas yan patay na equipment mo. ;D
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naku pareng jeff kahit hindi sya masunog kapag may presence ng malaki dc sa output ng amp mo ganyan talaga mangyayari dyan, ganito ang senaryo kaya hindi nasunog yung speaker, hindi ganun ka laki yung dc para masunog nya yung 120w woofer mo, pero kung normal operation, malabong masira or masunog nya yung speaker.
Check mo using multimeter, add mo rin ng dummy resistor para makita mo kapag may load.
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naku pareng jeff kahit hindi sya masunog kapag may presence ng malaki dc sa output ng amp mo ganyan talaga mangyayari dyan, ganito ang senaryo kaya hindi nasunog yung speaker, hindi ganun ka laki yung dc para masunog nya yung 120w woofer mo, pero kung normal operation, malabong masira or masunog nya yung speaker.
Check mo using multimeter, add mo rin ng dummy resistor para makita mo kapag may load.
Hi t68kv,
Thanks for the tip...as of now ok na po yung project. Its sounding very well. As in my earlier post, it was just caused by some unsoldered parts during my initial checking which might have caused some DC output to the speaker...But now, its all sounding well..And now Im working on placing it on its final casing to complete my 2.1 Local DIY Amp set-up.
Thanks for the inputs guys...and more power to all of us.. ;)
Jeff29jeff2002
(Jason)
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To prevent costly speaker accidents, always use a cheap, non-capacitive 8 ohm speaker (preferably with a series 1A fuse) when testing new amps or when doing repairs. Those small full range types will serve you well.
Rule #1 is check everything thrice
Rule #2 is check your psu and make sure it's within limits before connecting your amp
Rule #3 is check biasing (for tubes and discrete ss), skip for chipamps
Rule #4 is checking DC offset with either a dummy load or a cheap speaker
FYI, oscillations can also destroy your speakers so keep your wires compartmentalized and for goodness sake please check your grounding. Safety First!
There's no voodoo in soldering, like sex, it is best mastered with practice. But please never try doing both at the same time!
You can make up other Rules as you go along and grow your experience in building amps, but know these basics by heart now and you should survive many years unscathed.
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I just plan to build the low powered one, might just use a simpler circuit but still add a buffer if possible. The tricky part here is what design for the power supply will I use :) I've got data sheets for lm3886, lm3875 and lm1875, might just do the one in the lm1875's data sheet though sinc eI have 4 l1875's at hand already :)
Hi,
Try the capacitance multiplier, I have used this type in all of my projects, especially my JLH, also in my gainclone using TA8216H toshiba chips, there is a very big diffrence from conventional ps, (by the way dont forget to practice single point grounding or star grounding especially in gainclones!) download the diagram at ESP sound pages. (Rod Elliots Site)
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To prevent costly speaker accidents, always use a cheap, non-capacitive 8 ohm speaker (preferably with a series 1A fuse) when testing new amps or when doing repairs. Those small full range types will serve you well.
Rule #1 is check everything thrice
Rule #2 is check your psu and make sure it's within limits before connecting your amp
Rule #3 is check biasing (for tubes and discrete ss), skip for chipamps
Rule #4 is checking DC offset with either a dummy load or a cheap speaker
FYI, oscillations can also destroy your speakers so keep your wires compartmentalized and for goodness sake please check your grounding. Safety First!
There's no voodoo in soldering, like sex, it is best mastered with practice. But please never try doing both at the same time!
You can make up other Rules as you go along and grow your experience in building amps, but know these basics by heart now and you should survive many years unscathed.
Very Good tip..Thanks sir Jojo.
Jeff29jeff2002
(Jason)
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my gainclones kagagawa lang.. :)
(http://img198.imageshack.us/img198/3602/cimg5933g.jpg)
(http://img11.imageshack.us/img11/6212/cimg5946r.jpg)
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Hi,
good job! ;D are those parts, (terminal blocks and fuse holders) available in RAON? matagal na rin akong hindi napasyal doon.... ;D
spin electronics in madaluyong sells FR4 boards, they are very nice to use...better than phenolics... ;D
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Thanks Sir Tony.. LM3875 and polyester caps are from FARNELL medyo mahirap kasi makakita ng polyester
caps especially 1% tolerance locally.sinabay ko lang yung dalawang LM3875 pero available naman siguro sa raon IC na to. kelangan ko pa nga 4 pcs. and dito na lang sa raon siguro ko hahanap.
Terminal blocks are from ALEXAN, fuse holder from DEECO maganda lang tingnan kasi me takip pa kaya ko binili
mas mura pa. the rest ng components local lang from alexan and deeco din.
Masaya naman ako sa kinalabasan. ok na output power para sakin. light listening lang naman ako. saka tri amp system tong project ko so six amp would driving two 3 way speaker eh malakas na to..
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Thanks Sir Tony.. LM3875 and polyester caps are from FARNELL medyo mahirap kasi makakita ng polyester
caps especially 1% tolerance locally.sinabay ko lang yung dalawang LM3875 pero available naman siguro sa raon IC na to. kelangan ko pa nga 4 pcs. and dito na lang sa raon siguro ko hahanap.
Terminal blocks are from ALEXAN, fuse holder from DEECO maganda lang tingnan kasi me takip pa kaya ko binili
mas mura pa. the rest ng components local lang from alexan and deeco din.
Masaya naman ako sa kinalabasan. ok na output power para sakin. light listening lang naman ako. saka tri amp system tong project ko so six amp would driving two 3 way speaker eh malakas na to..
Sir kikongkiko,
sir I like your idea of making a tri-amp using gainclones...Naisip ko rin yan after hearing the performance of gainclones. Ask ko lang sir, what would you be using for its active cross-over? ive seen one in alexan but haven't tried it...
jeff
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just to get started, the one sold by alexan as a kit is a good way to go.... ;D
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Sir jeff,
D ko pa nakita yung kit ng alexan.pero sabi nga ni sir tony good start yun. kung alam ko lang na meron na nun baka naconsider ko yun.
Anyway meron naman na ko nagawa na Electronic crossover. madali lang naman kung complete na yung parts
mo fabrication is kayangkaya na natin.. lalo na pag hobbyist ka. ;D. there are lots of info and literature mababasa sa net basa lang ng basa mayamaya gagawa ka na. haha.
eto nga pala yung electronic crossover na gnawa ko.
(http://img140.imageshack.us/img140/1011/cimg5219kiko.jpg)
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just to get started, the one sold by alexan as a kit is a good way to go.... ;D
Thanks sir Tony for the tip...
Sir jeff,
D ko pa nakita yung kit ng alexan.pero sabi nga ni sir tony good start yun. kung alam ko lang na meron na nun baka naconsider ko yun.
Anyway meron naman na ko nagawa na Electronic crossover. madali lang naman kung complete na yung parts
mo fabrication is kayangkaya na natin.. lalo na pag hobbyist ka. ;D. there are lots of info and literature mababasa sa net basa lang ng basa mayamaya gagawa ka na. haha.
eto nga pala yung electronic crossover na gnawa ko.
(http://img140.imageshack.us/img140/1011/cimg5219kiko.jpg)
Nice project sir kikongkiko... How does the tri-amp gainclone sound sir? Im expecting it to sound very clear...tama ba?
Jeff
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Actually sir d ko pa natest electronic crossover na to with my gainclone. kasi isa palang yung finish na gainclone kulang pa kasi ko ng apat na na LM3875 chip for the other two unit.
Initially ang testing ko ng crossover eh using yung yamaha receiver RXV440 and sakura387a para lang mabuo yung tri-amp and matest ko nga.I was amazed sa separation and linis nung tunog using pa lang yung dalawang amp nato.sulit ang pagod panahon at gastos ang masasabi ko.
yung isang gainclone natest ko naman sa ordinary na 3way speaker na passive xover and malinis nga tunog
as what gainclone specially etong mga NS chip are known.
I also assume na magiging maganda tambalan ng electronic xover na to and gainclone.Today i'll go to RAON
to buy the needed 4 chips para mabuo na ang triamp and finally matest ko na ang buong project na to.
Sana lang makakita ko ng 3875..mahaba ang bakasyon ngayon and hopefully macomplete ko nato.
Give you feedback sir pag natest ko ng buo na. by the way san ba me murang LM3875 sa RAON?
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May nabanggit dito sa thread na store sa Raon selling the chip at 250. I have bought mine in Raon at 235. I forgot the name of the store. Some store sells it at 300 plus..kaya kunting ikot2x lang sa ibang stores withhin Raon.
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nakabili na ko sir. mahal 360 isa. tatamad na kasi ko magikot. binili ko na rin para matapos na ko.
ongoing pagagawa ko ngayon. :)
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my gainclones kagagawa lang.. :)
(http://img198.imageshack.us/img198/3602/cimg5933g.jpg)
(http://img11.imageshack.us/img11/6212/cimg5946r.jpg)
Fantastic Sir!
Congrats for the very nice layout.
Do you use a PCB software
:)
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Yes Sir.. Pad2pad pcb software. natapos ko na yung 6 channel amp na to for tri amping. d ko lang alam kung pano ko icase to. temporarily ni layout ko muna sa isang base na kahoy. skeleton muna para mapakinabangan
na. more or less ganito kalalabasan..
(http://img18.imageshack.us/img18/771/dsc01857j.jpg/[img]
[img]http://img130.imageshack.us/img130/5474/dsc01859p.jpg)
[img]http://img97.imageshack.us/img97/5699/dsc01861y.jpg/[img]
i know the electronic crossover sitting on top of the heatsink is wrong because it will absorb the heat that will be dissipated when this amp is operated at high volume level. pero temporary lang naman until i find a suitable casing. the preamp and crossover will be put in same enclosure seperate from the enclosure of the power amp.
wala pang bolt and nut para ma fix at ma wire na to. and magamit na. although napatunog ko na to.
and im very happy sa sound.. ;D ;D ;D
worth the effort.. and gastos.. :'(
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hi kikongkiko, ganda ng layout mo sobrang linis tignan, :)
eto kabaligtaran ng kalinisan ng layout mo, hehe
(http://i300.photobucket.com/albums/nn28/ryan750_mhz/DSC00161.jpg)
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Hi Sir Ryan,
Thanks for sharing your lay-out. Dont worry, hindi ka nag-iisa sa lay-out na ganyan. I think mine is even worst.. ;D ;D ;D
Kakatuwa lang and very satisfying hobby natin if mag-function na gawa natin.. Kaya More Power to you sir..
Jeff
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Kakatuwa lang and very satisfying hobby natin if mag-function na gawa natin.. Kaya More Power to you sir..
yup, this is a feeling that non-diy'ers can not hope to experience......we learn from our mistakes......good job!
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next project aayusin ko na lay out, hehe parallel lm3886 naman para sa sub, :)
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Gumaya na din ako sa inyo. Just wanted to revive my college days electronics hobby..medyo nagalawang na. My Gainclone stereo Amp (LM3876) with Philips TDA 1524a tone control.
(http://[URL=http://img265.imageshack.us/i/lm3876.jpg/][IMG]http://img265.imageshack.us/img265/3458/lm3876.th.jpg)[/URL]
(http://img265.imageshack.us/img265/9084/tonecontrol.th.jpg) (http://img265.imageshack.us/i/tonecontrol.jpg/)
(http://img265.imageshack.us/img265/8994/amptonectrl.th.jpg) (http://img265.imageshack.us/i/amptonectrl.jpg/)
(http://img265.imageshack.us/img265/7190/ampfronttop.th.jpg) (http://img265.imageshack.us/i/ampfronttop.jpg/)
(http://img97.imageshack.us/img97/4484/amprear.th.jpg) (http://img97.imageshack.us/i/amprear.jpg/)
(http://img69.imageshack.us/img69/2986/tonectrlamp.th.jpg) (http://img69.imageshack.us/i/tonectrlamp.jpg/)
[/img]
Since this portable Amp is quite heavy at 4.8kg, I decided to put a sturdy steel handle on top and put some flower design. This amp will be used by my daughter for her ipod and laptop audio playback. I tested this with my Samsung, NIVS and Qisheng hi-fi speakers and it was really clean, crisp and clear. I also tested this amp 8hrs non-stop with the JBL MRX515 and wow, it can really drive the 15” speakers with ease. Overall conclusion, I was really satisfied on the outcome of this project. However, I need to add speaker output delay/protector since I can hear the thump sound as I power up.
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@catrow23 ,
welcome to the forums and great to see your works.....i know there are lots of pinoy talents out there....
so to the mods....can i petition for a DIY section here? thanks..
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Thanks Sir Tony, I was just inspired by all you great guys from pinoy dvd..just from reading your forums and comments I really learned a lot. Im trying to polish up cause its been more than 10yrs since I got hold of the soldering iron again. Ang hirap pala, nangalawang na nga. Thats why I started again to buy tools for my hobby nakaka miss din. If I have the time, I will go to Shenzhen with friends buy some spare parts and start making projects again. C U around.. :)
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yes... DIY section.. ;D agree..
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@catrow23 ,
welcome to the forums and great to see your works.....i know there are lots of pinoy talents out there....
so to the mods....can i petition for a DIY section here? thanks..
Yes, I SECOND the Petition...
-
Gumaya na din ako sa inyo. Just wanted to revive my college days electronics hobby..medyo nagalawang na. My Gainclone stereo Amp (LM3876) with Philips TDA 1524a tone control.
(http://[URL=http://img265.imageshack.us/i/lm3876.jpg/][IMG]http://img265.imageshack.us/img265/3458/lm3876.th.jpg)[/URL]
(http://img265.imageshack.us/img265/9084/tonecontrol.th.jpg) (http://img265.imageshack.us/i/tonecontrol.jpg/)
(http://img265.imageshack.us/img265/8994/amptonectrl.th.jpg) (http://img265.imageshack.us/i/amptonectrl.jpg/)
(http://img265.imageshack.us/img265/7190/ampfronttop.th.jpg) (http://img265.imageshack.us/i/ampfronttop.jpg/)
(http://img97.imageshack.us/img97/4484/amprear.th.jpg) (http://img97.imageshack.us/i/amprear.jpg/)
(http://img69.imageshack.us/img69/2986/tonectrlamp.th.jpg) (http://img69.imageshack.us/i/tonectrlamp.jpg/)
[/img]
Since this portable Amp is quite heavy at 4.8kg, I decided to put a sturdy steel handle on top and put some flower design. This amp will be used by my daughter for her ipod and laptop audio playback. I tested this with my Samsung, NIVS and Qisheng hi-fi speakers and it was really clean, crisp and clear. I also tested this amp 8hrs non-stop with the JBL MRX515 and wow, it can really drive the 15” speakers with ease. Overall conclusion, I was really satisfied on the outcome of this project. However, I need to add speaker output delay/protector since I can hear the thump sound as I power up.
@ catrow23,
Nice job Dude!
;)
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Thanks Dude, need to add some speaker delay . I will try to work out on the relay and circuit you gave me..c u around :) Sir Tony will move this forum to DIY section..ciao
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Thanks Dude, need to add some speaker delay . I will try to work out on the relay and circuit you gave me..c u around :) Sir Tony will move this forum to DIY section..ciao
Yep dude, ;)
exactly, this should go along with the DIYers as most on this thread posts their DIY GC amp.
Good luck to your additional protection circuit.
By the way, whenever you need deeper understanding and assistance to these audio stuff, there are lots of experts and audio gurus like Sir TonyT, Master J, s2kov, Edrel,... who are always willing to spend some of their time to share their knowledge.
I usually throw some Qs to them mostly during confussions. ;D
Para hindi naman OT, here's my experimental 3875TF:
(http://i226.photobucket.com/albums/dd136/joelkine/IMGP0898.jpg)
(http://i226.photobucket.com/albums/dd136/joelkine/IMGP0958.jpg)
;)
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Hi Tube Pro,
OK yang heatsink mo, panalo! Sana may makita ako d2 nyan! :)
-
hi andy,
punta ka sa third floor ng sim lim square, dun sa mga nagrerepair ng pc's makakabile ka ng hsf ng procs, pwede gamitin yan...
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Hi Tube Pro,
OK yang heatsink mo, panalo! Sana may makita ako d2 nyan! :)
Sir s2kov,
opo, sir TonyT is right. Makakakuha ka ng mga ganyan hs sa mga old computers, usually sa mga Pentium 3 galing yan.
I think this one I have is from a HP Vectra desktop computer. Passive cooling kaya mahaba un fin. unfortunately, wala na rin po akong makitang kapatid nyan d2, maraming almost same pero iba pa rin size at looks, may built-in fan pa.
Kaya plan ko, gawa ako ng 5 channels, yang isa gawin kong pang center channel. :D
para d OT, ito po sya, wala talaga provision for fan, free air convection cooling sya:
(http://i226.photobucket.com/albums/dd136/joelkine/IMGP0892.jpg)
(http://i226.photobucket.com/albums/dd136/joelkine/IMGP0891.jpg)
(http://i226.photobucket.com/albums/dd136/joelkine/IMGP0899.jpg)
(http://i226.photobucket.com/albums/dd136/joelkine/IMGP0908.jpg)
hoping na makita ko pa kahit isa sa kanyang mga kapatid d2 sa Macau, para stereo na lang ang gagawin ko... ;D
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hi andy,
punta ka sa third floor ng sim lim square, dun sa mga nagrerepair ng pc's makakabile ka ng hsf ng procs, pwede gamitin yan...
Hello Sir TonyT,
I heard nanjan ka po sa Pinas for a vacation. Sa dec26 naman po sked ng flight ko jan. ;)
excited na nga din at na-miss ko na ang Raon. ;D
By the way sir, I have this confussion I wanna ask from you.
matagal ko ng pinagiisipan na gumamit ng switching power supply for these Gainclone amps.
+/-35v is fine for an 8-ohm load and higher power output.
+/- 29v if gc will be loaded with a 4-ohm speakers.
I saw many high power but compact switching power supplies in China, not in Shenzhen yet, and they are very light weight (off course no huge pt), can i also use this to power the GCs? or has anybody tried this already? how's the sound quality then?
To think that all of our Crown amps, the XTi series, we use for events/parties and small gigs, (but not for arena concerts, we use Meyer sound), like the XTi 4000 is no longer using torroidals but switching supplies.
Below pics and specs are those supplies I'm referring to...
(145 watts series, [email protected])
(201 watts series, 35V@6A)
will use two units as it's just a single output, one for the possitive rail and the other for the negative:
145W
(http://i226.photobucket.com/albums/dd136/joelkine/Models.jpg)
(http://i226.photobucket.com/albums/dd136/joelkine/Specs.jpg)
201W
(http://i226.photobucket.com/albums/dd136/joelkine/Models201w.jpg)
(http://i226.photobucket.com/albums/dd136/joelkine/Specs201w.jpg)
:)
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hi joel,
if i were you, i'd chose 145 watts series, [email protected] to be on the safe side....you will have a hard time to tell the difference between rails of 35 and 27 volts......
have a safe flight, and advanced merry Christmas and prosperous new year....
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hi joel,
if i were you, i'd chose 145 watts series, [email protected] to be on the safe side....you will have a hard time to tell the difference between rails of 35 and 27 volts......
have a safe flight, and advanced merry Christmas and prosperous new year....
Thanks Much sir TonyT for the nice suggestion. should be better as it is more cheap too. ;D
Salamat sir. Advanced Merry Christmas din and to ALL PDVD folks! :D
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thanks, try ko punta this weekend! :)
hi andy,
punta ka sa third floor ng sim lim square, dun sa mga nagrerepair ng pc's makakabile ka ng hsf ng procs, pwede gamitin yan...
-
chassis na lng kulang! :)
Sir s2kov,
opo, sir TonyT is right. Makakakuha ka ng mga ganyan hs sa mga old computers, usually sa mga Pentium 3 galing yan.
I think this one I have is from a HP Vectra desktop computer. Passive cooling kaya mahaba un fin. unfortunately, wala na rin po akong makitang kapatid nyan d2, maraming almost same pero iba pa rin size at looks, may built-in fan pa.
Kaya plan ko, gawa ako ng 5 channels, yang isa gawin kong pang center channel. :D
para d OT, ito po sya, wala talaga provision for fan, free air convection cooling sya:
(http://i226.photobucket.com/albums/dd136/joelkine/IMGP0892.jpg)
(http://i226.photobucket.com/albums/dd136/joelkine/IMGP0891.jpg)
(http://i226.photobucket.com/albums/dd136/joelkine/IMGP0899.jpg)
(http://i226.photobucket.com/albums/dd136/joelkine/IMGP0908.jpg)
hoping na makita ko pa kahit isa sa kanyang mga kapatid d2 sa Macau, para stereo na lang ang gagawin ko... ;D
-
thanks, try ko punta this weekend! :)
andy,
try to get those P4 socket 478 hsf's, they cost around 250 here used...maybe you can get them for about the same price there.....pwede naman tawaran.... ;D
-
chassis na lng kulang! :)
oo nga sir, wala pa ko chassis kc wala pang final layout. ;D
also, kabibili ko lang din ng transformer kahapon and other parts. Mejo nagpa sobra for spare kung sipagin uli.
ito na nga pala ung ibang makakasama nya sa chassis.
24v-0-24v (200w)
(http://i226.photobucket.com/albums/dd136/joelkine/IMGP1004.jpg)
Filter Caps (Nippon Chemi-Con)
(http://i226.photobucket.com/albums/dd136/joelkine/IMGP1006.jpg)
3875 & 3886
(http://i226.photobucket.com/albums/dd136/joelkine/IMGP1008.jpg)
Which Heatsink is better for 2 GCs?
1:
(http://i226.photobucket.com/albums/dd136/joelkine/IMGP1016.jpg)
(http://i226.photobucket.com/albums/dd136/joelkine/IMGP1015.jpg)
2:
(http://i226.photobucket.com/albums/dd136/joelkine/IMGP1018.jpg)
(http://i226.photobucket.com/albums/dd136/joelkine/IMGP1020.jpg)
:)
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high joel,
magkano yung torroid traffo? saka yung yung 6800/100volt nichicon caps, i need 4 of those...
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high joel,
magkano yung torroid traffo? saka yung yung 6800/100volt nichicon caps, i need 4 of those...
hi Sir TonyT,
Sir, hindi nichicon ung binili ko, Nippon Chemi-Con (105'c) ung nasa picture. (un din ba un?) ;D
un lang available doon sa CatTai Shuhai. D pa kc kmi natuloy sa Shenzhen, baka sa January or Feb 2010 kc nag renew ng bluecard. Cgurado mas mura pa rin doon.
Anyways, ito po ung converted price nung mga items in Php:
Electrolytic Caps (Nippon Chemi-Con):
6,800uF/63V = P 86.80 (I have 6 pcs, gagamitin ko ung 4 pcs, so 2 pcs lang spare)
6,800uF/100v = P 130.20 (I have 4 pcs, pwedeng d ko muna gamitin, next year pa naman for my MOSFET DIY amp)
10,000uF/100v = P 162.75 (I have 4 pcs, baka gamitin ko ung 2 pcs)
Gainclone ICs:
TDA7294 = P 205.28 (bought 2 pcs, nagamit ko isa sa AR sub, 1 spare)
LM3875TF = P 280.35 (I have 2 pcs)
LM3886TF = P 300.30 (I have 8 pcs, baka 2pcs lang muna gamitin ko)
ung Torroidal traffo:
24v-0-24v (200W) = P 1,512.00
if you need those caps sir, tell me lang po, dalhin ko pag uwi ko ng Dec 26.
:)
-
afaik, parehas lang dahil sa logo....can i have the 4pcs. 6,800ufd/100v caps? thanks....
-
meron ako nakita nito sa raon last week.
24.5v-0-24.5v + 9.5v (200W) = P 600
gamit daw sa isang sakura amp :)
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meron ako nakita nito sa raon last week.
24.5v-0-24.5v + 9.5v (200W) = P 600
gamit daw sa isang sakura amp :)
saan sa raon? thanks...
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afaik, parehas lang dahil sa logo....can i have the 4pcs. 6,800ufd/100v caps? thanks....
Ok sir Tony,
those caps (6,800uF/100v 4pcs) are yours.
pki pm po contacts.
Dec 26 flight ko, Dec27 12:30am arrival
Dec27-28, Tanauan Batangas (outing) :D
Dec 29 or 30 (baka punta ako ng Raon) ;)
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hi joel, you can reach me thru.....09167382574...thanks..
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@joel,
got your sms, text mo ko pag pupunta ka ng raon, give 2 hours leadtime, matraffic kasi... ;D
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@joel,
got your sms, text mo ko pag pupunta ka ng raon, give 2 hours leadtime, matraffic kasi... ;D
Hi Sir Tony,,
Saan ka ba manggagaling if ever?
Baka naman along the way ka lang, pwede na kitang dalawin ng makapamasko na rin ninong Tony.... hahahaha... :D
'wag mo na pong ibalot, isobre nyo nlang... ;D
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Hi Sir Tony,,
Saan ka ba manggagaling if ever?
Baka naman along the way ka lang, pwede na kitang dalawin ng makapamasko na rin ninong Tony.... hahahaha... :D
'wag mo na pong ibalot, isobre nyo nlang... ;D
pasig....
okey isosobre ko na............ ;D
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@tonyt
hehe, hindi ko maalala yung exact name ng store pero sa may tapat lang sya ng eleshop, dun sa mga store dun :)
Planning to get one next year :)
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@tonyt
hehe, hindi ko maalala yung exact name ng store pero sa may tapat lang sya ng eleshop, dun sa mga store dun :)
Planning to get one next year :)
hi, nakakuha ka na? marami ba yan o isang piraso lang?
-
meron ako nakita nito sa raon last week.
24.5v-0-24.5v + 9.5v (200W) = P 600
gamit daw sa isang sakura amp :)
anong model kaya ng sakura? so ang rails ng sakura +/- 35 votls, parang gainclones ano? 40 watts per channel.... ;D
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Hi Sir TonyT,
Just arrived here in Macau. Back to work na on Saturday. :D
Nice meeting you master Tony... :)
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same here...thank you very much... :)
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@TonyT
hahah! malabong gagamit ng gainclone chipamps ang sakura. Mas malaki parin kikitain nila kung transistor gagamitin nila hehe. Pura transistorized lahat ang sakura na nakikita ko. Sa electown lang ako nakakita ng chips at lm1875 pa na gamit sa surround at center.
Saktong sakto nga para sa chipamp yung trafo eh, bili sana ako kaso bitin ata yun para sa lm4780, ano sa tingin mo sir tony.
-
tingin ko kakayanin ang lm4870.....
-
Natry ko na kasi gumamit ng split 25v 6amp na IE sa lm4780, although kaya nya na talaga yung heavy bass pero mukang mas ok parin siguro kapag 8amp ang gamitin ko.
Tama ba computation ko sir tonyt?
25vx2=50x6amp = 300VA?
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Natry ko na kasi gumamit ng split 25v 6amp na IE sa lm4780, although kaya nya na talaga yung heavy bass pero mukang mas ok parin siguro kapag 8amp ang gamitin ko.
Tama ba computation ko sir tonyt?
25vx2=50x6amp = 300VA?
yup, mas mabigat ang traffo mo mas malakas ang bass mo, dagdagan mo rin yung filter caps.. ;D
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yup 22kuf gamit ko :D hehe
So kung 200W or VA lang yung toroid na ginamit sa sakura, mas sufficient parin yung setup ko ngayon na 6amp, bibili sana ako nung toroid hehe.
-
pwede ka naman magparallel ng 2 toroids, pwede pag patungin yun 2 para mas malakas ang psu mo...
-
pwede ka naman magparallel ng 2 toroids, pwede pag patungin yun 2 para mas malakas ang psu mo...
sir assuming the two torroids don't have the exact same voltages, say 1 or 2 volts difference, can we still connect in parallel?
-
sir assuming the two torroids don't have the exact same voltages, say 1 or 2 volts difference, can we still connect in parallel?
not adviseable, magkakaroon ng circulating currents, dapat talaga identical...
-
so best practice parin yung single trafo lang.
-
mga guys na try nyo na ba mag diy ng class D amps. try nyo gawin ang TDA7482 ng STmicroelectronics. magulat kayo sa performance nito. and the chips is mura lang, from newport at sa tapat ng alexan ung bilihan ng schematic diagram. follow nyo lang datasheet. malaki ang kaibahan sa LM. sa power supply pa lang malaki na kaibahan, kahit 1A lang na transformer kaya sya.
-
Na try ko na mag diy ng Class D pero puro smd devices and Tripath chips... Have you actually tried that SGS chip already? Kamusta naman po ang tunog?
Being a Class D with an efficiency of 87% I assume malamig po siya ano?
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hi guyz,
I am newbie here in pdvd, and interested s gainclone amp.ano ang pwede nyong isuggest n starter kit?kaya kayang idrive nito ung speaker ko kc i'am not happy s tunog pagdating s music when using receiver? I have a pair of polkaudio Lsi7 4 ohms and 88db sensitivity.
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very nice thread :)
it's been a long time since i did this amp (way back in highschool pa yata) and i'm still a newbie;D
I've sold my pc speakers and bought my very first BS (a-audio), but wala pa ako amp so i decided to build one as a temporary amp habang nag iipon for a sakura amp...so i decided to visit raon and scout for spare parts and other components and went home with all the parts i need which costs below 300pesos excluding psu:)
heres my 8-watt/ channel lm383t:
done etching (oldschool), placement/ soldering of components
(http://i192.photobucket.com/albums/z21/blackmoly_photos/Pic4071-1.jpg)
test fit:
(http://i192.photobucket.com/albums/z21/blackmoly_photos/Pic4073-1.jpg)
semi finished:
(http://i192.photobucket.com/albums/z21/blackmoly_photos/Pic4077.jpg)
(http://i192.photobucket.com/albums/z21/blackmoly_photos/Pic4076.jpg)
i'm using my 12vdc regulated psu rated @ 6A btw..so far i'm happy with it's sq :)
i plan to change it's electrolytic caps with jap brands and hoping to see or hear some improvements.
that's about it for now, no led indicator, no vol control... :)
hopefully summertime i can build another LM amp but this time much better in terms of power, sq, and most importantly a good casing and wire management (not temporary) ;D
backread mode- page 1
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Nice and simple circuit sir. Linis pagkagawa. :)
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Can anyone help me with my gainclone? Pasensya na po, newbie ako dito sa PDVD and don't know where to post
I built this 6 channel LM1875 kaso 3 channels are not doing well. Two of them nawa-wala wala yung sound then the other one have no sound at all. I've star-grounded the circuits and double checked the connections, seems OK naman. Also, the chips get really hot. Am using 17V 6A nga pala as power supply. Here're pics of my project:
(http://img641.imageshack.us/img641/8132/date357.th.jpg) (http://img641.imageshack.us/i/date357.jpg/)
(http://img31.imageshack.us/img31/5696/date356.th.jpg) (http://img31.imageshack.us/i/date356.jpg/)
(http://img405.imageshack.us/img405/9243/date355.th.jpg) (http://img405.imageshack.us/i/date355.jpg/)
(http://img543.imageshack.us/img543/8169/date353.th.jpg) (http://img543.imageshack.us/i/date353.jpg/)
TIA po and more power sa PDVD!!!
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Kindly post the schematic you used (if any).
1. What are the DC output offset measurements you got from all the channels?
2. Check that you have completely isolated the metal tabs of the chips from the heatsink. De-burr your holes to prevent breaching your insulator. From what I see in the pics, you are not using any nylon bushings on your hold down bolts.
3. 17V only? So this is a single supply version?
-
Kindly post the schematic you used (if any).
1. What are the DC output offset measurements you got from all the channels?
2. Check that you have completely isolated the metal tabs of the chips from the heatsink. De-burr your holes to prevent breaching your insulator. From what I see in the pics, you are not using any nylon bushings on your hold down bolts.
3. 17V only? So this is a single supply version?
1. What are the DC output offset measurements you got from all the channels?
This I have to check with a reliable multi-tester. Mine is a cheap China-made tester kasi.
2. Check that you have completely isolated the metal tabs of the chips from the heatsink. De-burr your holes to prevent breaching your insulator. From what I see in the pics, you are not using any nylon bushings on your hold down bolts.
Sir I did use nylon bushings, di lang masyadong kita sa pics. And based on my "cheap, China-Made" ;D multi-tester walang contact between the tabs and the heatsink.
3. 17V only? So this is a single supply version?
Sorry po, +- 17v@6A so rail voltage is around 23-24
Here're the schematics that I used nga pala, bale dalawang klase. Medyo mahabang istorya po kung ba't dalwang schematic ginamit ko ;D
http://www.euronet.nl/~mgw/diy/amps/gainclown_lm1875_inverted.gif
at eto po yung isa pa:
http://schematics.circuitdiagram.net/viewer.php?id=bwy1259118639a.JPG
-
1. What are the DC output offset measurements you got from all the channels?
This I have to check with a reliable multi-tester. Mine is a cheap China-made tester kasi.
2. Check that you have completely isolated the metal tabs of the chips from the heatsink. De-burr your holes to prevent breaching your insulator. From what I see in the pics, you are not using any nylon bushings on your hold down bolts.
Sir I did use nylon bushings, di lang masyadong kita sa pics. And based on my "cheap, China-Made" ;D multi-tester walang contact between the tabs and the heatsink.
3. 17V only? So this is a single supply version?
Sorry po, +- 17v@6A so rail voltage is around 23-24
Here're the schematics that I used nga pala, bale dalawang klase. Medyo mahabang istorya po kung ba't dalwang schematic ginamit ko ;D
http://www.euronet.nl/~mgw/diy/amps/gainclown_lm1875_inverted.gif
at eto po yung isa pa:
http://schematics.circuitdiagram.net/viewer.php?id=bwy1259118639a.JPG
1. You don't need a Japan-made tester to do that naman... Get a fresh 1.5V AA battery and calibrate your meter if it's an analog or if it's a digital then see if it's within acceptable tolerance. Your reading at the outputs should be better than +/-0.1V (a reading of +/-0.001V is ideal and possible).
2. Ok good, you must have used those clear ones which is not visible in the resolution of your pics. Anyway, did you ground (return to star ground) your heat sink?
3. Alright it's symmetrical supplies. Make sure about your connections on the V+ and V- pins and that you truly supply voltage in there.
So your using an inverted and a non-inverted topology, nothing wrong there except you must be careful when using them in a multi-channel fashion for they might cancel signals especially in the low frequencies.
Do you test with a dummy load (resistive) or a speaker connected at the output? I ask because one of the schematics you posted uses a zobel network while the other doesn't. This network helps eliminate porous oscillations from occurring when the amp is connected to a capacitive load.
Lastly, test each amp one at a time. You can connect in series a 100 ohm 2 watt resistor in between the V+ and the V- pins, without any load and without any problems there shouldn't be much of a voltage drop across this resistors. A huge voltage drop across this resistors means the amp is drawing too much current and unless it's at full power, it shouldn't be the case.
Let me know po your readings, I'm here all week.
Good luck,
Jojo
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Sir Jojo thanks for the tips! really useful.
Checklists:
1. DC offset of all channel is 0.1???, though diskumpyado pa din ako kasi may hum.
2. Haven't tried measuring the amp's current draw at zero/no load
Have re-checked the solders. Turns out, one channel have a broken connection sa input. so okay na lahat. Problem ko na lang is that with only 2 channels, umiinit na sya which, I think is also the reason why pawala-wala ang sound. The thermal protection is kicking in. plus an annoying hum.
Oh well, re-check na naman. Lamog na ata perfboard ko kaka-bali-baligtad. ;D
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Sir Jojo thanks for the tips! really useful.
Checklists:
1. DC offset of all channel is 0.1???, though diskumpyado pa din ako kasi may hum.
2. Haven't tried measuring the amp's current draw at zero/no load
Have re-checked the solders. Turns out, one channel have a broken connection sa input. so okay na lahat. Problem ko na lang is that with only 2 channels, umiinit na sya which, I think is also the reason why pawala-wala ang sound. The thermal protection is kicking in. plus an annoying hum.
Oh well, re-check na naman. Lamog na ata perfboard ko kaka-bali-baligtad. ;D
No problem sir, feed-forward na lang.
1. 0.1V DC offset is the absolute max and indicates something is still not where it should be. Check, and re-check, then check again. It's right in front of you, it's just evading your attention.
2. Please do that with no load. For the 1875, idle current should be around 50mA to 70mA typical with 100mA as maximum with an 8 ohms non-capacitive load and Pout=0W.
Try this, with your speaker connected to the amp's output, short the inputs to ground. If the hum disappears then you have a grounding problem. If the hum is still there then there's an error in your implementation.
Hayaan mo lang siyang malamog, importante may natutunan ka sir. ;)
Good luck
Jojo
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Sir Jojo thanks for the tips! really useful.
Checklists:
1. DC offset of all channel is 0.1???, though diskumpyado pa din ako kasi may hum.
2. Haven't tried measuring the amp's current draw at zero/no load
Have re-checked the solders. Turns out, one channel have a broken connection sa input. so okay na lahat. Problem ko na lang is that with only 2 channels, umiinit na sya which, I think is also the reason why pawala-wala ang sound. The thermal protection is kicking in. plus an annoying hum.
Oh well, re-check na naman. Lamog na ata perfboard ko kaka-bali-baligtad. ;D
Good day sir,
may I share my unsolicited advice? :) I have used LM1875T before, they are sensitive when it comes to proper grounding, so make sure you implement "star " or single point grounding. Alexan has a better schematics(i think), so check mo yung diagram nila regarding LM1875, as one of the electrolytics suggested is non polar. If you use polarized the connect it in series + to + , the - leads are connected to the ckt.
If you really want to totally eliminate hum, implement capacitance multiplier in the p/s section, visit Rod Elliot's sound pages for schematics (Ellliots Sound Pages).
normal sa isang DIY'er ang kalas kabit, through that way you honed your project to suit you personal prefferences.
Happy Gaincloning ;)
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Good day sir,
may I share my unsolicited advice? :) I have used LM1875T before, they are sensitive when it comes to proper grounding, so make sure you implement "star " or single point grounding. Alexan has a better schematics(i think), so check mo yung diagram nila regarding LM1875, as one of the electrolytics suggested is non polar. If you use polarized the connect it in series + to + , the - leads are connected to the ckt.
If you really want to totally eliminate hum, implement capacitance multiplier in the p/s section, visit Rod Elliot's sound pages for schematics (Ellliots Sound Pages).
normal sa isang DIY'er ang kalas kabit, through that way you honed your project to suit you personal prefferences.
Happy Gaincloning ;)
Thanks for the advice Sir, really appreciated, but I think I'd still stick with my current schematic/s, I've made this work before, without hum and sounding perfect, kaso nang in-incorporate ko na yung anim na amp sa isang perfboard, saka lang nagka-problema. Perpekin ko muna to, heheheh!!! though this one's tempting: http://www.headphoneamp.co.kr/ftp/sijosae/Gallery/Gain%20Clone/Gainclone-1a.jpg ::)
BTW, kanina po, as I was troubleshooting, ti-nry ko i-connect yung ground lead ng speak sa output ng isa pang amp na walang input signal, tumunog po sya, same SQ as if you've connected the spk's ground lead to the amp's ground(?). Could this mean po kaya na grounded nga to the output side yung amp ko?
Sir Jo, I've tried connecting the input to the ground, may hum pa din po. Will double check the PSU, baka andun ang problema.
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There are several ways to tackle grounding issues:
1. your power transformer must have a center tap that is exactly equal in voltage, this is done by winding the secondary in bifilliar manner, this exactly locates your transformer center tap.
2. or you can use double bridges, one for the positive and one for the negative rails. you must have dual 12 volt secondaries, you can even use two transformers....
3. your speaker return lines should go to your main filter caps meeting point. i would prefer that grounding to chassis once you get one be done at this point.
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Sir Jo, I've tried connecting the input to the ground, may hum pa din po. Will double check the PSU, baka andun ang problema.
Ah madali lang yan, parang alam ko na nga kung saan galing yun hum hehehe... Check the ground return path of your input and feedback loop - make absolutely sure that no huge currents are returned via this path. Better yet, give your signal ground it's very own "expressway" path to ground.
There are several ways to tackle grounding issues:
1. your power transformer must have a center tap that is exactly equal in voltage, this is done by winding the secondary in bifilliar manner, this exactly locates your transformer center tap.
2. or you can use double bridges, one for the positive and one for the negative rails. you must have dual 12 volt secondaries, you can even use two transformers....
3. your speaker return lines should go to your main filter caps meeting point. i would prefer that grounding to chassis once you get one be done at this point.
1. You can check this right away through the amps output because an imbalance will be translated into a huge DC output offset.
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Pahabol...
I can't help but notice it but the schematics you posted both uses very high resistance in the feedback loop, something like 10K and 200K IIRC, I don't practice that because it promotes DC voltage to be present at the non-inverting input (if it's inverting) or inverting input (if it's non-inverting) because of the input currents. This in turn biases the input and in the end you get a high output DC offset.
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good day sa lahat :)
I've already bought parts for my lm3875 proj. pero di ko pa na assemble.
question lang po about sa psu, mas ok po ba pag "snubberized" yung rectifiers?
and also ano po recommended na value ng filtering caps? I already have 2pcs. 10000uf/ 50v.
i have a 48v ct (EI) traffo @ 6A btw but i'm planning to replace it with a torroidal one. thanks! :)
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good day sa lahat :)
I've already bought parts for my lm3875 proj. pero di ko pa na assemble.
question lang po about sa psu, mas ok po ba pag "snubberized" yung rectifiers?
and also ano po recommended na value ng filtering caps? I already have 2pcs. 10000uf/ 50v.
i have a 48v ct (EI) traffo @ 6A btw but i'm planning to replace it with a torroidal one. thanks! :)
i suggest that you build it first without the snubber, then when your gainclone is working, try the snubbers and see if you like it....
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i suggest that you build it first without the snubber, then when your gainclone is working, try the snubbers and see if you like it....
a ok so there is a noticeable difference right? thanks sir tony! Will do assembly probably on monday...
I'll try to post pictures later on :)
another question: where (store in raon?) can I buy torroidal traffo?
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I think Eleshop may have torroids.
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I think Eleshop may have torroids.
thanks bro :)
some pics of my proj.
hopefully ma assemble na, tinatapos lang exams and proj sa school ;D
layout
(http://i192.photobucket.com/albums/z21/blackmoly_photos/DSCF1041.jpg)
other parts
(http://i192.photobucket.com/albums/z21/blackmoly_photos/DSCF1100-1.jpg)
(http://i192.photobucket.com/albums/z21/blackmoly_photos/DSCF1077.jpg)
case
(http://i192.photobucket.com/albums/z21/blackmoly_photos/DSCF1103-1.jpg)
(http://i192.photobucket.com/albums/z21/blackmoly_photos/DSCF1097.jpg)
still needs backpanel case modification and drilling holes for front panel and mounting screws.
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Pahabol...
I can't help but notice it but the schematics you posted both uses very high resistance in the feedback loop, something like 10K and 200K IIRC, I don't practice that because it promotes DC voltage to be present at the non-inverting input (if it's inverting) or inverting input (if it's non-inverting) because of the input currents. This in turn biases the input and in the end you get a high output DC offset.
Whew! Almost 2 weeks and a crispy lm1875 have passed and I still have the same heating and humming problem.
I've replaced the 180k/200k and 10k/22k resistors with 22k and 1k. My Lead ears doesn't seem to notice any difference. Hum and heat is still there.
Here's the alarming part: I took these voltage readings of the trafo and they are alarming:
1. Transformer output: -+17V, ayus!!!
2. After Bridge (Single bridge, one probe on to the ground/centertap): +-46V!!! :o
3. After Smoothing Capacitors (2x2200uf, 50V): +-46V!!! :o
At first I thought I had a faulty DMM, then tried it with my AMM, readings after bridge and caps are still the same at +-46V.
Actions done:
1. Isolated the trafo from the amp: still +-46V
2. Center Tap to in-between smoothing caps: still +-46V
I guess this is where the Hum and excessive heat is coming from as rails are almost near my caps' 50v/63v rating.
Anyone care to help me on my trafo problem? Please? :'(
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your rails are scary high.....i wouldn't use more than +/-24volts.....that explains ost of your problems..
look here:http://www.national.com/ds/LM/LM1875.pdf (http://www.national.com/ds/LM/LM1875.pdf)
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your rails are scary high.....i wouldn't use more than +/-24volts.....that explains ost of your problems..
look here:http://www.national.com/ds/LM/LM1875.pdf (http://www.national.com/ds/LM/LM1875.pdf)
Oo nga po e. Supposedly, 17-0-17v lang yun, rectified, 24v-0-24v lang dapat, di ko makuhha kung bakit dumoble halos to 46v-0-46v. Di kaya sira yung smoothing caps?
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do not connect your chips yet, work on the psu till you get those rails right...you may have miswired something...it kinda hard to troubleshoot in from of a monitor....but the key is get those voltages right first..
you have to be meticulously slow, be patient, if you can get someone to look at your work, maybe he will find something you may have missed...
ganyan talaga mag-diy, hindi lahat gagana ng tama sa unang power up... ;)
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Oo nga po e. Supposedly, 17-0-17v lang yun, rectified, 24v-0-24v lang dapat, di ko makuhha kung bakit dumoble halos to 46v-0-46v. Di kaya sira yung smoothing caps?
malamang yung bridge diode
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malamang yung bridge diode
Bought another bridge diode, 35A, yung square. Ganun pa din ang voltage readings. ???
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mag post ka ng picture sir para makita namin...
17Vac-0-17Vac should be around +/-24Vdc unloaded...
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mag post ka ng picture sir para makita namin...
17Vac-0-17Vac should be around +/-24Vdc unloaded...
Yes Sir.Yun nga din ang expected ko kaso AMM shows a different value. More of like doubled/series'd yung leads. After bridge, +-32 to 34VDC (17x2?), then after Smoothing caps na 2x2200uf/50V, lampas 50V ang reading.
BTW here're some pics:
(http://img94.imageshack.us/img94/9082/170176a.th.jpg) (http://img94.imageshack.us/i/170176a.jpg/)
Trafo: Tamagawa (di kaya MALIgawa?) ;D 17-0-17VAC@6A
Bridge Diode: 35A@???V
(http://img132.imageshack.us/img132/7046/1617vac.th.jpg) (http://img132.imageshack.us/i/1617vac.jpg/)
AC Readings @ 17VAC
(http://img689.imageshack.us/img689/3755/1517vac.th.jpg) (http://img689.imageshack.us/i/1517vac.jpg/)
AC Readings @ 17VAC
(http://img693.imageshack.us/img693/7347/34vafterbridgeammsettoa.th.jpg) (http://img693.imageshack.us/i/34vafterbridgeammsettoa.jpg/)
+34VDC after bridge, TAKE NOTE: AMM set to read AC reading!?! normal ba yun? (2x17???)
(http://img718.imageshack.us/img718/724/3334vdc.th.jpg) (http://img718.imageshack.us/i/3334vdc.jpg/)
+32 to 34VDC after bridge, TAKE NOTE: AMM set to read DC reading. (2x17???)
(http://img52.imageshack.us/img52/7347/34vafterbridgeammsettoa.th.jpg) (http://img52.imageshack.us/i/34vafterbridgeammsettoa.jpg/)
-34VDC after bridge, TAKE NOTE: AMM set to read DC reading!?! normal ba yun? (2x17???)
(http://img191.imageshack.us/img191/724/3334vdc.th.jpg) (http://img191.imageshack.us/i/3334vdc.jpg/)
-32 to 34VDC after bridge, TAKE NOTE: AMM set to read DC reading. (2x17???)
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pwede mo ipost yung schematics ng psu mo?
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pwede mo ipost yung schematics ng psu mo?
Ganito po. Plus 2x2200uf/50v smoothing caps. . . .And it states that rail voltage is x1.414 of secondary, turns out, mine's x2. ;D
http://myweb.tiscali.co.uk/nuukspot/decdun/gainclone_psu.html
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Try ko kaya to? Kaso additional expense na naman for smoothing caps. . . . Haaaay. yung HK145 na lang kaya sa trade section. . . ::)
http://sound.westhost.com/project04.htm
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Yes Sir.Yun nga din ang expected ko kaso AMM shows a different value. More of like doubled/series'd yung leads. After bridge, +-32 to 34VDC (17x2?), then after Smoothing caps na 2x2200uf/50V, lampas 50V ang reading.
BTW here're some pics:
(http://img94.imageshack.us/img94/9082/170176a.th.jpg) (http://img94.imageshack.us/i/170176a.jpg/)
Trafo: Tamagawa (di kaya MALIgawa?) ;D 17-0-17VAC@6A
Bridge Diode: 35A@???V
(http://img132.imageshack.us/img132/7046/1617vac.th.jpg) (http://img132.imageshack.us/i/1617vac.jpg/)
AC Readings @ 17VAC
(http://img689.imageshack.us/img689/3755/1517vac.th.jpg) (http://img689.imageshack.us/i/1517vac.jpg/)
AC Readings @ 17VAC
(http://img693.imageshack.us/img693/7347/34vafterbridgeammsettoa.th.jpg) (http://img693.imageshack.us/i/34vafterbridgeammsettoa.jpg/)
+34VDC after bridge, TAKE NOTE: AMM set to read AC reading!?! normal ba yun? (2x17???)
(http://img718.imageshack.us/img718/724/3334vdc.th.jpg) (http://img718.imageshack.us/i/3334vdc.jpg/)
+32 to 34VDC after bridge, TAKE NOTE: AMM set to read DC reading. (2x17???)
(http://img52.imageshack.us/img52/7347/34vafterbridgeammsettoa.th.jpg) (http://img52.imageshack.us/i/34vafterbridgeammsettoa.jpg/)
-34VDC after bridge, TAKE NOTE: AMM set to read DC reading!?! normal ba yun? (2x17???)
(http://img191.imageshack.us/img191/724/3334vdc.th.jpg) (http://img191.imageshack.us/i/3334vdc.jpg/)
-32 to 34VDC after bridge, TAKE NOTE: AMM set to read DC reading. (2x17???)
wag mo na galawin yan setup mo sir. kabit mo sir yun filter caps, then take readings ulit (set mo lang sa 50VDC yun AMM mo).
may question lang ako.
1. Without anything connected to your tranny (br diode disconnected), 17-0-17 pa din reading mo?
2. Get a 1.5V AA battery (hiram ka lang sa remote ng tv, dvd, etc) then measure it's DC voltage para lang sure tayo diyan sa AMM mo hehehe...
Try ko kaya to? Kaso additional expense na naman for smoothing caps. . . . Haaaay. yung HK145 na lang kaya sa trade section. . . ::)
http://sound.westhost.com/project04.htm
wag ka agad mawalan ng pag asa, wala ka mararating niyan pag umayaw ka agad. online naman ako, andyan pa si Tony oh, kayang kaya natin yan. ;D
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wag mo na galawin yan setup mo sir. kabit mo sir yun filter caps, then take readings ulit (set mo lang sa 50VDC yun AMM mo).
may question lang ako.
1. Without anything connected to your tranny (br diode disconnected), 17-0-17 pa din reading mo?
2. Get a 1.5V AA battery (hiram ka lang sa remote ng tv, dvd, etc) then measure it's DC voltage para lang sure tayo diyan sa AMM mo hehehe...
wag ka agad mawalan ng pag asa, wala ka mararating niyan pag umayaw ka agad. online naman ako, andyan pa si Tony oh, kayang kaya natin yan. ;D
Thanks Sir Jojo n Tony!!! Sige pagtulungan natin to. Gusto ko din talagang matuto. Actually meron na akong 2pcs/sets ng Yuanjing lm3886 GC from Ebay, ayaw ko lang simulang gang di ko natatapos tong LM1875 na to.
BTW fresh batts were not around so I tried measuring my orig PSP charger, 5V 2000ma. Dead on 5V, saktong sakto. Current/amperage, di mabasa, nasunog ata last time I checked, unfused kase. :P
BTW merong Universal Laptop SMPS sa CDRKing, x2 would give around [email protected]. watchathink? Shortcutin ko na? ;D
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Thanks Sir Jojo n Tony!!! Sige pagtulungan natin to. Gusto ko din talagang matuto. Actually meron na akong 2pcs/sets ng Yuanjing lm3886 GC from Ebay, ayaw ko lang simulang gang di ko natatapos tong LM1875 na to.
BTW fresh batts were not around so I tried measuring my orig PSP charger, 5V 2000ma. Dead on 5V, saktong sakto. Current/amperage, di mabasa, nasunog ata last time I checked, unfused kase. :P
BTW merong Universal Laptop SMPS sa CDRKing, x2 would give around [email protected]. watchathink? Shortcutin ko na? ;D
Ayun ok naman pala AMM. ;)
Shortcut? Wag naman, kung sa akin yan hindi ako titigil (baka nga hindi ako makatulog) until I find out why it is acting like that. ;D
Pero kung gusto mo mag smps gagana din naman yun kaya lang can you live with the fact that you never found out why your power supply is not working? ;D
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check mo connections from tranny CT to ground, pag open yan ang bridge mo will become a voltage doubler.
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check mo connections from tranny CT to ground, pag open yan ang bridge mo will become a voltage doubler.
korek, but look at the pics, he's measuring wrt the center tap.
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@ogiwankenobi, wire mo lang muna sir ng ganito... use filter caps that you have but make sure to connect the junction of the two caps to the center tap of your trafo...
(http://sound.westhost.com/p3a-f2.gif)
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@ogiwankenobi, wire mo lang muna sir ng ganito... use filter caps that you have but make sure to connect the junction of the two caps to the center tap of your trafo...
(http://sound.westhost.com/p3a-f2.gif)
Did rewire based on your suggested schematic. Reading is +-56V. . . :-\
BTW, have tried this schematic on a 12-0-12v 3A before, ganun din behavior. . . :-\
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Did rewire based on your suggested schematic. Reading is +-56V. . . :-\
BTW, have tried this schematic on a 12-0-12v 3A before, ganun din behavior. . . :-\
Naku baka ang kinukuha mo sir is the "ends" of the split supply. With the negative (black) prong of your AMM connected to the GND (junction of your cap filter) and the positive (red) prong of your AMM connected to the positive leg of the positive filter cap you should only get around 24Vdc (AMM must be in DC).
Make sure you connect the "0" (center tap) of your tranny to the junction of your filter cap or else magiging voltage doubler yan like sir marckrenz said.
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Naku baka ang kinukuha mo sir is the "ends" of the split supply. With the negative (black) prong of your AMM connected to the GND (junction of your cap filter) and the positive (red) prong of your AMM connected to the positive leg of the positive filter cap you should only get around 24Vdc (AMM must be in DC).
Make sure you connect the "0" (center tap) of your tranny to the junction of your filter cap or else magiging voltage doubler yan like sir marckrenz said.
Ground to positive po is +56V, ground to negative is -56v din, positive to negative 112v. Haaay ang gulo. Btw, i've tried center and 17v to bridge, dun lumabas yung 56v from positive to negative. Di ko lang alam kung san ako magga-ground. sa Junction ng caps? Lapit na ako mapundi! grrrrr!!!
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Ground to positive po is +56V, ground to negative is -56v din, positive to negative 112v. Haaay ang gulo. Btw, i've tried center and 17v to bridge, dun lumabas yung 56v from positive to negative. Di ko lang alam kung san ako magga-ground. sa Junction ng caps? Lapit na ako mapundi! grrrrr!!!
Uy sobra ang taas, di naman naka 110 yun primary ano po? ;D
Yun GROUND must be the junction of the two filter caps, this is also connected to the center tap of the tranny.
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obi,
pahinga ka muna ng 2 days, tapos saka mo balikan...... ;D
kailagan fresh ang mind mo.... ;D
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check mo kung may voltage between the junction of the caps & the transformer CT
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check mo kung may voltage between the junction of the caps & the transformer CT
Sir wala pong voltage pero may connection naman.
@Sir Jojo: Sir chineck ko po connection sa primary, 0-220. Di po ba pag sa 110 ko kinabit magdo doble ang voltage? o current?
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Sir wala pong voltage pero may connection naman.
@Sir Jojo: Sir chineck ko po connection sa primary, 0-220. Di po ba pag sa 110 ko kinabit magdo doble ang voltage? o current?
da best yata suggestion ni sir tony!
obi,
pahinga ka muna ng 2 days, tapos saka mo balikan...... ;D
kailagan fresh ang mind mo.... ;D
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Hehehe!!! Sige, will take his advice. . . or find another tranny to test kung ganun pa din ang behavior.
BTW, tried 4 discreet diodes for a bridge kaso ganun pa din. :-\
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Hehehe!!! Sige, will take his advice. . . or find another tranny to test kung ganun pa din ang behavior.
BTW, tried 4 discreet diodes for a bridge kaso ganun pa din. :-\
mayroon lang talaga mali eh, pambihira naman mga diodes yan hehehe... kung 17Vac x 2 ang secondary, dapat +/-24Vdc (48Vdc peak to peak) lang siya after rectification and filtering.
tama si Tony, baka kasi it's so obvious na kaya hindi mo makita, better take some rest. pero kung ako yan di ko titigilan yan, nanggigigil na ako diyan sa power supply mo sir. ;D
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Been following this Power Supply problem.... Nakakagigil nga yang psu na yan. :) :) :)
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@ogiwankenobi, wire mo lang muna sir ng ganito... use filter caps that you have but make sure to connect the junction of the two caps to the center tap of your trafo...
(http://sound.westhost.com/p3a-f2.gif)
Sir JojoD pasensya na po, medyo na po talaga ako. Above schematic is for dual supply, tapos eto po para sa voltage doubler:
http://en.wikipedia.org/wiki/File:Full-wave_voltage_doubler.svg
Di po ba walang pinagkaiba? o yung caps nya is non-polar? ???
Muka ngang nagiging voltage doubler yung circuit. If so, what circuit is for a full bridge dual supply? anggulooooooo!!!
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@ogiwankenobi, wire mo lang muna sir ng ganito... use filter caps that you have but make sure to connect the junction of the two caps to the center tap of your trafo...
(http://sound.westhost.com/p3a-f2.gif)
Sir JojoD pasensya na po, medyo naguguluhan na po talaga ako. Above schematic is for dual supply, tapos eto po para sa voltage doubler:
http://en.wikipedia.org/wiki/File:Full-wave_voltage_doubler.svg
Di po ba walang pinagkaiba? o yung caps nya is non-polar? ???
Muka ngang nagiging voltage doubler yung circuit. If so, what circuit is for a full bridge dual supply? anggulooooooo!!!
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master jojo if i may...
magkaiba yan.
sa voltage doubler, transformer CT is connected to capacitor junction. period. no connection to circuit ground.
sa dual supply, transformer CT is connected to capacitor junction AND to circuit ground. hence you have to ensure there is continuity sa center tap, cap junction AND circuit ground.
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ayun sapul na sapul na ni mark...
sabi ko kasi sayo ogiwankenobi, i-wire mo yun power supply, tapos take readings, then take pics.
for clarity's sake, lagyan natin ng pangalan...
1. V+ = Positive potential with respect to GROUND and should be around +24VDC with a transformer secondary of 17-0-17 AC.
2. GROUND = junction of your filter cap, also connected to trany center tap and circuit ground.
3. V- = Negative potential with respect to GROUND and should be around -24VDC with a transformer secondary of 17-0-17 AC.
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Eheheheh!!! So kulang pala kahapon ng circuit ground kaya nagbo-voltage doubling.Ayus!!! Sige, try ko ulit.
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Voltage readings when CT-Cap junction-Circuit ground was reconnected together with the +- rails: +-46V!!!! ???
Question: When you guys say ground, does it necessarily mean that I "Earth" the Center tap?
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make sure all GROUND points in the circuit are connected to the cap junction which should then be connected to the trans CT.
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make sure all GROUND points in the circuit are connected to the cap junction which should then be connected to the trans CT.
Sir pinagsama ko po lahat, bale common ground yung anim na GC then connected to 1 black wire going to the cap junction.
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Voltage readings when CT-Cap junction-Circuit ground was reconnected together with the +- rails: +-46V!!!! ???
Question: When you guys say ground, does it necessarily mean that I "Earth" the Center tap?
Ok yan, ngayon kunan mo ng pic yun circuit mo sir para makita namin.
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Ok yan, ngayon kunan mo ng pic yun circuit mo sir para makita namin.
Eto po pics:
(http://img688.imageshack.us/img688/9871/date004.th.jpg) (http://img688.imageshack.us/i/date004.jpg/)
Trafo na point-to-point ;D
(http://img686.imageshack.us/img686/2841/date003.th.jpg) (http://img686.imageshack.us/i/date003.jpg/)
RCA Inputs from my old VCD player Note: 1 ground lead going to perfboard.
(http://img28.imageshack.us/img28/4827/date002.th.jpg) (http://img28.imageshack.us/i/date002.jpg/)
White, red, and green pairs as output leads (right side w/ green caps is IGC, left side is NIGC)
(http://img189.imageshack.us/img189/6325/date001.th.jpg) (http://img189.imageshack.us/i/date001.jpg/)
(http://img41.imageshack.us/img41/8166/date000.th.jpg) (http://img41.imageshack.us/i/date000.jpg/)
Underside. Black and white wires as grounding starred sa power ground. Yellow as Negative Rail, Red as Positive Rail.
(http://img19.imageshack.us/img19/4347/date005b.th.jpg) (http://img19.imageshack.us/i/date005b.jpg/)
Another View. . .
Linis nyan dati, dinagdagan ko lang ng mga black grounding wires and red and yellow power wires to clearly emphasize power distributions.
BTW, couldn't find 1uf np and .22uf polar so I paralleled 2x.47uf electrolytics to get 1uf and series'd (+ to +) another pair for the .22uf np.
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Sumakit mata ko ah... ;D
From the 1st pic looks ok naman yun bridge mo, hindi ko lang makita yun polarity ng caps. Naka wire na ba yan psu mo? Sana psu muna concentrate natin para masolve yun readings mo. Tsaka na natin pagsunugan ng kilay yun layout ng amp. :D
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Sumakit mata ko ah... ;D
From the 1st pic looks ok naman yun bridge mo, hindi ko lang makita yun polarity ng caps. Naka wire na ba yan psu mo? Sana psu muna concentrate natin para masolve yun readings mo. Tsaka na natin pagsunugan ng kilay yun layout ng amp. :D
Sir positive side po ng bridge to positive side ng 2200uf na cap, then negative side ng bridge to negative side ng another cap. junctioned po yung dalawang cap to which the CT and the circuit was connected. . .
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Sir positive side po ng bridge to positive side ng 2200uf na cap, then negative side ng bridge to negative side ng another cap. junctioned po yung dalawang cap to which the CT and the circuit was connected. . .
Tama naman sir, basically dapat wala ka problem sa psu setup mo... try mo kaya ibang multimeter pag measure?
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Tama naman sir, basically dapat wala ka problem sa psu setup mo... try mo kaya ibang multimeter pag measure?
Oo nga po e, but assuming tama yung PSU, tumutunog naman, kaso may hum and grabe pa din ang heat buildup, maski walang load, to tha point na 1 chip went up in flames. Saw it with my very own eyes.
I'm considering splitting the center tap para maging dual secondary
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Oo nga po e, but assuming tama yung PSU, tumutunog naman, kaso may hum and grabe pa din ang heat buildup, maski walang load, to tha point na 1 chip went up in flames. Saw it with my very own eyes.
I'm considering splitting the center tap para maging dual secondary
Yun hum and heat is a sign that something is wrong, sana wag mo muna kabit sa amp until you solve the psu problem first. Isa-isa lang sir, mauubos lahat yan chip mo hehehe...
Splitting the center tap solves nothing, hanapin po muna kung bakit ganun naman kataas ang DC voltage mo...
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disconnect mo muna lahat ng psu parts then resolder properly. baka may cold solder dyan. and you might as well heed sir jojo's advice, don't connect the amps until the psu problem is solved.
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done with the assembly using point to point method ;D
also added 2 more 10,000 uf/ 50v for a total of 4 filtering caps.
So far so good, no hum issues whatsoever, heatsink temp also varies based on vol settings ;D
modifications na lang sa back panel for rca, binding posts, etc....
Question po ulit:
Based on ns schematics meron blocking cap connected between sa 680ohms at sa ground, yung sakin di ko nilagyan, may effect ba ito?
thanks! :)
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disconnect mo muna lahat ng psu parts then resolder properly. baka may cold solder dyan. and you might as well heed sir jojo's advice, don't connect the amps until the psu problem is solved.
Tried continuity tests using AMM, OK naman po lahat, grounding and power leads. Di po ba pag di nakakabit yung Ground-centertap sa circuit e mag bo-voltage doubling yung PSU? Di kaya sira yung filter caps?
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sa totoo lang, kahit isang side pa lang ng 17-0-17 volt trafo mo ang nakakabit, dapat kuha na yung +/- 24 volts....
so ang payo ko, kalasin mo lahat yan, testingin mo isa, isa...then set aside mo...ngayong week-end, manood ka ng sine ng marelax ang mind mo...
saka mo na lang balikan ulit... ;D ganyan ang gawa ko pag me problema....pahinga muna ng isa o dalwang araw... ;D
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Based on ns schematics meron blocking cap connected between sa 680ohms at sa ground, yung sakin di ko nilagyan, may effect ba ito?
ingatan mo lang na hindi mapasukan ng dc yung input mo, pag nangyari yon, sunog ang speaker mo....
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ingatan mo lang na hindi mapasukan ng dc yung input mo, pag nangyari yon, sunog ang speaker mo....
thanks sir tony, lagyan ko na lang ng caps...better safe than sorry 8)
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sa totoo lang, kahit isang side pa lang ng 17-0-17 volt trafo mo ang nakakabit, dapat kuha na yung +/- 24 volts....
so ang payo ko, kalasin mo lahat yan, testingin mo isa, isa...then set aside mo...ngayong week-end, manood ka ng sine ng marelax ang mind mo...
saka mo na lang balikan ulit... ;D ganyan ang gawa ko pag me problema....pahinga muna ng isa o dalwang araw... ;D
Bought a Bnew DMM this afternoon. Readings were +-27V. . . . So it was a faulty MM after all. . . .
Will try to revise my 6channel (2 IGC and 4 NIGC) to straight IGCs based on the "GainClown" schematic. Hopefully matapos ko this evening. . . .
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you can try to replace the batteries on your old dmm and see if the readings are as they should be....
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sa totoo lang, kahit isang side pa lang ng 17-0-17 volt trafo mo ang nakakabit, dapat kuha na yung +/- 24 volts....
so ang payo ko, kalasin mo lahat yan, testingin mo isa, isa...then set aside mo...ngayong week-end, manood ka ng sine ng marelax ang mind mo...
saka mo na lang balikan ulit... ;D ganyan ang gawa ko pag me problema....pahinga muna ng isa o dalwang araw... ;D
sama tayo pag nanood ng sine para marelax naman...
Bought a Bnew DMM this afternoon. Readings were +-27V. . . . So it was a faulty MM after all. . . .
Will try to revise my 6channel (2 IGC and 4 NIGC) to straight IGCs based on the "GainClown" schematic. Hopefully matapos ko this evening. . . .
buset na AMM mo ser pinasakit ulo mo ah... ;D ;D ;D
done with the assembly using point to point method ;D
also added 2 more 10,000 uf/ 50v for a total of 4 filtering caps.
So far so good, no hum issues whatsoever, heatsink temp also varies based on vol settings ;D
modifications na lang sa back panel for rca, binding posts, etc....
Question po ulit:
Based on ns schematics meron blocking cap connected between sa 680ohms at sa ground, yung sakin di ko nilagyan, may effect ba ito?
thanks! :)
That cap prevents DC build up at the input of the opamp because of the thing you see on datasheets called "input offset current".
Hoping this may not end up being a subjective vs objectivist topic, you can actually get away with it if you keep your impedances low, for example, look at the schematic that obiwankenobi posted, that would work but it uses ridiculously high impedance ratios.
Hth
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Hoping this may not end up being a subjective vs objectivist topic, you can actually get away with it if you keep your impedances low, for example, look at the schematic that obiwankenobi posted, that would work but it uses ridiculously high impedance ratios.
I don't see that it can..... ;D
if you have an input capacitor, you can get away with it, but speaker safety is imho a prime concern....
you don't want your P150 peso chip ruining your P3000peso speakers, do you? ;D ;D ;D
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I don't see that it can..... ;D
if you have an input capacitor, you can get away with it, but speaker safety is imho a prime concern....
you don't want your P150 peso chip ruining your P3000peso speakers, do you? ;D ;D ;D
I'm sure you know that some would think otherwise... ;D
Yes the input cap prevents any DC from the source from going through and be amplifier 20 times... ;D But I believe blackmoly was referring to the other cap in series with a resistor on the other input pin of the chip. ;D
Aha, a ruined speaker is always a bad day. ;D ;D ;D
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But I believe blackmoly was referring to the other cap in series with a resistor on the other input pin of the chip.
yes......that is why i warned about having dc at the input.... ;D
that cap was placed there for exactly that reason.... ;D
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yes......that is why i warned about having dc at the input.... ;D
that cap was placed there for exactly that reason.... ;D
or a more lucrative approach... active DC Servo... ;D ;D ;D
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thanks sir Tony/ sir Jojod
yan pala ang purpose ng coupling caps na nilalagay sa input ng mga amplifier ckt...di lang pala audio signal kayang i-amplify pati dc or noise pwede rin :o
walang available na 22uf nonpolar dito sa local elex shop sa amin, will scout sa may guadalupe area then pag wala diretcho na sa raon 8)
btw here's the schematic na ginamit ko:
(http://i192.photobucket.com/albums/z21/blackmoly_photos/LM3875-Gainclone-Chip-Amp-Schematic.png)
at eto yung sinasabi kong dc blocking cap
(http://i192.photobucket.com/albums/z21/blackmoly_photos/01144901.jpg)
as of now nabuo ko na yung amp and chassis with all the wirings and modifications....pics to follow ;D
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walang available na 22uf nonpolar
you can use 2 x 47ufd caps wired back to back in series to form a non polar 22uf cap....
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you can use 2 x 47ufd caps wired back to back in series to form a non polar 22uf cap....
Ooops! teka. . . . Non-polar? ba't 'tong sa schematic ko electrolytic?
http://schematics.circuitdiagram.net/viewer.php?id=bwy1259118639a.JPG
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Ooops! teka. . . . Non-polar? ba't 'tong sa schematic ko electrolytic?
http://schematics.circuitdiagram.net/viewer.php?id=bwy1259118639a.JPG
you can get away with it because there is no net dc build-up in that cap...but since an ac wave which is developed at the output has both positive and negative peak swings, then your cap is seing these voltages...and neither ac voltages are developed accross those caps...
so that is the justification for using bipolar caps in there.....
did you follow me? ;D
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just as jojo commented, you can play around with feedback resistor values, as it stands your gain is about 11, you can increase or decrease that gain by changing value's of R5 and R4, lowering the value of R4 increases the gain, while lowering the value of R5 decreases the gain, and vice versa..
value of C3 determines the lower corner frequency, decreasing its value increases the corner frequency, while increasing the value decreases the corner frequency.
you can not increase the value of C3 as high as you want, because doing so affects the speed of your amp during overloads...your amp recovers slower...
I would replace C1 with a film type instead of that electrolytic.....i am allergic to elctros in the coupling cap positions...
so you see, there are lots of tweaks that you can do once you get your amp going.... ;D
OMG, this thread i started in Jul 24, 2003 at 05:41 PM is still alive.... ;D ;D ;D
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so you see, there are lots of tweaks that you can do once you get your amp going.... ;D
OMG, this thread i started in Jul 24, 2003 at 05:41 PM is still alive.... ;D ;D ;D
Very true, do it right first before venturing on to other possible alterations...
Time flies fast... ;D ;D ;D
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OMG, this thread i started in Jul 24, 2003 at 05:41 PM is still alive.... ;D ;D ;D
ang tagal na pala sir tony, too bad lately ko lang nakita yung thread... ;D
Very true, do it right first before venturing on to other possible alterations...
Time flies fast... ;D ;D ;D
x2! kaya pala when i asked sir tony about doon sa snubberized psu he answered build it first then when everything is working then have it snubberized then see if you like it... :)
on topic here's my semi finished lm3875:
sorry for the crappy pics
replaced the plastic handle with 4 allen screws with nut, drill holes for the toggle switch, indicator
and vol control (for now di ko muna kinabit vol control)
(http://i192.photobucket.com/albums/z21/blackmoly_photos/Pic4143-1.jpg)
almost done with backpanel modifications, installed iec socket, binding posts, input rca's...
by default meron na pre drilled holes yung likod na hindi match sa preffered placement ko :(
(http://i192.photobucket.com/albums/z21/blackmoly_photos/Pic4145-1.jpg)
will also replace all outside screws with allen screws para uniform...
next time na lang yung internals, need pa ng cable management ;D ;D
thanks :)
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great job sir blackmoly, congrats sir! 8)
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allen screws para uniform...
it is nice to cultivate an attitude of "attention to details"......you will move on to more cunning and daring projects.... ;D
speaking of screws, have you been to Arranque in avenida? they have all sorts of screws there, stainless are best for casings, torx screws are also nice.... ;D
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speaking of screws, have you been to Arranque in avenida? they have all sorts of screws there, stainless are best for casings, torx screws are also nice.... ;D
Screw Kingdom, Screw King, Screw Queen, Screw Warehouse, Screw Master, Screw Haven... and of course, To Suy Screw and Hardware.
Arranque, your one stop shop for all your screwing needs. ;)
(Parang hindi yata tama yun choice of words ko hehehe... ;D ;D ;D)
@blackmoly, while your shopping for screws, may I suggest you try Ambos Mundos' Pork Asado along Florentino Torres... ;) ;) ;)
@Tony, an outlet of To Suy (the one along Tomas Mapua) carries original Greenlee hole punches in different sizes, just in case you're in the lookout for one.
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on topic here's my semi finished lm3875:
sorry for the crappy pics
(http://i192.photobucket.com/albums/z21/blackmoly_photos/Pic4143-1.jpg)
(http://i192.photobucket.com/albums/z21/blackmoly_photos/Pic4145-1.jpg)
@Sir JojoD
Ala bang Screw Yu GMA? ;D
Uy! BabyG Clone!!!! Heheheh!!! Kidding lang. . .
Ganda Sir blackmoly.
Kainggit naman kayo, Lapit nyo sa Raon. Daming available components, even casings. Dito sa Mindanao I'll have to do with an old VCD player and travel 37kms to another town just to look for chips and a friggin .22nf non polars. Swertehan pa kung may stock o wala.
On to my project:
1. 6channel reduced to 3channel surround power amp. Plan for future bi-amped surrounds postponed. For now.
2. Changed PSU from 17-0-17 6A to 12-0-12 3A to lessen heat.
3. Played the whole day with no hums nor heating. Played various genre e.g. Metallica, Dream Theater, Michael Buble, Peter White, The science of getting Rich by Wallace D. Wattles ;D
Things to be done:
1. Finish Amp casing
2. Incorporate a CP-charger-powered lightspeed attenuator for the 3 channels (1LED to 3 LDRs, pede ba yun? Para walang channel balance issues?)
3. Change the 6 spring/clip spkr terminals to 3 pairs fancy binding post.
Will post pics later this afternoon. Biking muna 'ko para ma-relax as per sir Tony's suggestion. ;D
Timeline: Tuesday next week.
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Screw Kingdom, Screw King, Screw Queen, Screw Warehouse, Screw Master, Screw Haven... and of course, To Suy Screw and Hardware.
Arranque, your one stop shop for all your screwing needs. ;)
(Parang hindi yata tama yun choice of words ko hehehe... ;D ;D ;D)
@blackmoly, while your shopping for screws, may I suggest you try Ambos Mundos' Pork Asado along Florentino Torres... ;) ;) ;)
@Tony, an outlet of To Suy (the one along Tomas Mapua) carries original Greenlee hole punches in different sizes, just in case you're in the lookout for one.
jojo, thanks for the heads up, i still have those punches from the 70's.....will look into those green lee's... ;D
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great job sir blackmoly, congrats sir! 8)
thanks sir jojo ;D
thanks nga pala sa pagsagot sa inquiry ko SA Pm :)
it is nice to cultivate an attitude of "attention to details"......you will move on to more cunning and daring projects.... ;D
speaking of screws, have you been to Arranque in avenida? they have all sorts of screws there, stainless are best for casings, torx screws are also nice.... ;D
thanks sir tony ;D
hopefully i can do more projects this summer since walang pasok sa school :)
need pa ng practice for that "cunning and daring" projects :o
@ sir tony/ sir jojo
as for my screws i got them for free ;D ;D ;D
w0w thanks for the info with regards to nuts and screwing needs ;D
ang alam ko lang is yung to suy sa may recto but hindi pa ako nakakapasok.
Ganda Sir blackmoly.
Kainggit naman kayo, Lapit nyo sa Raon. Daming available components, even casings. Dito sa Mindanao I'll have to do with an old VCD player and travel 37kms to another town just to look for chips and a friggin .22nf non polars. Swertehan pa kung may stock o wala.
On to my project:
1. 6channel reduced to 3channel surround power amp. Plan for future bi-amped surrounds postponed. For now.
2. Changed PSU from 17-0-17 6A to 12-0-12 3A to lessen heat.
3. Played the whole day with no hums nor heating. Played various genre e.g. Metallica, Dream Theater, Michael Buble, Peter White, The science of getting Rich by Wallace D. Wattles ;D
Things to be done:
1. Finish Amp casing
2. Incorporate a CP-charger-powered lightspeed attenuator for the 3 channels (1LED to 3 LDRs, pede ba yun? Para walang channel balance issues?)
3. Change the 6 spring/clip spkr terminals to 3 pairs fancy binding post.
Will post pics later this afternoon. Biking muna 'ko para ma-relax as per sir Tony's suggestion. ;D
Timeline: Tuesday next week.
na experience ko rin yan sa province namin (bacolod) bro, i have to travel a long distance din to buy parts for our school project dati, that's why when i arrived in manila, raon agad gusto ko puntahan ;D
very promising project bro 8)
abangan namin yan ;D ;D
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Update:
i've installed a 22 uf/ 100v nonpolar electrolytic caps, one thing na na notice ko is how the temp was dramatically reduced, the amp now runs cooler at moderate to loud levels ;D
here are some pictures 8) again
dc blocking caps not shown
(http://i192.photobucket.com/albums/z21/blackmoly_photos/Pic4153.jpg)
it's my first time to use a point to point method, medyo tricky pala talaga. i decided to cut unused pins para mas madali....
backpanel w/ unused pre drilled holes :P
(http://i192.photobucket.com/albums/z21/blackmoly_photos/Pic4169.jpg)
with sir anthony's diy speakers, my diy speaker wires and diy ic diy lahat ;D
(http://i192.photobucket.com/albums/z21/blackmoly_photos/Pic4178.jpg)
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@Sir JojoD
Ala bang Screw Yu GMA? ;D
Sa bandang Mendiola sir meron yan... ;D ;D ;D
jojo, thanks for the heads up, i still have those punches from the 70's.....will look into those green lee's... ;D
good for you, those tools command a hefty price tag nowadays... :o
thanks sir jojo ;D
thanks nga pala sa pagsagot sa inquiry ko SA Pm :)
welcome sir :)
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Update:
i've installed a 22 uf/ 100v nonpolar electrolytic caps, one thing na na notice ko is how the temp was dramatically reduced, the amp now runs cooler at moderate to loud levels ;D
that's because your chip is sinking/sourcing current at the output even at idle, if you examine the AC characteristics of your amp, you'll notice that this cap is in fact installed in the feedback loop (i'm talking of the cap in series with the resistor going to ground), hence, even a small amount of DC input offset current present at the input would yield a higher source/sink voltage at the output because it is multiplied depending on your voltage gain.
for National chips, voltage gain for a non-inverting amp is computed G=1+(R2/R1). in most circuits, gain is about 20, and if you have a 0.005V of DC input offset, that would be multiplied 20 times! you'll end up with a stable 0.1V DC output offset that your amp would (depending on it's polarity) sink/source to the load at all times. this is bad, and not very healthy for your tweeters.
pay particular attention to the data sheet and white papers, study them. most things in there are not even taught in engineering and technical courses. ;) you learn them in real life. ;D
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that's because your chip is sinking/sourcing current at the output even at idle, if you examine the AC characteristics of your amp, you'll notice that this cap is in fact installed in the feedback loop (i'm talking of the cap in series with the resistor going to ground), hence, even a small amount of DC input offset current present at the input would yield a higher source/sink voltage at the output because it is multiplied depending on your voltage gain.
for National chips, voltage gain for a non-inverting amp is computed G=1+(R2/R1). in most circuits, gain is about 20, and if you have a 0.005V of DC input offset, that would be multiplied 20 times! you'll end up with a stable 0.1V DC output offset that your amp would (depending on it's polarity) sink/source to the load at all times. this is bad, and not very healthy for your tweeters.
pay particular attention to the data sheet and white papers, study them. most things in there are not even taught in engineering and technical courses. ;) you learn them in real life. ;D
thanks sir jojo :)
4x kong binasa paulit ulit bago ko na digest ;D
Tips noted ;D
Ang tinitingnan ko lang sa datasheet is schematic, pin config and parts list. But I do print the whole datasheet pero I'm too lazy na basahin lahat...tsk!
hunt mode ako for my next proj 8)
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thanks sir jojo :)
4x kong binasa paulit ulit bago ko na digest ;D
Tips noted ;D
Ang tinitingnan ko lang sa datasheet is schematic, pin config and parts list. But I do print the whole datasheet pero I'm too lazy na basahin lahat...tsk!
Ok lang yun sir, theory without practice is nil, while practice without theory is rather dangerous. Basta may fire extinguisher ka lang palagi sa tabi mo. ;D
Ang Datasheet parang Playboy mag po yan, don't just look at the pics and the centerfold... you must also read the articles! ;D ;D ;D
hunt mode ako for my next proj 8)
Tubo na po yan sir. :o 8)
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I can't help but notice that there's been a surge of DIYers who want to build gainclones for their HT and Audio systems. The basic gainclone is simple and easy to build so it's the perfect project for the beginner with mods and tricks as your skill progresses.
A few years ago, National published a white paper showing how to scale up their chips for more power handling, and so the birth of the gc bridge, gc paralleled, and gc bridged-paralleled. These configurations have paved the way for gainclones to power sub woofer systems. Some problems like current sinking/sourcing have been easily solved by active DC servo but this complicates everything and scares the heck out of a builder. ;D But a single chip is not just enough to power a sub, and more often it goes into protection (sPiKe for National chips) if not completely destroying the chip.
Not too long ago, Circlotron of diyAudio posted a gainclone "afterburner", more technically known as a current dumping circuit. With these modifications, all you need is a single chip and a couple of power transistors to build a sub amp.
I have studied and worked around with it many times (whenever I have the time) and so in the spirit of sharing, I drew this schematic for those who may want to try it out.
(http://img.photobucket.com/albums/v70/jojod818/JD%20Labs/gcx.jpg)
Notes:
1. Tons of choices for the power transistors are available, just pay attention to it's collector current and collector-emitter voltage.
2. Traditional power supply decoupling still applies (not shown in the schematic).
3. Output power transistors operates in Class B so suitable applications would be for powering a sub.
Disclaimer:
1. I would not be responsible for any damages you or your gears may incur. So safety first!
2. I just want to share ideas, so please don't don't blame me if it doesn't work.
PS:
Mine has been working for years now, powering a 12 inch sub. :P
(http://img.photobucket.com/albums/v70/jojod818/JD%20Labs/gcxactual.jpg)
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Ok lang yun sir, theory without practice is nil, while practice without theory is rather dangerous. Basta may fire extinguisher ka lang palagi sa tabi mo. ;D
Ang Datasheet parang Playboy mag po yan, don't just look at the pics and the centerfold... you must also read the articles! ;D ;D ;D
Tubo na po yan sir. :o 8)
lol! ;D ;D ;D
hopefully sana matuto rin ako sa tubo sir jojo, pero sa ngayon zero talaga ako :(
Update ko lang din final touches sa proj:
as i mount the top cover i noticed that it hits my traffo which is about 3-4mm higher than my case :(
so i decided to use plastic spacers as a remedy and for added ventilation as well ;D
used 9 allen screws on top.
(http://i192.photobucket.com/albums/z21/blackmoly_photos/Pic4200.jpg)
(http://i192.photobucket.com/albums/z21/blackmoly_photos/Pic4198.jpg)
100% complete (minus the vol. control) ;D
(http://i192.photobucket.com/albums/z21/blackmoly_photos/Pic4194.jpg)
gainclone scandal ;D
http://www.4shared.com/video/XehekANE/gainclone_lm3875.html?
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lol! ;D ;D ;D
hopefully sana matuto rin ako sa tubo sir jojo, pero sa ngayon zero talaga ako :(
Update ko lang din final touches sa proj:
as i mount the top cover i noticed that it hits my traffo which is about 3-4mm higher than my case :(
so i decided to use plastic spacers as a remedy and for added ventilation as well ;D
used 9 allen screws on top.
(http://i192.photobucket.com/albums/z21/blackmoly_photos/Pic4200.jpg)
(http://i192.photobucket.com/albums/z21/blackmoly_photos/Pic4198.jpg)
100% complete (minus the vol. control) ;D
(http://i192.photobucket.com/albums/z21/blackmoly_photos/Pic4194.jpg)
gainclone scandal ;D
http://www.4shared.com/video/XehekANE/gainclone_lm3875.html?
search mo sir sa net meron downloadable rca receiving tube manual, very good reading material. ;) parang transistor lang yan sir kaso baligtad nga lang. yun transistor pag uminit nasisira, yun tubo pag malamig hindi tumutunog. ;D ;D ;D
contact mo sir si edrel sison pagawa ka ng tranny with multi-tap high voltage secondaries, very useful sa tube experiments po yan. ;)
ayus yun scandal, kala ko naman kung ano na. ;D ;D ;D
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I can't help but notice that there's been a surge of DIYers who want to build gainclones for their HT and Audio systems. The basic gainclone is simple and easy to build so it's the perfect project for the beginner with mods and tricks as your skill progresses.
A few years ago, National published a white paper showing how to scale up their chips for more power handling, and so the birth of the gc bridge, gc paralleled, and gc bridged-paralleled. These configurations have paved the way for gainclones to power sub woofer systems. Some problems like current sinking/sourcing have been easily solved by active DC servo but this complicates everything and scares the heck out of a builder. ;D But a single chip is not just enough to power a sub, and more often it goes into protection (sPiKe for National chips) if not completely destroying the chip.
Not too long ago, Circlotron of diyAudio posted a gainclone "afterburner", more technically known as a current dumping circuit. With these modifications, all you need is a single chip and a couple of power transistors to build a sub amp.
I have studied and worked around with it many times (whenever I have the time) and so in the spirit of sharing, I drew this schematic for those who may want to try it out.
(http://img.photobucket.com/albums/v70/jojod818/JD%20Labs/gcx.jpg)
Notes:
1. Tons of choices for the power transistors are available, just pay attention to it's collector current and collector-emitter voltage.
2. Traditional power supply decoupling still applies (not shown in the schematic).
3. Output power transistors operates in Class B so suitable applications would be for powering a sub.
Disclaimer:
1. I would not be responsible for any damages you or your gears may incur. So safety first!
2. I just want to share ideas, so please don't don't blame me if it doesn't work.
PS:
Mine has been working for years now, powering a 12 inch sub. :P
(http://img.photobucket.com/albums/v70/jojod818/JD%20Labs/gcxactual.jpg)
Ganun pala yun? Kala ko isang malakas na GC Chip lang with low pass filter e OK na. Thanks for sharing Sir Jojo. Sakto to sa nag-iisang LM3886 ko (Crispy na kasi yung kapares nya nung tinry ko p2p GC) :P.
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search mo sir sa net meron downloadable rca receiving tube manual, very good reading material. ;) parang transistor lang yan sir kaso baligtad nga lang. yun transistor pag uminit nasisira, yun tubo pag malamig hindi tumutunog. ;D ;D ;D
contact mo sir si edrel sison pagawa ka ng tranny with multi-tap high voltage secondaries, very useful sa tube experiments po yan. ;)
ayus yun scandal, kala ko naman kung ano na. ;D ;D ;D
noted sir jojo.. 8)
napagtripan ko lang kunan gamit ang cp ko ;D ;D ;D
I can't help but notice that there's been a surge of DIYers who want to build gainclones for their HT and Audio systems. The basic gainclone is simple and easy to build so it's the perfect project for the beginner with mods and tricks as your skill progresses.
A few years ago, National published a white paper showing how to scale up their chips for more power handling, and so the birth of the gc bridge, gc paralleled, and gc bridged-paralleled. These configurations have paved the way for gainclones to power sub woofer systems. Some problems like current sinking/sourcing have been easily solved by active DC servo but this complicates everything and scares the heck out of a builder. ;D But a single chip is not just enough to power a sub, and more often it goes into protection (sPiKe for National chips) if not completely destroying the chip.
Not too long ago, Circlotron of diyAudio posted a gainclone "afterburner", more technically known as a current dumping circuit. With these modifications, all you need is a single chip and a couple of power transistors to build a sub amp.
I have studied and worked around with it many times (whenever I have the time) and so in the spirit of sharing, I drew this schematic for those who may want to try it out.
(http://img.photobucket.com/albums/v70/jojod818/JD%20Labs/gcx.jpg)
Notes:
1. Tons of choices for the power transistors are available, just pay attention to it's collector current and collector-emitter voltage.
2. Traditional power supply decoupling still applies (not shown in the schematic).
3. Output power transistors operates in Class B so suitable applications would be for powering a sub.
Disclaimer:
1. I would not be responsible for any damages you or your gears may incur. So safety first!
2. I just want to share ideas, so please don't don't blame me if it doesn't work.
PS:
Mine has been working for years now, powering a 12 inch sub. :P
(http://img.photobucket.com/albums/v70/jojod818/JD%20Labs/gcxactual.jpg)
nice! thanks for sharing sir jo ;D
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Ganun pala yun? Kala ko isang malakas na GC Chip lang with low pass filter e OK na. Thanks for sharing Sir Jojo. Sakto to sa nag-iisang LM3886 ko (Crispy na kasi yung kapares nya nung tinry ko p2p GC) :P.
Pwede din sir ang isang chip pero pag nilakas mo mag protect yun or worse mag crispy din yan...
I once opened a Paradigm PS1000 and PDR 12 subs and to my surprise it uses that same topology ... ;)
(http://www.avtalk.co.uk/attachment.php?attachmentid=3270&d=0)
(http://www.audio-ideas.com/reviews/graphics/pdr-12.jpg)
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as far as I can remember one of the best chip produced for gainclone is AN214Q. Used by Pioneer "de relo" car stereos in the mid 70's and 80's, characterized by a clean audio and sounding more like a Solid state than a gainclone, flat freq response and somewhat "warmer". there are still available stocks but the price has skyrocketed more than 10 times, used to cost only 30 pesos but now ranges from 600-800/pc., the cost of a driver tube.
IMO, this can be a better alternative for those seeking that warm tubey sound, provided that this gainclone is driven by a tube pre-amp. Added bonus is that you can squeeze out 5Watts RMS per chip, more than enough to an average sized listening room.
Anyone out there who could provide links to schematic or application notes about this gainclone chip?
Any additonal comments are welcome, as I have plans of making a hybrid amp out of this gainclone.
Here are a few specs:
AN214Q
Manufacturer- Matshusita
Operating voltage- 12 to 13.8Vdc
Max. P.out- 5 Watts
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Masters, may mapagbibilan ba ng DIY na gainclone pero 5channel?. . .
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Masters, may mapagbibilan ba ng DIY na gainclone pero 5channel?. . .
Sir you can pm sir JojoD., he's the man when it comes to to your inquiry :)
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as far as I can remember one of the best chip produced for gainclone is AN214Q. Used by Pioneer "de relo" car stereos in the mid 70's and 80's, characterized by a clean audio and sounding more like a Solid state than a gainclone, flat freq response and somewhat "warmer". there are still available stocks but the price has skyrocketed more than 10 times, used to cost only 30 pesos but now ranges from 600-800/pc., the cost of a driver tube.
IMO, this can be a better alternative for those seeking that warm tubey sound, provided that this gainclone is driven by a tube pre-amp. Added bonus is that you can squeeze out 5Watts RMS per chip, more than enough to an average sized listening room.
Anyone out there who could provide links to schematic or application notes about this gainclone chip?
Any additonal comments are welcome, as I have plans of making a hybrid amp out of this gainclone.
Here are a few specs:
AN214Q
Manufacturer- Matshusita
Operating voltage- 12 to 13.8Vdc
Max. P.out- 5 Watts
i've built one but it's the 15-watt version of the an214 without the Q. It needs a regulated 12v psu. Naalala ko we used to pair it with our audio booster na may input/ output transformers with mj2955 power transistors during highschool ;D
grabe ang mahal na pala, dati 120 lang isa :o
post your impressions (and pics) sir pag nakagawa ka na :)
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updates:
PSU:
split the secondary center tap @ 24v each
added another block diode kbpc3508
changed psu caps from 10kuf/50v (x4 jackon) to 1kuf/50v (x4 Tk)
added 4.7uf/ 50v (x2 rubycon)
also done some modifications like:
fix transformer mounting, no more spacers on top ;D
replace indicator and knob.
much better in terms of sq from my previous set up as per my music preference :)
but i've noticed mas mabilis uminit yung traffo kaysa dati, maybe because nawala yung mga big caps so medyo squeezed out si traffo ;D ;D ;D
@ All
has anyone tried using opa627 as a preamp? more like carlos's buffered gainclone...tia!
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i've built one but it's the 15-watt version of the an214 without the Q. It needs a regulated 12v psu. Naalala ko we used to pair it with our audio booster na may input/ output transformers with mj2955 power transistors during highschool ;D
grabe ang mahal na pala, dati 120 lang isa :o
post your impressions (and pics) sir pag nakagawa ka na :)
maski naman noon bata pa ako (parang kelan lang naman yun sir ;D) mahal na talaga pag original na Matsucrapa yun AN214Q, pero pag replacement lang nasa P50.00 lang... ;D
updates:
@ All
has anyone tried using opa627 as a preamp? more like carlos's buffered gainclone...tia!
been there already sir blackmoly, even tried the OPA627 + BUF634T combo... my suggestion is you go tubes na agad. ;) pero siyempre if you want to experience it then go ahead, maganda din naman siya para sa akin...
hanap ka na kasi ng tubes sir para makapag practice ka na... tag-ulan na oh masarap mag tubo... :-*
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Magkano na ba price range ng LM3875?
saka may fake ba nito? worried kasi ako bumili sa raon baka sira ibigay sa akin
might as well suggest a good reliable source saan pwede bumili
BTW, sir blackmoly, ilang VA yung transformer nyo? at 6A current rating? 24 x 2 , 288VA?
Saka question bakit mas ok na binabaan nyo yung output caps ng PSU? i usually see amplifiers
with big caps sa PSU nila..or pangit yung jackson caps since generic lang sya..unlike rubycons
Thanks sa mag reply,,
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@ sir jojod
thanks sa info ;D
i'll pass na lang at derecho tubes na :)
mahal din kasi yang opa627 ;D
sa raon pa rin ba bilihan ng mga tubes? tia!
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Magkano na ba price range ng LM3875?
saka may fake ba nito? worried kasi ako bumili sa raon baka sira ibigay sa akin
might as well suggest a good reliable source saan pwede bumili
BTW, sir blackmoly, ilang VA yung transformer nyo? at 6A current rating? 24 x 2 , 288VA?
Saka question bakit mas ok na binabaan nyo yung output caps ng PSU? i usually see amplifiers
with big caps sa PSU nila..or pangit yung jackson caps since generic lang sya..unlike rubycons
Thanks sa mag reply,,
around 250/pc (few months ago) sa alexan , nagtanong din ako sa newport kaso out of stock at that time :)
tingin ko wala namang sigurong fake....
yup 6A yung transformer ko with 50v secondary (2*24V)
pwede rin higher than 6A if you want para hindi bitin sa bass @ higher volumes ;D
sa caps naman ok naman ang jackon, better than generic china caps pero if budget permits or readily available then go for japan caps like nichicon, panasonic, elna etc.
ok naman yung 10kuf, tinest ko lang out of curiosity and also based sa mga nababasa ko if 1kuf yung gagamitin then i like the sq so stick ako sa 1kuf...depende pa rin sir sa preferrence mo :)
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@ sir jojod
thanks sa info ;D
i'll pass na lang at derecho tubes na :)
mahal din kasi yang opa627 ;D
sa raon pa rin ba bilihan ng mga tubes? tia!
no problem sir. :)
sa Raon sir ang alam ko meron tubes ay sa Deeco, Pacific Electronics, at yun Watson's sa may F. Torres. try niyo din sir si mang Gerry sa buy and sell baka meron pa siya spare tubes. happy hunting! :)
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Magkano na ba price range ng LM3875?
saka may fake ba nito? worried kasi ako bumili sa raon baka sira ibigay sa akin
might as well suggest a good reliable source saan pwede bumili
BTW, sir blackmoly, ilang VA yung transformer nyo? at 6A current rating? 24 x 2 , 288VA?
Saka question bakit mas ok na binabaan nyo yung output caps ng PSU? i usually see amplifiers
with big caps sa PSU nila..or pangit yung jackson caps since generic lang sya..unlike rubycons
Thanks sa mag reply,,
bale wala na po kasi kahit lakihan niyo ang value nun capacitor, kung babasahin niyo po yun datasheet makikita ninyo yun power supply ripple rejection ratio na published ng manufacturer. so kahit lakihan niyo po yun value ng caps masasayang lang dahil sa Law of Diminishing Returns.
yun Jackon na caps wala ako kaswerte-swerte diyan, yun mga 50V ratings nila 40V pa lang sumasabog na. based on my experience lang po.
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TDA1521 / 12AU7 Hybrid
an aquintance gave me a piece of TDA1521 gainclone, intrigued by the specs from Philips, gave me an idea of hyping it up more with a 12AU7 driver.
The result:
Strings & Percussion-smooth and detailed, I can't believe these minimalist gainclone can deliver an almost flawless performance.
Bass- Excellent control and tight, 15watts per channel can kick more than enough in an average size room.
Vocals- Slight edgy, but acceptable (I was expecting the vocals delivered by a pure tube amp, the fault was mine...)
Few technical specs.
1. PS for the gainclone is capacitance multiplier, hence hum is totally eliminated.
2. Single point grounding is strictly implemented
3.Signal carrying wires used were shielded & aircraft grade silver coated
Bypassng the tube driver, the amp sounded just like a common amp in its category, details and warmth were lost, vocals, mid and highs were highly artificial.
Overall a very nice alternative to a pure valve amp, especially practical when used daily on a long periods of listening.
Some few pics during construction and test running
(http://i646.photobucket.com/albums/uu184/efrennoble/tube%20projects/Image046-1.jpg)
(http://i646.photobucket.com/albums/uu184/efrennoble/tube%20projects/Image050-2.jpg)
(http://i646.photobucket.com/albums/uu184/efrennoble/tube%20projects/Image048.jpg)
the volume control not yet installed
(http://i646.photobucket.com/albums/uu184/efrennoble/tube%20projects/Image051.jpg)
the tube, Japanese made 12AU7, purchased at AMX/Kinetic at a reasonable price :)
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Sir Efren...meron ka na naman bagong project ha! Pa-audition pagtapos hehehe! Ako lang naman ang nag-iisang fan mo eh! :)
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Sir Efren...meron ka na naman bagong project ha! Pa-audition pagtapos hehehe! Ako lang naman ang nag-iisang fan mo eh! :)
mas madalas akong mag-"hibernate". Cge pasyal ka lang, tatlong bunrok lang naman ang pagitan ;D ;D ;D
Ride your kawasaki bka maisipan natin mag joyride along the siera madre, and "LET THE GOOD TIMES ROLL!"
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way to go efren! very nice project sir... 8)
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way to go efren! very nice project sir... 8)
Many thanks sir, kayo po ay isa sa mga convincing factors kaya ko nagawa yan! ;)
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Many thanks sir, kayo po ay isa sa mga convincing factors kaya ko nagawa yan! ;)
Let's keep the gainclones alive sir.... ;)
Try din natin in the future gumamit ng Sanyo (STK) thick film hybrid chips, medyo mahirap lang maghanap ng originals pero it's a worthwhile project imo. :)
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Pahabol sir JO!
CONGRATZ po sa new baby :D :D :D
sigurado magiging busy na kayo!
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Pahabol sir JO!
CONGRATZ po sa new baby :D :D :D
sigurado magiging busy na kayo!
Naku maraming salamat po sir Efren! Sana nga this weekend na at ako'y inip na din... ;D ;D ;D
Siguradong puyat session ito sir. ;D
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medyo nakakaintindi na sa amp building... going to try a p2p lm1875 first. would a pc psu heatsink be enough for one chip powered by a 16-0-16 transformer?
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medyo nakakaintindi na sa amp building... going to try a p2p lm1875 first. would a pc psu heatsink be enough for one chip powered by a 16-0-16 transformer?
pwede yan....
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mga sirs saan nakakabili locally ng branded na vol pot like alps? may static kasi yung vol pot ko (generic, big)...tia :)
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sa eleshop at watson's meron sir. pero bago mo sisihin yun pot check mo muna baka may input offset voltage ka sa input side ng gc mo. pag meron kahit alps pa yan magkakaroon din ng static.
HTH
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pwede yan....
thanks masterT
check mo muna baka may input offset voltage ka sa input side ng gc mo. pag meron kahit alps pa yan magkakaroon din ng static.
would it help if we put the volume control after the input cap? or is another dc blocking cap preferred?
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would it help if we put the volume control after the input cap?
the pot should be before any input cap...
or is another dc blocking cap preferred?
ideally, there shouldn't be any cap, but because of the offsets that run along the input pins and feedback resistor, one cap at the input should be fine because the preceding stage (source) should/would/must have no DC present with the signal.
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Thanks for this thread and the guidance of the masters I have built my very first amplifier. Malinis talaga ang LM1875 kahit nagkamali ako ng kinabit na resistor sa pin#2, 10k sa halip na 1k kaya sobrang baba ng gain (later computed to be 3.2, much less than the 10 recommended) pero wala naman oscillation, mahina lang talaga ang output. Nai-correct din naman at maayos tumunog, lalo na sigurado yung LM3886. Can't wait to build my next amp!
Medyo OT: I have just completed the National Semiconductor online seminar "Reducing System Cost with High Performance Audio Amplifiers" and I couldn't fail but notice this in the transcription of Slide 12:
For audio frequencies, the epic capacitor is very large. There is a trade-off between low frequency response, and system cost. From the equation, you can see that the output capacitor is universally proportional to the low cut-off frequency. So, for a typical head-phone load of 60 oms you wanted to couple in a 20 Hz audio signal - that would require an output capacitor of 500 micro-ferrets.
The only later that I realized the "epic" was the "output" capacitor. The last word really gave me a good laugh!
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Thanks for this thread and the guidance of the masters I have built my very first amplifier. Malinis talaga ang LM1875 kahit nagkamali ako ng kinabit na resistor sa pin#2, 10k sa halip na 1k kaya sobrang baba ng gain (later computed to be 3.2, much less than the 10 recommended) pero wala naman oscillation, mahina lang talaga ang output. Nai-correct din naman at maayos tumunog, lalo na sigurado yung LM3886. Can't wait to build my next amp!
Medyo OT: I have just completed the National Semiconductor online seminar "Reducing System Cost with High Performance Audio Amplifiers" and I couldn't fail but notice this in the transcription of Slide 12:
For audio frequencies, the epic capacitor is very large. There is a trade-off between low frequency response, and system cost. From the equation, you can see that the output capacitor is universally proportional to the low cut-off frequency. So, for a typical head-phone load of 60 oms you wanted to couple in a 20 Hz audio signal - that would require an output capacitor of 500 micro-ferrets.
The only later that I realized the "epic" was the "output" capacitor. The last word really gave me a good laugh!
congrats on your build......that 500uf capacitor can be dispensed with by using servos... ;D
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@Tony, for a decent gainclone, how much would one spend on "decent" parts, except the transformer.
I mean, panasonic caps or better, etc...
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@Tony, for a decent gainclone, how much would one spend on "decent" parts, except the transformer.
I mean, panasonic caps or better, etc...
the chips themselves are not that expensive, last time i checked, the LM3875 was around 300 pesos so the LM1875 should be way cheaper...
as for caps, DEECO sells nichicons and other good caps if you know how to look....
building gainclones should not be that costly....
(http://i20.photobucket.com/albums/b201/tecson/gaainclones/Cimg0326.jpg)
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sa eleshop at watson's meron sir. pero bago mo sisihin yun pot check mo muna baka may input offset voltage ka sa input side ng gc mo. pag meron kahit alps pa yan magkakaroon din ng static.
HTH
thanks sir jo, pag may static kasi pinapatay ko lang yung power ng amp then pinipihit ko yung vol back and forth then pag turn on ko nawawala na, 3 days a week ko lang kasi nagagamit around 4 hours max. Pero i'll study na rin about input offset voltage and do the necessary actions if ever meron. :)
Thanks for this thread and the guidance of the masters I have built my very first amplifier. Malinis talaga ang LM1875 kahit nagkamali ako ng kinabit na resistor sa pin#2, 10k sa halip na 1k kaya sobrang baba ng gain (later computed to be 3.2, much less than the 10 recommended) pero wala naman oscillation, mahina lang talaga ang output. Nai-correct din naman at maayos tumunog, lalo na sigurado yung LM3886. Can't wait to build my next amp!
Medyo OT: I have just completed the National Semiconductor online seminar "Reducing System Cost with High Performance Audio Amplifiers" and I couldn't fail but notice this in the transcription of Slide 12:
For audio frequencies, the epic capacitor is very large. There is a trade-off between low frequency response, and system cost. From the equation, you can see that the output capacitor is universally proportional to the low cut-off frequency. So, for a typical head-phone load of 60 oms you wanted to couple in a 20 Hz audio signal - that would require an output capacitor of 500 micro-ferrets.
The only later that I realized the "epic" was the "output" capacitor. The last word really gave me a good laugh!
congrats bro :)
the chips themselves are not that expensive, last time i checked, the LM3875 was around 300 pesos so the LM1875 should be way cheaper...
as for caps, DEECO sells nichicons and other good caps if you know how to look....
building gainclones should not be that costly....
(http://i20.photobucket.com/albums/b201/tecson/gaainclones/Cimg0326.jpg)
x2! although nagtanong ako sa salesperson sa 3rd level if they do have branded caps like panasonic or elna and sabi wala pero when i checked sa 2nd level meron elna, nichicon and TK ;D
check newport and alexan at raon for the lm3875 chip
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wala pero when i checked sa 2nd level meron elna, nichicon and TK
pansin ko nga, maraming magagandang caps sa DEECO ngayon.... ;D
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the chips themselves are not that expensive, last time i checked, the LM3875 was around 300 pesos so the LM1875 should be way cheaper...
as for caps, DEECO sells nichicons and other good caps if you know how to look....
building gainclones should not be that costly....
(http://i20.photobucket.com/albums/b201/tecson/gaainclones/Cimg0326.jpg)
Thanks Tony. I figure that building gainclones are not that expensive, though people are getting charged an arm and a leg! :o
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thanks sir jo, pag may static kasi pinapatay ko lang yung power ng amp then pinipihit ko yung vol back and forth then pag turn on ko nawawala na, 3 days a week ko lang kasi nagagamit around 4 hours max. Pero i'll study na rin about input offset voltage and do the necessary actions if ever meron. :)
congrats bro :)
x2! although nagtanong ako sa salesperson sa 3rd level if they do have branded caps like panasonic or elna and sabi wala pero when i checked sa 2nd level meron elna, nichicon and TK ;D
check newport and alexan at raon for the lm3875 chip
thanks bro!
yung sa kin walang kaingay-ingay, sinunod ko lang critical locations ng components, minimal wiring at syempre star grounding. or may advantage din ang p2p dahil i was able to mount the critical components as close to the chip as possible.
question ulit masters: may 12-0-12v 6a transformer ako, ang winding nya in pairs, 2 magkatabing magnet wires ang nakalabas kada tap. my theory is if i separate the two 0 volt taps, separate the two wires of one 12v tap and short the two wires of the other 12v tap, i would get a total of 48 volts doon sa 2 wires ng open 12v tap. then ang shorted 12v wires will be the zero-volt reference for a 24-0-24 secondary. tama ba ang theory ko and is it safe to do so?
balak ko sana gamitin for 3886 or 4780 amp para di na ko bibili ng transformer.
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may 12-0-12v 6a transformer ako, ang winding nya in pairs, 2 magkatabing magnet wires ang nakalabas kada tap. my theory is if i separate the two 0 volt taps, separate the two wires of one 12v tap and short the two wires of the other 12v tap, i would get a total of 48 volts doon sa 2 wires ng open 12v tap. then ang shorted 12v wires will be the zero-volt reference for a 24-0-24 secondary. tama ba ang theory ko and is it safe to do so?
i suppose if you get your phasing right, that will work, you do not even have to do it 24-0-24, you can just do it as 2 x 24 volts windings and do 2 x 35 volts dc full wave bridge instead..... ;D
you have another option though.....do a full wave voltage doubler instead, this way you do not have to tamper with your traffo.........
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Thanks Tony. I figure that building gainclones are not that expensive, though people are getting charged an arm and a leg! :o
that is why we post here.....people do not have to spend a fortune to get good sounds.... ;D
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i suppose if you get your phasing right, that will work, you do not even have to do it 24-0-24, you can just do it as 2 x 24 volts windings and do 2 x 35 volts dc full wave bridge instead..... ;D
you have another option though.....do a full wave voltage doubler instead, this way you do not have to tamper with your traffo.........
studied the phasing masterT, mali nga yung naisip ko. to maintain correct phasing dapat connect 1 12v wire to 1 12v wire at the opposite end, this will be the new 0v. tapos yung 2 open ends ng 12v ang magiging 48v. i'll just have to make sure there are no internal shorts on the parallel windings.
re: 2 x 35vdc. with this i can join 1 -35v and 1 +35v together to form a ground reference, so instead of 2 x 35vdc i'll have 1 +/-35. tama po ba?
preferrred ko pa rin makakuha ng dual supply kasi pag half-wave doubler half din utilization ng transformer. pag full wave doubler naman i'll have to settle for a single supply at tingin ko mas mahihirapan ako gawin yung amp.
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re: 2 x 35vdc. with this i can join 1 -35v and 1 +35v together to form a ground reference, so instead of 2 x 35vdc i'll have 1 +/-35. tama po ba?
that is correct....
preferrred ko pa rin makakuha ng dual supply kasi pag half-wave doubler half din utilization ng transformer. pag full wave doubler naman i'll have to settle for a single supply at tingin ko mas mahihirapan ako gawin yung amp.
kaya nga full wave voltage doubler, para full utilization ng transformer....downside is slightly poorer regulation, but if you are not doing full power sine wave testing i doubt you will notice the difference.... ;D
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that is correct....
kaya nga full wave voltage doubler, para full utilization ng transformer....downside is slightly poorer regulation, but if you are not doing full power sine wave testing i doubt you will notice the difference.... ;D
ok thanks! sa audio section naman. pwede kaya i-bridge 2 lm1875 without any capacitors? another theory is: since they will be a pair of inverted and non-inverted amps, any DC at the non-inverting half will be zeroed out by the inverting half. will this work out in reality? or are there other factors i overlooked? parang sobrang simple at maganda tingnan kung feedback/gain resistors lang sa audio section; sa power supply section na lang ang capacitors.
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pwede kaya i-bridge 2 lm1875 without any capacitors? another theory is: since they will be a pair of inverted and non-inverted amps, any DC at the non-inverting half will be zeroed out by the inverting half. will this work out in reality? or are there other factors i overlooked? parang sobrang simple at maganda tingnan kung feedback/gain resistors lang sa audio section; sa power supply section na lang ang capacitors.
i see no reason why it can not work...... ;D
choose devices that have identical input offset voltages to avoid further complications....
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ok thanks! sa audio section naman. pwede kaya i-bridge 2 lm1875 without any capacitors? another theory is: since they will be a pair of inverted and non-inverted amps, any DC at the non-inverting half will be zeroed out by the inverting half. will this work out in reality? or are there other factors i overlooked? parang sobrang simple at maganda tingnan kung feedback/gain resistors lang sa audio section; sa power supply section na lang ang capacitors.
like Tony said, there is no reason for it not to work... it is true that whatever DC at the outputs will be zeroed somewhat if they are of the same magnitude, if not, then there's gonna be trouble.
but try your suggested configuration and insert 1 ohm resistors at each amp's DC rails and you'll see that one of the amp will sink while the other will source current. sinking/sourcing current created unnecessary thermal buildup on the chips, this also means that even without music, current passes through your speakers.
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to avoid complications decided to use capacitors na rin. i read that for a bridged amp to work properly the gain of the non-inverting amp should be equal to the gain of the inverting amp, so i handpicked the 2k, 20k & 22k resistors and got the values up to the fourth digit sa digital meter. i even made a spreadsheet to calculate exact combos. some might react, overkill naman, but i found it better to prepare properly and minimize variables. like they say, measure twice and cut once. ;)
settled for 10.52 gain per amp on one channel and 10.48 on the other. can't get enough resistor combinations to match 4 gains equally. bridged 2 pcs lm1875 per channel. hirap pala pagkasyahin 8 resistors, 14 capacitors at 2 ICs sa 5x30 hole perforated boards! ;D
problems encountered:
1. over 25VDC at amp#1 out!!! -- hairline short between non-inverting input & +Vcc. really should have used a bigger board. or a pcb!
2. over 600mV dc at amp#2 -- di pala naconnect to ground yung isang non-inverting input.
3. no voltage at amp#3 & #4 -- naka-off pala ang power. ;D ;D ;D
so there... finished building my 40 wpc stereo amp this weekend. using 8 ohm speakers ramdam talaga ang power increase. using 4 ohm speakers halos same lang output as a single amp before it shuts down, dahil siguro sa protection circuit ng IC. yes i shouldn't have connected a 4-ohm speaker to this bridged amp, but curiosity got the better of me. test na rin how robust these ICs are. ;D :P
next project siguro would be to reconfigure and wire all 4 amps in parallel to test as sub amp. 8)
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each amp in the bridge will only see half the load impedance, but power supplied to the load is multiplied by 4, literally, because while one amp pushes, the other pulls. happy building sir.
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had the chance to pass by raon and bought a stereo 50k alps potentiometer from eleshop and after replacement the static was gone ;D
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had the chance to pass by raon and bought a stereo 50k alps potentiometer from eleshop and after replacement the static was gone ;D
Sir care to share which eleshop? How much? TIA!!!
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Sir care to share which eleshop? How much? TIA!!!
Eleshop is the name of the store, its located in a street parallel to Raon. Try to check out the where to buy parts thread, somebody may have posted the exact location/address.
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Eleshop is the name of the store, its located in a street parallel to Raon. Try to check out the where to buy parts thread, somebody may have posted the exact location/address.
yup sa raon bro...250php :)
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settled for 10.52 gain per amp on one channel and 10.48 on the other.
in my book, that is already perfect.....no need to lose sleep over a few tenths of gain..... ;D
what is more important is the offset voltages at the outputs of each amp....the closer you can get them to match....the better...
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i salvaged one 18-0-18 6A transformer from a jurassic cellular phone charger. will it give out 18x6=108VA or 36x6=216VA? sa pagkakaintindi ko kasi ang total voltage times current is the VA but still confused kasi may nakita akong 150 watt converter ang nasa loob 12-0-12 12A (144 or 288VA?) transformer.
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i salvaged one 18-0-18 6A transformer from a jurassic cellular phone charger. will it give out 18x6=108VA or 36x6=216VA? sa pagkakaintindi ko kasi ang total voltage times current is the VA but still confused kasi may nakita akong 150 watt converter ang nasa loob 12-0-12 12A (144 or 288VA?) transformer.
i judge the capacity of any transformer on the basis of its weight or physical size, then the internal reistance of the windings......
when it comes to transformers, bigger is better...... ;D
and to answer your question, 36x6=216VA,
again i am not too concerned about the current rating.....i will know when i see the traffo and measured its internal resistance what its capacity could be.....
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i judge the capacity of any transformer on the basis of its weight or physical size, then the internal reistance of the windings......
when it comes to transformers, bigger is better...... ;D
and to answer your question, 36x6=216VA,
again i am not too concerned about the current rating.....i will know when i see the traffo and measured its internal resistance what its capacity could be.....
i bought a 25-0-25V 8A, external measurements resemble a cube 3-1/4" per side, to power a pair of LM4780s for stereo biamping. do you think it's enough? my caps are 4,700uF. pag kapos i'll buy another one na lang and do monoblocks.
sana pala 3886 or 3875 na lang ginamit ko, ang hirap assemble ng 4780 sa protoboard, 1 lang nabuo ko maghapon! ;D
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i bought a 25-0-25V 8A, external measurements resemble a cube 3-1/4" per side, to power a pair of LM4780s for stereo biamping. do you think it's enough? my caps are 4,700uF. pag kapos i'll buy another one na lang and do monoblocks.
sana pala 3886 or 3875 na lang ginamit ko, ang hirap assemble ng 4780 sa protoboard, 1 lang nabuo ko maghapon! ;D
with unloaded rails of +/-35 volts, expect that to sag to about 27volts, your 4780 should be safe.....
are you bridging or operating them in parallel?....i see no issues if you want to operate them bridged.... ;D
about 10000ufd per rail caps should be okey...
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stereo biamping daw Tony...
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stereo biamping daw Tony...
oonga no.... ;D
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stereo biamping daw Tony...
oonga no.... ;D
ganun nga po. 1 chip (2 amps) per channel. ampA for low, ampB for hi. anything wrong with what i'm planning masters? would i be better off with bridged or parallel? ??? ??? ???
BTW I'll be using a TL072 based 2-way 2nd order active crossover. do you recommend the burr brown opa2244? or should i stick to TL072? both have the same pinouts and size but i'm not sure if they have the same function. nakakaengganyo kasi yung "burr-brown". i read the datasheets pero marami pa akong hindi maintindihan. :-[
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ganun nga po. 1 chip (2 amps) per channel. ampA for low, ampB for hi. anything wrong with what i'm planning masters? would i be better off with bridged or parallel? ??? ??? ???
BTW I'll be using a TL072 based 2-way 2nd order active crossover. do you recommend the burr brown opa2244? or should i stick to TL072? both have the same pinouts and size but i'm not sure if they have the same function. nakakaengganyo kasi yung "burr-brown". i read the datasheets pero marami pa akong hindi maintindihan. :-[
Nothing wrong with your plan sir, I just posted it for Tony's clarification. ;)
The TL072 is a dinosaur, like the NE4558. If you can't find an OPA2134, the venerable NE5532 should fit the bill quiet nicely. Also, please make sure that the 2 crossovers on your 2-way are phase linear so you won't have any problems with phasing. Good luck.
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thanks! i'm relieved, kala ko bad idea. :)
nabuo ko na 2nd 4780 but this time may tapping sound sa speakers, ang sound nya parang pinipitik yung woofer cone approx 2x per second. expected ko nga mas ok itong 2nd unit kasi mas malinis ang layout and it's placed farther from the power supply. dc offsets are 10 & 17 mV only. i'm stumped.
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check your grounding....without pictures it is hard to tell...
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i implemented star grounding with only a thin wire connecting the audio ground the star point. will try rerouting, halos dikit kasi yung input sa speaker out. will install 150 pF na rin across inputs. kainis dito pa sa last build ko may problem, sa bridged 1875 at sa unang 4780 simple lang mga problems. ubos na naman weekend ko nito! :P ;D
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bro saan ka bumili ng 4780 at magkano?
might built another gainclone amp this december ;D
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inorder ko sa supplier ng company namin 540 each. 300 daw yung 3886. suggest ko 3875 or 3886 na lang gamitin mo mas madali buoin at mas maganda heat dispersion.
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Mark, sounds like low frequency oscillation. May zobel network ka ginamit? Might as well check your feedback networks too while you're at it...
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i implemented star grounding with only a thin wire connecting the audio ground the star point. will try rerouting, halos dikit kasi yung input sa speaker out. will install 150 pF na rin across inputs. kainis dito pa sa last build ko may problem, sa bridged 1875 at sa unang 4780 simple lang mga problems. ubos na naman weekend ko nito! :P ;D
so how was your week-end? ;D
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so how was your week-end? ;D
happy po! nung inilipat ko ng pwesto ok na. ;D
apparently it's just picking-up noise from the dvdp smpsu underneath. nasa plywood base lang kasi.
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Some spare sleeping in my cabinet.
(http://i135.photobucket.com/albums/q148/t68kv/SDC10122.jpg)
(http://i135.photobucket.com/albums/q148/t68kv/lm4780kit.jpg)
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lm4870? magkano yung torroid at saang store?
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lm4780 nga bro tony. Yan parin yung toroid na nakadisplay dati kaya kinuha ko na "cherubim" ata name ng store. Nakuha ko ng 500. Nakatambak parin ngayon hehe. Kahit yung smps ko pang gainclone voltage hindi ko parin nagagamit.
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ilan VA yan toroid?
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hindi ko lang sure bro. Pero sa laki nya baka mga 150-200VA.
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Hi masters,
Kagagawa ko lang ng lm3875 eto yung ginamit kong schematic
(http://diyaudioprojects.com/Chip/Synergy-LM3875-Gainclone/LM3875-Gainclone-Chip-Amp-Schematic.png)
I used 14v-0v-14v trafo(110v main), KBPC3510 rectifier, 8pcs 2200uf 50v saka 100k generic pot
Ayos naman siya ok ang tunog sa classical, jazz, rnb... hindi ko nga lang gusto yung tunog sa pop saka rock masyado kasing dominant yung mid sound niya saka kakaiba yung bass niya.
Pag walang input sound, wala namang hiss at walang tunog kahit naka full yung volume.
Ang problem nga lang ay umaabot ng 800mv yung DC offset niya pag full volume (no input), pero pag naka off yung pot(100k ohm) 0mv naman...
Ano kayang modification yung gagawin ko para mawala yung dc offset?
Eto pala yung pics niya...
(http://i28.photobucket.com/albums/c247/jlester87/DIY%20Audio/PC300303.jpg)
Yung traffo pinahiga ko nalang hindi kasya eh... (panira yung green electrical tape hihih)
(http://i28.photobucket.com/albums/c247/jlester87/DIY%20Audio/PC300306.jpg)
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Ang problem nga lang ay umaabot ng 800mv yung DC offset niya pag full volume (no input), pero pag naka off yung pot(100k ohm) 0mv naman...
place a capacitor in series with the shunt resistor 680R, a 47ufd/16volts will be ok...
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add an input cap too while you're at it...
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place a capacitor in series with the shunt resistor 680R, a 47ufd/16volts will be ok
cge try ko, san po pala ilalagay yung +side ng capacitor?
add an input cap too while you're at it...
san po iseseries before pot or after?
Thanks! :)
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cge try ko, san po pala ilalagay yung +side ng capacitor?
san po iseseries before pot or after?
Thanks! :)
Yun + side dun sa side ng 680, yun - side dun sa ground.
Sa gitna nun pot and 220 ohms.
Btw, non-polar caps ba yun nakasabit sa bridge diode mo? Ano ang gamit nun sir?
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Yun + side dun sa side ng 680, yun - side dun sa ground.
Sa gitna nun pot and 220 ohms.
Btw, non-polar caps ba yun nakasabit sa bridge diode mo? Ano ang gamit nun sir?
Thanks for the info =)
4.7uf Non polar sir, nakita ko lang sa schematic ng nigc_kit... ok naman siya tumunog, nung polarized kasi yung ginamit ko pumangit yung tunog, tapos yung 0.1uf mylar sa apat na side ng rectifier medyo harsh yung tunog...
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Ah ok po sir. Sige good luck and congrats on your amp.
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Hi masters,
Kagagawa ko lang ng lm3875 eto yung ginamit kong schematic
(http://diyaudioprojects.com/Chip/Synergy-LM3875-Gainclone/LM3875-Gainclone-Chip-Amp-Schematic.png)
sir have you tried implementing capacitance multiplier in the PSU section,? I have used it in my past gainclone project( LM1875, TA8216H, TDA1521...to name a few) and my past class A(room heater ;D) solid state obsession( Hiraga, JLH, Delpiane). Imho a big difference in sonic performance, plus it cleans totally the hum that's been bugging you. Just go to Rod Elliots site for schematics & added info
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the selling point of gainclones is high PSRR, thus ripples from the power supply is not really a problem, some even swear that highish capacitance on the psu is more of a liability, bumabagal daw yung bass.... ;D
to me it wouldn't hurt to get a very clean psu if you can get it..... ;D
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to me it wouldn't hurt to get a very clean psu if you can get it..... ;D
agree 100% sir :)
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bakit kaya sir hindi nagvivibrate yung speakers ko pag nag babass? kakaiba yung galaw niya pag may bass umaangat lang yung speaker cone...
hindi ko pa kasi nagagawa yung suggestions niyo, nasira kasi yung soldering iron ko, wala pa time para bumili... saka pag nagka time baka palitan ko nalang ng lm3886 para umayos yung bass...
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may dc offset yan sir :)
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nilagyan ko na po ng 47uf sa 680r, 4mv-6mv nlng ang max dc offset niya... ok narin yung bass niya... saka pansin ko parang lumakas siya? thanks!
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nilagyan ko na po ng 47uf sa 680r, 4mv-6mv nlng ang max dc offset niya... ok narin yung bass niya... saka pansin ko parang lumakas siya? thanks!
the lesson you learned here is not unique, it is applicable to all other amps..... ;)
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sir bat pala medyo masakit sa tenga yung tunog nung nilagyan ko nung capacitor? walang tatak kasi yung nilagay ko... tinanggal ko nalang tapos nilagyan ko ng after ng pot 4.7uf np + 22k resistor to ground... Ang result bumalik sa dati yung tunog (less harsh) tapos constant 0.12V yung dc offset niya...
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try mo rin lagyan ng input capacitor...
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Good Day mga GC Masters. Regarding lang po sana sa GC Afturburner. I was googling a schematic for an LM1875 Afterburner and I saw this one:
http://tecluv.com/diy-audio-power-amplifier-lm1875-bridge-2sa1943-2sc5200-100-watt-with-circuit-diagram-and-pcb-layout/
Now, comparing to Master JojoD's schematic, yung base po ng transistor is naka loop sa output ng chip whereas this one, naka tap sa +/- power supply rails. Medyo nag-duda po ako sa schematic kasi medyo malabo yung grammar e. ???
Pwede ko po pa verify sa mga Masters kung valid yung schematic? Nagawa ko na po kasi to kaso takot ako i-test baka masira yung sub driver ko.
Also, pano po malalaman or mate-test na ok yung circuit? Same pa din po ba yung DC offset nito sa LM1875 GC? Baka po kasi masira ko yung subwoofer ko pag ni-hook ko diretso dito e.
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(http://tecluv.com/wp-content/uploads/2010/09/DIY-Audio-Power-Amplifier-LM1875-bridge-2SA1943-2SC5200-100-Watt.jpg)
gagana po yan sir, consider r4 which is effectively connected to vt1's base and emitter, once ic1(1875) conducts, current will flow at r4, once a voltage of roughly 0.65V is present across r4 this will turn on vt1 which will take over the large current that the load requires. the cycle is the same for r5 and vt2. with r4 and r5 values, vt1 and vt2 will take over at approximately 650mA of current draw from the chip.
hope this helps
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valid yung schematic
the output trannies are in common emitter config...jojo's are emitter followers(common collectors)......
while the circuit works by amplifying the current draw of the 1875 chip, i have reservations, the output trannies add to the open loop gain of the 1875 which has more than enough open loop gain......
maybe it is a matter of preference but i think jojo's circuit is more stable, yours is prone to instability imho....
but since the circuit is so simple, you can try and report your findings here...good luck....
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@Sir JojoD: Thanks Sir!!! Will try to fire this up tomorrow, hopefully hindi maging fireworks display. . .
@Sir TonyT: Sige po, will try both configs and see if which sounds better. Also, pasensya na po, am really new on DIY Hi-Fi Audio, marunong lang po akong maghinang, magbasa ng capacitor at resistor values, at schematics but I really don't know the science and terms behind it. . . Ibig po bang sabihin ng instability e yung oscillation? or hum?
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Ibig po bang sabihin ng instability e yung oscillation? or hum?
oscillation, minsan low frequency or motorboating, mas mahirap pag high frequency yung hindi mo marinig pero makikita pag ginamitan ng scope.......mahabang talakayan itong instability issues sa mga amplifiers...
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@Sir JojoD: Thanks Sir!!! Will try to fire this up tomorrow, hopefully hindi maging fireworks display. . .
Good luck sir! ;)
Whatever happens, gumana man o sumabog, keep DIYing!!! 8) 8) 8)
Ang importante po may natutunan, pag gumana pwede ulitin, pag sumabog wag na uulitin pero alamin kung bakit sumabog... ;D ;D ;D
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oscillation, minsan low frequency or motorboating, mas mahirap pag high frequency yung hindi mo marinig pero makikita pag ginamitan ng scope.......mahabang talakayan itong instability issues sa mga amplifiers...
+1, dami factors to consider. Before, I destroyed several output devices because of hf oscillations, di ko na kasi madinig akala ko walang oscillation. :(
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Yung nakatambak kong JVC SU-A97, NEC UPC1188H chipamp pala yung laman... ayun kaya pinalitan ko ng lm3875, mas ok na ang sound niya w/any kind of music compared sa minimalist gainclone na ginawa ko. :)
(http://i28.photobucket.com/albums/c247/jlester87/DIY%20Audio/JVC%20Surround%20Processor/P1010090.jpg)
(http://i28.photobucket.com/albums/c247/jlester87/DIY%20Audio/JVC%20Surround%20Processor/P1010087.jpg)
(http://i28.photobucket.com/albums/c247/jlester87/DIY%20Audio/JVC%20Surround%20Processor/ae1a9769.jpg)
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@Sir JojoD: Thanks Sir!!! Will try to fire this up tomorrow, hopefully hindi maging fireworks display. . .
@Sir TonyT: Sige po, will try both configs and see if which sounds better. Also, pasensya na po, am really new on DIY Hi-Fi Audio, marunong lang po akong maghinang, magbasa ng capacitor at resistor values, at schematics but I really don't know the science and terms behind it. . . Ibig po bang sabihin ng instability e yung oscillation? or hum?
Gumagana na ba sir? plan ko din sana gumawa niyan,. pang subwoofer sana. thanks!
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Yung nakatambak kong JVC SU-A97, NEC UPC1188H chipamp pala yung laman... ayun kaya pinalitan ko ng lm3875, mas ok na ang sound niya w/any kind of music compared sa minimalist gainclone na ginawa ko. :)
(http://i28.photobucket.com/albums/c247/jlester87/DIY%20Audio/P1010090.jpg)
(http://i28.photobucket.com/albums/c247/jlester87/DIY%20Audio/P1010087.jpg)
(http://i28.photobucket.com/albums/c247/jlester87/DIY%20Audio/P1010078.jpg)
yon pa rin ang psu? congrats....
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yon pa rin ang psu? congrats....
Opo, yung nasa picture po...maliit lang po yung psu niya... 120v 21.5v rectified
(http://i28.photobucket.com/albums/c247/jlester87/DIY%20Audio/JVC%20Surround%20Processor/P1010087.jpg)
yung chip lang po yung pinalitan ko, eto na siya...
compared sa minimalist gainclone, naging warmer yung sound nito pero medyo nawala yung detail sa highs, (dati kasi ok ang highs ng minimalist gainclone ko pero manipis yung mid at bass, parang tv sounding). Yung tunog nito parang jvc na microcomponent ang dating.
Saka pala kahit walang tugtog medyo warm yung heatsink niya (hindi kaya nag ooscillate? or mainit lang yung transistor na nakakabit din sa heatsink?), yung minimalist gainclone ko kasi dati kahit nagpapatugtog ng mahina, walang kainit init...
(http://i28.photobucket.com/albums/c247/jlester87/DIY%20Audio/JVC%20Surround%20Processor/2eef3418.jpg)
(update: ginawa ko yung reference schematic ng lm3875 at nilagyan ng input cap, nawala na yung init pag idle and all I can say is WOW! eto na ata yung sinasabi nilang magic ng gainclone)
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needed help about LM3886T single supply schematic, cant find a simple one on the net, the one provided by National has an extra transistor and without the output capacitor. Will be using these as a replacement for the power amp module of my friend's vintage Sansui Model2000 receiver which has a single rail supply of 70VDC.
Thanks in advance
:)
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efren,
you can look here for ideas.....http://www.diyaudio.com/forums/chip-amps/75491-gainclone-newbie-help-lm3886.html
working on a single rail, you will need a 2200ufd/50volts dc coupling capacitor on the output terminal.....then you need to create a virtual ground for the input resistor, a 22k, these can be made from a series string of about 10K 1watt resistors, bypassed with a 10ufd/50v capacitor...the junction then becomes a "0" volt reference for the ouput.....you also need an input cap...
(http://diyaudioprojects.com/Chip/LM3886_CA/F01-LM3886-chipamp.png)
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oopps I missed the output caps by NS in their apps notes, despite my 250 reading glasses, sorry for that ;D
so the transistor can be just substituted with resistor strings from B+ and ground going to pin7, and shunting that pin with 100uF cap to ground?
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I need a little more time with these downloaded file from NS, got to be careful with these chips ;D
will update as soon when things are ok.
thanks sir Tony. ;)
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guys ano magandang diy tube buffer para sa gc? the simpliest sana since never pa ako nkapag try mag diy using tubes :-\
btw up to now buhay pa si gc ko, palit bagong knob at nilagyan ko ng 3m rubber bump on sa ilalim to act as stands :D
(http://i192.photobucket.com/albums/z21/blackmoly_photos/audio%20bliss/DSCF4530.jpg)
(http://i192.photobucket.com/albums/z21/blackmoly_photos/audio%20bliss/DSCF4532.jpg)
thanks! :)
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oopps I missed the output caps by NS in their apps notes, despite my 250 reading glasses, sorry for that ;D
so the transistor can be just substituted with resistor strings from B+ and ground going to pin7, and shunting that pin with 100uF cap to ground?
yes, 2 x 10k resistor string should do it, and yes, pin7 goes to the virtual ground as well....
the output cap is required since the output pin 3 will have 35volts.....
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guys ano magandang diy tube buffer para sa gc? the simpliest sana since never pa ako nkapag try mag diy using tubes :-\
btw up to now buhay pa si gc ko, palit bagong knob at nilagyan ko ng 3m rubber bump on sa ilalim to act as stands :D
(http://i192.photobucket.com/albums/z21/blackmoly_photos/audio%20bliss/DSCF4530.jpg)
(http://i192.photobucket.com/albums/z21/blackmoly_photos/audio%20bliss/DSCF4532.jpg)
thanks! :)
cathode followers using 6922, 6dj8, 6h23, e88cc tubes, you can use the existing rails of your gainclones to supply the tubes, all you need then is a filament supply and then you are go......
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yes, 2 x 10k resistor string should do it, and yes, pin7 goes to the virtual ground as well....
the output cap is required since the output pin 3 will have 35volts.....
One thing I notice on the single supply rail from National Semiconductor apps notes is that pin5 is not indicated on the diagram. only pin1 is tied to B+, unlike in the dual rail, pins 1&5 are indicated connected in the B+.
Should it be this way or just a typo error on their part, because pin config from NS indicate that pin5 is also B+. ???
Thanks again sir :)
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just a clarification question sir Tony, in the single rail topology of LM3886, pins 7&9 are both connected to virtual ground right? So is it ok not to implement the 3904 transistor, just a string of 2 resistors from B+ & Gnd,
the point where they meet is the virtual ground, also from that point is a capacitor shunted to ground.
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yes, this should do....
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just a clarification question sir Tony, in the single rail topology of LM3886, pins 7&9 are both connected to virtual ground right? So is it ok not to implement the 3904 transistor, just a string of 2 resistors from B+ & Gnd,
the point where they meet is the virtual ground, also from that point is a capacitor shunted to ground.
bossing how's the project? did it work?
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bossing how's the project? did it work?
change of plans, I used TA8216H (Toshiba), the owner quite happy with it, used a Zener in a series pass tranny to bring down 70V rail to 24V as required by TA8216H ;D
I still have those LM3886 for future gainclone projects :D
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hehe... ako naman may junk amp, totally fried ang board pero buo psu. +/-66 ang rail voltage. i tweaked an AVReg to put out 130 volts and plugged the amp, +/-36 volts na ang output sakto sa gainclone. ;D exclusive partners na yung avr at amp ngayon. :P
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^pwede mo gamitin yung LM4702.......
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^kailangan pa yata nyan ng output transistors, gusto ko simple lang. saka happy na ko sa 60wpc for my bedroom. may alalay naman na 120w sub for movies. :)
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woot woot, ano yan ha? ;D ;D ;D
ano yun gainclone na kailangan ng output transistor?
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Sir Jojo,
Pwede kaya ito for lm3886t and 2sa1943/2sc5200?
Meron kasi akong isang working channel ng lm3886 na very similar ang schematic. mukhang pwede kong pagtestingan. +-35 ang supply, around 32 ang gain.
Ilang watts yung 1R and .22R?
Rusty
I can't help but notice that there's been a surge of DIYers who want to build gainclones for their HT and Audio systems. The basic gainclone is simple and easy to build so it's the perfect project for the beginner with mods and tricks as your skill progresses.
A few years ago, National published a white paper showing how to scale up their chips for more power handling, and so the birth of the gc bridge, gc paralleled, and gc bridged-paralleled. These configurations have paved the way for gainclones to power sub woofer systems. Some problems like current sinking/sourcing have been easily solved by active DC servo but this complicates everything and scares the heck out of a builder. ;D But a single chip is not just enough to power a sub, and more often it goes into protection (sPiKe for National chips) if not completely destroying the chip.
Not too long ago, Circlotron of diyAudio posted a gainclone "afterburner", more technically known as a current dumping circuit. With these modifications, all you need is a single chip and a couple of power transistors to build a sub amp.
I have studied and worked around with it many times (whenever I have the time) and so in the spirit of sharing, I drew this schematic for those who may want to try it out.
(http://img.photobucket.com/albums/v70/jojod818/JD%20Labs/gcx.jpg)
Notes:
1. Tons of choices for the power transistors are available, just pay attention to it's collector current and collector-emitter voltage.
2. Traditional power supply decoupling still applies (not shown in the schematic).
3. Output power transistors operates in Class B so suitable applications would be for powering a sub.
Disclaimer:
1. I would not be responsible for any damages you or your gears may incur. So safety first!
2. I just want to share ideas, so please don't don't blame me if it doesn't work.
PS:
Mine has been working for years now, powering a 12 inch sub. :P
(http://img.photobucket.com/albums/v70/jojod818/JD%20Labs/gcxactual.jpg)
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(http://img.photobucket.com/albums/v70/jojod818/JD%20Labs/gcx.jpg)
question din masters pwede ba different supplies, say +/-20V for an LM1875 and +/-66 for the transistor pair? if i want to decrease the load of the chip, tama ba analysis ko na i need to increase 1R? to what value?
mentioned voltages are available sa "fried" amp ko but i presume the lower voltages are low current only so the chip should have as little load as possible.
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Pwede kaya ito for lm3886t and 2sa1943/2sc5200?
pwede...
Ilang watts yung 1R and .22R?
5 watts.....
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question din masters pwede ba different supplies, say +/-20V for an LM1875 and +/-66 for the transistor pair? if i want to decrease the load of the chip, tama ba analysis ko na i need to increase 1R? to what value?
if you do that, your output voltage swing is limited by the +/-20 volts, might as well use that also for the transistor pair....the 1R is there to bias the transistor pair into a classB operation, a 1amp into that 1R resistor develops a 1volt peak voltage or 0.7rms, drives these trannies hard........
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ganun pala... thanks! guess i'll have to stick with my 130V option. ;D
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Sir Jojo,
Pwede kaya ito for lm3886t and 2sa1943/2sc5200?
Meron kasi akong isang working channel ng lm3886 na very similar ang schematic. mukhang pwede kong pagtestingan. +-35 ang supply, around 32 ang gain.
Ilang watts yung 1R and .22R?
Rusty
Pwedeng pwede sir! Pero kung i-point to point mo ingat lang kasi maselan sa stray oscillation sir. Also, reduce your gain to about 22, supply looks good.
I prefer to use the Panasonic 3W flame proof resistors but the 5W Raon types should also work for prototyping needs.
Good luck and Godspeed!
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(http://img.photobucket.com/albums/v70/jojod818/JD%20Labs/gcx.jpg)
question din masters pwede ba different supplies, say +/-20V for an LM1875 and +/-66 for the transistor pair? if i want to decrease the load of the chip, tama ba analysis ko na i need to increase 1R? to what value?
mentioned voltages are available sa "fried" amp ko but i presume the lower voltages are low current only so the chip should have as little load as possible.
Mark,
Stick with the +/-35V max, but if you stack several output devices then you can push it to about +/-40V safely even with low impedance loads.
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woot woot, ano yan ha? ;D ;D ;D
ano yun gainclone na kailangan ng output transistor?
LM4702, gusto mo ng sample? ;D
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LM4702, gusto mo ng sample? ;D
Sabi ko na nga ba... matindi yan scalable! 8)
Di nga meron? Tinatanong pa ba yan... :D
Have you made one? Problema na naman nito kung flat pack o to3 package ang gagamitin hehehe... ;D
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^sige iwan ko kay Lingling or Amy sa golden mars para dun mo na lang kunin.....pwede rin mosfet ang gamitin... ;D
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^sige iwan ko kay Lingling or Amy sa golden mars para dun mo na lang kunin.....pwede rin mosfet ang gamitin... ;D
uy pwede yan, kailan ka ba punta dun? no rush naman at busy pa din pero sana magkatiyempo tayo para maka kain (or inom ;D) naman tayo hehehe... :D
wow sakto yan meron ako padating IRF240/IRFP9240 pairs... 8)
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pwede yang mosfets na yan, hanapin mo na lang sa national website yung application notes...
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alright, outstanding...
thanks tony!
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Di ko pa nasusubukan itong lm3886t + 2sa1943/2sc5200 dahil nagamit ko sa SymAsym 5.3 yung 2sa1943/2sc5200. Hindi chipamp ito pero meron bang iba dito na gumawa din nung SymAsym from DIYAudio? Currently listening to mine ;D Wala pang casing-nakapatong lang sa plywood.
http://web.telecom.cz/macura/symasym.html (http://web.telecom.cz/macura/symasym.html)
Sir Jojo,
Pwede kaya ito for lm3886t and 2sa1943/2sc5200?
Meron kasi akong isang working channel ng lm3886 na very similar ang schematic. mukhang pwede kong pagtestingan. +-35 ang supply, around 32 ang gain.
Ilang watts yung 1R and .22R?
Rusty
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Di ko pa nasusubukan itong lm3886t + 2sa1943/2sc5200 dahil nagamit ko sa SymAsym 5.3 yung 2sa1943/2sc5200. Hindi chipamp ito pero meron bang iba dito na gumawa din nung SymAsym from DIYAudio? Currently listening to mine ;D Wala pang casing-nakapatong lang sa plywood.
http://web.telecom.cz/macura/symasym.html (http://web.telecom.cz/macura/symasym.html)
Hi Rusty,
Congrats on your symasym build, it's a wonderful little amp imo. Although the absence of a constant current mirror that feeds the top of the ltp turns off most enthusiast it is the low distortion and simplicity that attracts most builders.
Beware of oscillations when using different output devices though. The 5200/1943 flat packs are devilishly oscillation magnets in wide bandwidth amplifier designs, unless you properly tame them within your feedback loop, you are bound to oscillation. I once had two pairs lasting for only a few seconds before magic smoke appeared. That was my bad, of course. ;D
Cheers
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Thanks. Swerte naman ako at naka-dalawang channel na ako without seeing the magic smoke:) DC offset at around 20+mv, Idle current at around 150ma.
Di ko actually naiintindihan ang specifics ng design na ito. Sinunod ko lang ang instructions nung designer:)
I've been using this amp for nearly a week. Sounds great to me with the help of Pilyo amp4v2 from 50hz and below. Possible kaya na nagoocillate ito nang di ko alam? Masyadong maliit yung heatsinks nito(5"x4"x1") pero may nakatutok na 120mm computer casing fans
Rusty
Hi Rusty,
Congrats on your symasym build, it's a wonderful little amp imo. Although the absence of a constant current mirror that feeds the top of the ltp turns off most enthusiast it is the low distortion and simplicity that attracts most builders.
Beware of oscillations when using different output devices though. The 5200/1943 flat packs are devilishly oscillation magnets in wide bandwidth amplifier designs, unless you properly tame them within your feedback loop, you are bound to oscillation. I once had two pairs lasting for only a few seconds before magic smoke appeared. That was my bad, of course. ;D
Cheers
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Di ko actually naiintindihan ang specifics ng design na ito. Sinunod ko lang ang instructions nung designer:)
I've been using this amp for nearly a week. Sounds great to me with the help of Pilyo amp4v2 from 50hz and below. Possible kaya na nagoocillate ito nang di ko alam? Masyadong maliit yung heatsinks nito(5"x4"x1") pero may nakatutok na 120mm computer casing fans
ask ka lang at sisikapin nating masagot...... ;D
about oscillation, there is always that possibility but it seems that this is a well designed amp, you can see the oscillations on the scope if ever, but i doubt that it will happen to you... ;)
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Thanks. Swerte naman ako at naka-dalawang channel na ako without seeing the magic smoke:) DC offset at around 20+mv, Idle current at around 150ma.
Di ko actually naiintindihan ang specifics ng design na ito. Sinunod ko lang ang instructions nung designer:)
I've been using this amp for nearly a week. Sounds great to me with the help of Pilyo amp4v2 from 50hz and below. Possible kaya na nagoocillate ito nang di ko alam? Masyadong maliit yung heatsinks nito(5"x4"x1") pero may nakatutok na 120mm computer casing fans
Rusty
Since sinunod mo naman yun cautions para dun sa 5200/1943 trannies then I think you're on the safe side.
Medyo maliit nga yun heatsink mo, but if you get stable temps with an Iq of 150mA then you're probably just about at the borderline. Kung malakihan mo pa mas ok sana to eliminate the fan.
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may nakagawa na po ng LM4780? any reviews?
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may nakagawa na po ng LM4780? any reviews?
reviews are all over the net, its basically 2 3886 chips in one. http://home.mira.net/~gnb/audio/lm4780.html
my suggestion: don't use it if you don't have a pcb. it'll take you a whole weekend if you use veroboard as i did. :P
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you need something like this:
(http://i5.photobucket.com/albums/y155/leoman53/gainclones/CIMG0326.jpg)
btw, markrenz, mind telling where you got your chips and how much? i have 8 of these lying around...
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wow...astig.. plan ko gawin 5.1.. may samples sa national na site kaso may handling and shipping fee. undecided pa kung ku2ha ako. pero kung compare ang price sa farnell, mas cheaper.
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may soft copy po kayo ng pcb nyan?dual layer or single lang?
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may soft copy po kayo ng pcb nyan?dual layer or single lang?
galing dito ung board: http://www.audiosector.com/lm4780.shtml
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btw, markrenz, mind telling where you got your chips and how much? i have 8 of these lying around...
mas mura 1 4780 kaysa 2 3886. a few pesos saved pero a lot of time spent. >:(
inorder ko sa supplier ng company namin 540 each. 300 daw yung 3886. suggest ko 3875 or 3886 na lang gamitin mo mas madali buoin at mas maganda heat dispersion.
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galing dito ung board: http://www.audiosector.com/lm4780.shtml
dual layer pla :D...
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mas mura 1 4780 kaysa 2 3886. a few pesos saved pero a lot of time spent. >:(
[quote}inorder ko sa supplier ng company namin 540 each. 300 daw yung 3886. suggest ko 3875 or 3886 na lang gamitin mo mas madali buoin at mas maganda heat dispersion.[/quote]
hindi po ba halos parehas lang ang no of components nya? parang mas prefer ko kasi ung lm4780. kasi flexible xa. pde mo ibridge or iparallel or stereo mode in a single chip. :D dami pde gawin :D kung sa heat naman, pde naman na tutukan xa ng fan. :D
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lm4780 - 4pcs $16.22
lm3886t - 2pcs $17.66
:D
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hindi po ba halos parehas lang ang no of components nya? parang mas prefer ko kasi ung lm4780. kasi flexible xa. pde mo ibridge or iparallel or stereo mode in a single chip. :D dami pde gawin :D kung sa heat naman, pde naman na tutukan xa ng fan. :D
go ahead then. it's your build. wala naman pumipigil sa yo. good luck!
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[quote}inorder ko sa supplier ng company namin 540 each. 300 daw yung 3886. suggest ko 3875 or 3886 na lang gamitin mo mas madali buoin at mas maganda heat dispersion.
hindi po ba halos parehas lang ang no of components nya? parang mas prefer ko kasi ung lm4780. kasi flexible xa. pde mo ibridge or iparallel or stereo mode in a single chip. :D dami pde gawin :D kung sa heat naman, pde naman na tutukan xa ng fan. :D
this is a common mistake in the hobby, always take into account the amount of "contact area" per Watt.
tapos gusto mo pa i-bridge or i-parallel yun 4780? you're asking for thermal problems there sir. kahit tutukan mo pa ng fan. why not go with mark's advice, 2 LM3886 in a bpa100 or 4 in a bpa 200. if your ambitious, make 2 boards with 4 paralleled 3886, then bridge that and you can go as low as 2 ohms load before sPike kicks in.
this is just my advice, take it with a grain of salt or do as you please. always remember - once the Magic Smoke escapes from a chip, it's impossible to put it back in. ;)
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mas maganda na 2chips na LM4780 tapos 3 lm3886?
2chips lm4780 will use for front(L/R)/surround(L/R)
2chips lm3886 will use for sub
1chip lm3886 will use for center
ganito na lang po..anu comment nyo mga sir?
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dapat sa sub 8pcs... :D :D :D
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dami..haha
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may mabait na nagbigay sa akin ng xiang sheng 708a tube preamp/ headphone amp ;D ganda pala pag naka tube preamp si lm3875 :D
(http://i192.photobucket.com/albums/z21/blackmoly_photos/audio%20bliss/DSCF5613.jpg)
naging mas malambing ang female vocals :o
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Hello mga master,
May tanong lang po ako. I made a diy active crossover and subsonic filter based on rod elliot's schematics. Di ko pa matest dahil wala pa akong +-15 na psu. I was planning to tap into the GC amp's psu right after the caps(+-35) using lm7815 and lm7915. Ang problema is: although +15v ang lumalabas sa output ng lm7815, hindi -15v ang lumalabas sa output ng lm7915 kundi -26. Binasa ko naman ang datasheet ng lm7915, G-I-O(1,2,3) ang pin config. May mali ba akong ginawa? o palpak itong 3 lm7915 na nabili ko? (btw, sinukat ko ang voltage between + and - ng lm7815/lm7915 circuit, 41v.)(http://i29.photobucket.com/albums/c286/rustyns/xoverpsu/7815psu.gif)
Thanks
Rusty
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^can you post pictures?
either me mali ka sa iring or defective you regulator chip, saan mo binile yung regulator?
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pin assignment of 7915
pin 1 - gnd
pin 2 - input
pin 3 - output
tama ba? :D
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^can you post pictures?
either me mali ka sa iring or defective you regulator chip, saan mo binile yung regulator?
Sir Tony,
Ang una kong assumption was mali yung wiring ko. So sinubukan ko i-isolate ang problem. Nagtap ako ng isang wire from ground ng transformer at isa pang wire sa negative ng psu. Sinukat ko ang voltage: -35. Kinabit ko yung ground sa pin 1 ng 7915 and yung negative sa pin 2 ng 7915. sinukat ko ang voltage between pin 1 and pin 3: -26 talaga.
Sinubukan ko the same thing sa 7815, isang wire from ground and isang wire from positive ng psu. voltage:+35. Kinabit ko yung ground sa pin 2 ng 7815 and yung positive sa pin 1 ng 7815. voltage between pin 2 and pin 3: +15.
Both itong 7815 and 7915 sa DEECO commonwealth binili.
Thanks.
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^you got a defective lm7915.....best to buy from Alexan...
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you're pushing it to the limit. review the datasheet, absolute max voltage is 35 volts. try to insert a 10 ohm 1 watt resistor before each reg input. or install a small psu na lang. even a 200 mA transformer is enough.
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^yup, an input limiting resistor or even 5watt zener diodes, about 04.7 ~ 12volts in series with the inputs really helps..... ;)
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I would go with the dropping resistor or zener since you already have most of the parts. Or kung ambitious, capacitance multiplier or series pass muna before the 3-terminal regs pero kung sa sub mo lang gagamitin yan ok na yun resistor. ;D
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you're pushing it to the limit. review the datasheet, absolute max voltage is 35 volts. try to insert a 10 ohm 1 watt resistor before each reg input. or install a small psu na lang. even a 200 mA transformer is enough.
Thanks sa suggestions sir. Hindi nagwork yung pagdagdag ng resistors. Try ko next yung maliit na transformer with 7815 and 7915 from alexan.
Rusty
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you're pushing it to the limit. review the datasheet, absolute max voltage is 35 volts. try to insert a 10 ohm 1 watt resistor before each reg input. or install a small psu na lang. even a 200 mA transformer is enough.
Sinubukan ko 220 ohm instead of 10 and it worked. Many thanks! :)
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Sinubukan ko 220 ohm instead of 10 and it worked. Many thanks! :)
Remember to put an electrolytic capacitor (note the polarity) after that 220 ohm resistor.
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Sorry for OT and for my ignorance
Just wanted to know the difference between the gainclone vs Dayton APA? anyone who tried to compare this two in SQ?
please i need feedback....
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Mga Sirs,
Matanong ko lang po uli kung saan ako makabili nang LM 3875 sa Raon or sa Cubao.
Eh, try ko rin na gumawa po sana. Tulungan niyo sana ako. Puwede rin niyo akong ma contact
sa e mail: [email protected] or [email protected] ...Salamat po.
Vimikay
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sa newport electronics, sa raon, nasa 350 ang isang isa....
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Mga Sirs, ...Malaking pasensiya po sa kulit ko . Wala po silang stock daw na LM 3875, noong isang linggo nang nagtanong po ako sa Newport. Bigay niyo po kung mayroon pa po kayong alam na nagbibinta nang LM 3875 sa Cubao or sa Raon. Gusto ko rin pong masubukan makagawa nang gainclones na ampli...
Salamat uli sa inyo po... Vimikay
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try mo alexan (raon) bro, dun ako dati bumili :)
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Mga Sirs, ...Malaking pasensiya po sa kulit ko . Wala po silang stock daw na LM 3875, noong isang linggo nang nagtanong po ako sa Newport. Bigay niyo po kung mayroon pa po kayong alam na nagbibinta nang LM 3875 sa Cubao or sa Raon. Gusto ko rin pong masubukan makagawa nang gainclones na ampli...
Salamat uli sa inyo po... Vimikay
try mo sa alexan, dun ko nabili yung sakin less than 300 yung price pero last year pa yun...
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try mo rin sa Liamson or Eleshop baka meron....
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Mga Sirs,
Baka mayroon po kayong LM 3875 diyan na hinde niyo na gagamitin ay ibinta niyo na sa akin.
Balak ko kasi ay bibili nang mga apat(4) na piraso. Sakali lang ay bilhin ko na lang po sa inyo. Dating ko
po diyan sa Manila ay mga 28 nang December 2011 galing Bohol. At puwede po kayong mag email sa akin:
[email protected] or [email protected]. At puntahan ko po kayo at magkita tayo sa Metro Manila or malapit. Salamat po sa inyo at sana makagawa din po ako nang ampli ko na gainclone. Excited na nga ako.
Regards at Merry Christmas and a Happy New Year sa inyong lahat.
Alfie
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Mga Sirs,
Thanks a lot for your assistance. I was able to buy in Alexan(Raon) and
I will be starting to assemble my LM3875 soonest.
Again thanks a lot.
Regards and Merry Christmas and Happy New Year,
Alfie
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mga bossing, would like to solicit additional feedback on this chipamp design from diyaudio. thinking of a gainclone project to pass time.
http://www.diyaudio.com/forums/chip-amps/54571-my-audiophile-lm3886-approach.html (http://www.diyaudio.com/forums/chip-amps/54571-my-audiophile-lm3886-approach.html)
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mga bossing, would like to solicit additional feedback on this chipamp design from diyaudio. thinking of a gainclone project to pass time.
http://www.diyaudio.com/forums/chip-amps/54571-my-audiophile-lm3886-approach.html (http://www.diyaudio.com/forums/chip-amps/54571-my-audiophile-lm3886-approach.html)
gainclones are good sounding amps, jojod has sold plenty of those here, he calls it babyG....
if you want kits this a good place to get it....http://www.audiosector.com/
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mga bossing, would like to solicit additional feedback on this chipamp design from diyaudio. thinking of a gainclone project to pass time.
http://www.diyaudio.com/forums/chip-amps/54571-my-audiophile-lm3886-approach.html (http://www.diyaudio.com/forums/chip-amps/54571-my-audiophile-lm3886-approach.html)
unless you fully understand mauro's design, you're better off with a basic, proven gainclone.
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thanks sir tonyt
what do you mean sir markcrenz? mahirap gawin yung kit ni mauro?
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input op-amp ang pinagkaiba, the LM318 is a very fast op amp with high slew rate, are you making the board yourself?
the3886 then is used as a unity gain power stage......bandwidth is maximum at unity gain...
hmm....maybe it is good to find out how it sounds.....go ahead and do it..... ;D
suggestion, provide a socket for LM318 so you can roll op-amps....
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based dun sa thread sir tony merong kits being offered. i thought nakarating dito sa pinoydvd kaya nagsosolicit ako ng feedback.
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if you haven't made any, I suggest you start with the basic. anything with a gain of ~20 won't hurt your bandwidth unless you have an oscilloscope built-in on your ears. :D
or you can redo it and use an OPA637 with a minimum gain of ~5. the tricky/freaky thing about that design is decoupling, use a Salas shunt reg on the opamps if you're feeling a bit adventurous.
friendly advice, the opamp is direct-coupled and inside the feedback loop so watch out for input offsets or you'll end up with a constant DC output up your ass. ;)
cheers!
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sir Jojo do you offer your babyG as kits also?
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sir Jojo do you offer your babyG as kits also?
Unfortunately, I intentionally do not offer it as a kit sir.
You can ask tony if he has some spare from the group buys he joined in. There will also be a range of new boards available at diyAudio Store in the future.
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i have no boards to sell, sorry...
jojo kailan nga pala magiging available yan sa diystores?
ano basa mo kay senor Carlos, para nga bang namamaalam na? ???
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thanks sa mga inputs mga sirs.
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i have no boards to sell, sorry...
jojo kailan nga pala magiging available yan sa diystores?
ano basa mo kay senor Carlos, para nga bang namamaalam na? ???
some of the guys are still on holiday mode, napasarap yata... pero I'm pushing them to haul ass at madami na ang naghihintay ng mga new boards eh...
wag naman sana siya namamaalam, laki ng contribution niya eh. baka dahil doon sa Blameless, though I'm still seriously considering to give that amp a place in the store. diba mas ok nga yun para madami tayo variety to choose from.
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parang me tampo ano? sure the more variety to chose from, the better, panalo ang end user....
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sa symasym pa lang nakakahalata na kami, kaya lang may consensus na kailangan sundin so hindi naman natuloy. pero ok naman sila na madami ang variety to choose from kaya lang maingat sa pagpili.
parang pagiging mod lang yan, di ka pwede mag apply, you have to be picked. ;D
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gusto ni senor Carlos maging mod? :D
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hindi, si Andrew ang gustong gusto :D hahaha!
si Charlie ang gusto maisama yun mga designs niya sa store...
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hindi, si Andrew ang gustong gusto :D hahaha!
si Charlie ang gusto maisama yun mga designs niya sa store...
oo nga, kung umasta sya parang mod, kaya nga nag post ako dun, ninominate ko sya..... :D :D :D
@squatt3r,
eto yung gainclone building thread sa kabila, posted by efren, http://www.electronicslab.ph/forum/index.php?topic=29231.100
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oo nga, kung umasta sya parang mod, kaya nga nag post ako dun, ninominate ko sya..... :D :D :D
@squatt3r,
eto yung gainclone building thread sa kabila, posted by efren, http://www.electronicslab.ph/forum/index.php?topic=29231.100
daig pa ang bot pag nagbantay hahaha :D :D :D
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parang pagiging mod lang yan, di ka pwede mag apply, you have to be picked. ;D
parang green lantern! ;D
what do you mean sir markcrenz? mahirap gawin yung kit ni mauro?
as master jojo said, if this is your first build, basic muna.
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makajoin nga dun sa kabila mukhang madami akong matututunan doon.
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makajoin nga dun sa kabila mukhang madami akong matututunan doon.
mga techies ang mga tao doon....you will have more to gain....
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kelangan ko pala ng session with Robert Boylestad.
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parang green lantern! ;D
as master jojo said, if this is your first build, basic muna.
green minded sir hahaha ;D
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kelangan ko pala ng session with Robert Boylestad.
sus kaya mo yan sir. what you need is an afternoon session with your chip's datasheet. I print it and instead of FHM or Playboy that's what I bring when I go to the restroom. ;D
seriously, don't overload your mind all at once with so many circuits, basic lang muna then go on from there kasi aside from the skills you also need to develop a set of big cojones to build more complex designs. ;)
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mga sir patulong naman po.
bumili ako kanina ng 24V 0 24V 6A na transformer and mga parts for LM3886TF gainclone
power supply pa lang di ko na mapagana :'( :'(
yung basic symmetric power supply na nga lang basis ko, meron paring nag susurge,
nung una umiinit lang yung mga diodes kaya tinatanggal ko kaagad, next try is may magic smoke na.
ano kaya cause nun?
eto po yung basis ko for power supply:
http://freecircuitdiagram.com/2008/08/28/basic-symmetric-power-supply/
yung mga diodes ko for rectifier is for 6A and up to 50V (6A05 MIC), yun yung binigay sakin sa deeco.
dun sa capacitor naman ginawa kong dalawa yung C2 and C4 10000uF 50V so bali apat na 10000uF.
normal po ba kapag tinest yung continuity ng power supply na may center tap is parang mag kakashort yung tatlo?
sakto naman po yung output nung transformer, chineck ko ang voltage AC niya without the circuit almost 25V, and pag both ends 50V AC naman.
ano po kayang problema? possible po ba na mali yung ginamit ko para sa rectifier diodes? and pwede ko pa ba gamitin yung mga diodes kahit uminit na? sa physical appearance ok na ok pa naman sya.
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check mo mabuti yung layout mo at orientation ng parts kung tugma nga sa diagram.
diodes should be rated at least twice the transformer current para may allowance sa startup surge. your 10mF caps require huge currents during initial charging.
transformer windings have very low resistance. mahabang wire lang yan na nakaikot sa loob.
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check mo mabuti yung layout mo at orientation ng parts kung tugma nga sa diagram.
diodes should be rated at least twice the transformer current para may allowance sa startup surge. your 10mF caps require huge currents during initial charging.
transformer windings have very low resistance. mahabang wire lang yan na nakaikot sa loob.
thank you sir,
so dapat palitan ko na sir yung diodes ko? tatlong beses ko na syang inulit ganun pa rin :(
ok lang ba yung doble ang current and doble rin ang voltage?
ang masama pa ayaw dumikit ng soldering lead sa kanya, kaya ang ginagawa ko pinapaikutan ko
muna ng wire bago ko isolder.
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thank you sir,
so dapat palitan ko na sir yung diodes ko? tatlong beses ko na syang inulit ganun pa rin :(
ok lang ba yung doble ang current and doble rin ang voltage?
ang masama pa ayaw dumikit ng soldering lead sa kanya, kaya ang ginagawa ko pinapaikutan ko
muna ng wire bago ko isolder.
get the robust square metal bridge diodes, 200v 35a yata. scrape mo muna paa ng diodes, baka nag-umido during storage. better hone your soldering skills na rin. may tips sa web re proper soldering techniques, google mo na lang.
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(http://freecircuitdiagram.com/wp-content/uploads/2008/08/basic_symmetric_power_supply.gif)
24-0-24, yung gitna ng traffo ang 0, yung 2 outer ang 24.....
yung 6A05 palitan mo ng 6A20 at least, rating of diode should at least be 3 x Vsec, or 3 x 48 ~ 150, diode must be rated for 200volts piv, peak inverse voltage...
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get the robust square metal bridge diodes, 200v 35a yata. scrape mo muna paa ng diodes, baka nag-umido during storage. better hone your soldering skills na rin. may tips sa web re proper soldering techniques, google mo na lang.
ok sir salamat po, pag may time mamaya baka makadaan po ako ng deeco
regarding sa pag solder nilagay ko kasi sa universal PCB e, kapag P2P technique po ba ilang gauge dapat
ng wire ang gagamitin?
another question sir, ok lang ba na isang supply lang sa 2 channel? and ok lang rin po ba kahit hindi na gumamit ng voltage regulator dun sa power supply?
by the way 250PHP lang sa deeco yung LM3886TF nila, nag tanong ako sa newport 350PHP. ;D
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24-0-24, yung gitna ng traffo ang 0, yung 2 outer ang 24.....
yung 6A05 palitan mo ng 6A20 at least, rating of diode should at least be 3 x Vsec, or 3 x 48 ~ 150, diode must be rated for 200volts piv, peak inverse voltage...
maraming salamat po sir, so mali po pala talaga yung ginamit kong diode?
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ok sir salamat po, pag may time mamaya baka makadaan po ako ng deeco
regarding sa pag solder nilagay ko kasi sa universal PCB e, kapag P2P technique po ba ilang gauge dapat
ng wire ang gagamitin?
awg #18 pwede na pero ingat ka sa sobra haba na wiring, keep it short.
another question sir, ok lang ba na isang supply lang sa 2 channel? and ok lang rin po ba kahit hindi na gumamit ng voltage regulator dun sa power supply?
ok lang, wag mo muna problemahin yun, patunugin mo muna. ;)
by the way 250PHP lang sa deeco yung LM3886TF nila, nag tanong ako sa newport 350PHP. ;D
nakakasiguro ka naman ba diyan sa Php250 mo na LM3886TF? :D :D :D
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awg #18 pwede na pero ingat ka sa sobra haba na wiring, keep it short.
ok lang, wag mo muna problemahin yun, patunugin mo muna. ;)
nakakasiguro ka naman ba diyan sa Php250 mo na LM3886TF? :D :D :D
ok sir maraming salamat po.. hehehe
pano pong nakakasiguro sa LM3886TF? meron po bang fake nito? :( dalawang beses ko pa tinanong yung
babae e kasi nagulat rin po ako na 250 lang.
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ok sir maraming salamat po.. hehehe
wag ka muna pasalamat sir, paandarin muna natin power supply mo hehehe... bili ka na nun sinabi ni Tony na diodes bilis... ;D
pano pong nakakasiguro sa LM3886TF? meron po bang fake nito? :( dalawang beses ko pa tinanong yung
babae e kasi nagulat rin po ako na 250 lang.
meron
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wag ka muna pasalamat sir, paandarin muna natin power supply mo hehehe... bili ka na nun sinabi ni Tony na diodes bilis... ;D
meron
PATAY :(
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lakasan mo ang loob mo, malay mo naka tiyempo ka naman ng mura...
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walang report na fake lm3886tf na aware ako....at least dun sa site ni rod elliot.....last time, 3yrs ago, nagtanong ako sa eleshop, nasa 350 yan, mura din sa newport di ko lang alam ang price....teka...330 sa newport: http://www.newportelec.com/ic_l.html
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LM4780 chips na agad para twice the power ng LM3886! ;D
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walang report na fake lm3886tf na aware ako....at least dun sa site ni rod elliot.....last time, 3yrs ago, nagtanong ako sa eleshop, nasa 350 yan, mura din sa newport di ko lang alam ang price....teka...330 sa newport: http://www.newportelec.com/ic_l.html
bumili ako sa newport ng LM3914, pareho umusok. kaya pala kayudin lang ng fingernails ko natatanggal na yun label. ganun din sa 3875, parang pintura lang yun label. yun 1875 nila laser printing, so far so good.
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diode nga po ang problema, bumili ako ng P60J kanina ayun gumana na..
ang kaso nung una +35V yung output ng positive and -35V naman ang negative,
after a while nung sinolder ko na mga connection, nagin +23V na lang yung positive,
pero -35V pa rin ang negative.. hayy ano na naman kay problema :(
malamang may capacitor na hindi naka-solder.
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malamang may capacitor na hindi naka-solder.
salamat sir! yun nga, yung nasa ground hehe. hirap pala nito :) pero enjoy :)
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salamat sir! yun nga, yung nasa ground hehe. hirap pala nito :) pero enjoy :)
huwag mo masyado isipin yun hirap, isipin mo may natutunan ka. ayusin mabuti ang hinang, baka nakadikit lang ng kanin yan. ;D
enjoy and good luck!
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magandang araw mga sir,
partly napatunog ko na po yung lm3886, kaso merong mga problema.
ang pinag basehan ko po ng diagram ay yung nilabas na schematic ng National Semiconductor.
link: http://diyaudioprojects.com/Chip/LM3886_CA/LM3886_CA.htm
may mga ibang values po akong ginamit kasi walang available dun sa nabilhan ko tulad ng
Rin = 50k 6leg potentiometer ginamit ko
Value ng capacitor, instead of 100uF 50V, 100uF 63V, and mylar lang po yung 0.1uF na ginamit ko
Rz = 2.2ohms 2W lang ginamit ko
base sa schematic sa link yun Cs (capacitor) po ba ay dapat mag parallel ako ng 100uF and 0.1uF?
eto po naging result noong pinatunog ko yun isang channel:
Iphone po yung ginamit kong audio source, noong triny ko na paganahin
nagbabago ang volume ng iphone, at tumitigil sa pag play ng kanta.
kapag mahina at walang vocals at malakas na bass yung kanta, ok naman yung pag play
kaso kapag may vocals na, nagbabago na yung volume ng iphone.
ano po kayang problema nito? maraming salamat po..
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eto po naging result noong pinatunog ko yun isang channel:
Iphone po yung ginamit kong audio source, noong triny ko na paganahin
nagbabago ang volume ng iphone, at tumitigil sa pag play ng kanta.
parang delikadong masira iphone mo dyan. yung amp input baka may voltage. dapat wala. check for possible shorts between pins. recheck mo amp circuit.
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parang delikadong masira iphone mo dyan. yung amp input baka may voltage. dapat wala. check for possible shorts between pins. recheck mo amp circuit.
+1, input offset currents yan...
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lagyan mo ng capacitor sa top ng volume control.......4.7ufd/50 volts....
(http://diyaudioprojects.com/Chip/LM3886_CA/F01-LM3886-chipamp.png)
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chineck ko sir yung input wala namang voltage 0V,
then yung pin 1 = 35V
pin 4 = 35V rin
nung nilagyan ko naman ng capacitor sa input, humina yung sound pero same problem pa rin..
:'(
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-35 dapat sa pin 4
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-35 dapat sa pin 4
sorry, -35V nga po sa pin 4..
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ok na mga sir, maraming salamat po sa mga tumulong..
kasalanan pala nung ginamit kong y cable (RCA to 3.5mm jack)
yung ginamit ko e yung may video, nung ginamitan ko ng red and white lang to 3.5mm
ayun solve ang problema hehehe..
malakas nga hehe, isang channel pa lang ginagamit ko, nasira ko kasi yung isang LM3886TF :'(
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we all learn from mistakes, kasama yan......
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we all learn from mistakes, kasama yan......
oo nga sir, pero worth it naman kapag napagana na ng maayos hehe..
maraming salamat po..
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patulong uli mga sir,
sa tuwing ikakabit ko yung 2nd channel ng LM3886 palaging pumuputok,
e parehong pareho naman ng orientation ng components yung ginawa ko,
yung isang channel ok naman.
ang ginawa ko sa power supply ini-split ko sa dalawa yung V+ V- GND.
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paki describe/drawing mo yun power supply mo para maintindihan namin at makita kung saan ang mali...
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this is my LM4702A board awaiting installation:
(http://i5.photobucket.com/albums/y155/leoman53/4702/IMG_1948.jpg)
(http://i5.photobucket.com/albums/y155/leoman53/4702/IMG_1944.jpg)
(http://i5.photobucket.com/albums/y155/leoman53/4702/IMG_1947.jpg)
(http://i5.photobucket.com/albums/y155/leoman53/4702/IMG_1946.jpg)
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Mga Sirs,
Napaandar ko na pala yung LM1875 stereo at maganda ang tunog. Thanks a lot sa inyo.
Ginawa ko rin yung LM3875 stereo din at mas lalong maganda ang tunog at first time lang ay tumunog
na agad sila kaya gumawa agad ako nang mga kaparis. Thanks a lot mga Sirs.
1.0 May tanong lang po ako. Kapansin pansin pala na yung left and right channel sa LM1875 at pareho din sa LM3875 ay malakas ang isa at mahina ang isa na channel. Ganito ba talaga ito? Separate ang PS ang ginawa ko. Ano palang magandang gawin dito para mag balance.
2.0 Pag power start at pag power off pala ay may sound na malakas (thog). Ano palang gawin ko para maalis ang malakas na sound.
Again mga Sirs, Thanks a lot.
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gumamit ka ba ng stereo potentiometer sir? dapat same vol lang yan since same resistor values naman gamit mo on both. If may vol pot i suggest bili ka magandang klase like alps. :)
check mo sir wiring layout, solder points at grounding. wala naman ako ne encounter na pop up noise sa gc ko pag power off. i'm using lm3875 also.
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vimikay, anong circuit yan? pwede ka gumamit ng speaker protector/time delay relay...
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Saan ba puwede maka bili ng LM 3875 kasi walang stocks sa Raon. Sa Alexan wala din stocks.thanks
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here is the LM3886T gc with 2 6N23P tubes as front end inside a Sakura AV3310 chassis
(http://i646.photobucket.com/albums/uu184/efrennoble/100_6893.jpg)
"oldskool" point to point wiring for the gc chips
(http://i646.photobucket.com/albums/uu184/efrennoble/100_6898.jpg)
modern approach for the tubes using PCB
(http://i646.photobucket.com/albums/uu184/efrennoble/100_7112.jpg)
(http://i646.photobucket.com/albums/uu184/efrennoble/100_7114.jpg)
regulator block for the chips' +/-33Vdc
(http://i646.photobucket.com/albums/uu184/efrennoble/100_6897.jpg)
now inside the mutilated Sakura
(http://i646.photobucket.com/albums/uu184/efrennoble/100_7143.jpg)
(http://i646.photobucket.com/albums/uu184/efrennoble/100_7152.jpg)
common mode choke for the tube's supply rails
(http://i646.photobucket.com/albums/uu184/efrennoble/100_7154.jpg)
the LM3886T gc chips & 6n23P tubes thru the kindness of sir TonyT.
the circuit design is from Joe Rasmussen's site, an inverted Thorsten-Loesch circuit.
(http://www.customanalogue.com/images/series_application-2.gif)
unfinished as of the moment, still working on the makeover of the front panel :D
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Another chipamp in the making. I created my own PCB layout, the schematic is based on Mauro Penasa's design which is highly regarded in DIYAudio. I uploaded the layout files here (http://www.diyaudio.com/forums/chip-amps/238212-mini-my-ref-rev-c-4.html#post3577432) just in case you want to build one. :)
(http://i28.photobucket.com/albums/c247/jlester87/DIY%20Audio/lm3886.png)
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my LM1875 gainclone
(http://sphotos-b.ak.fbcdn.net/hphotos-ak-prn1/1072393_10151813845301563_14179138_o.jpg)
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my LM1875 gainclone
(http://sphotos-b.ak.fbcdn.net/hphotos-ak-prn1/1072393_10151813845301563_14179138_o.jpg)
Hmmm, how's the sounds bro?
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Hmmm, how's the sounds bro?
hehehe tambay muna kt88 ko bro,swak na swak sa proac 1sc clone ko.ang masaya dito pwede i tweak to your liking,pwede taasan ang gain kung ang source mo ay yung mga ipod/pmp lang pwede din lagyan ng volume pots para kahit wala na preamp at higit sa lahat ehh hindi masakit sa bulsa hehehe
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Wow buo na sir? Magkano inabot po?
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how much po ba ang budget for a gain clone amp?:)
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the power traffo will set you back about 1000, the chips at 350(you can ask for free samples from TI), caps and parts another 500 or so...but the caveat here is that you do it yourself.....
btw, this thread is 10 years old......:D
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the power traffo will set you back about 1000, the chips at 350(you can ask for free samples from TI), caps and parts another 500 or so...but the caveat here is that you do it yourself.....
btw, this thread is 10 years old......:D
that's where the fun begins sir Tony,natuwa ako na yung unang diy project ko tumunog on my first try at walang umusok or something hehehe,pero i follow every safety steps na nirerecommend ng mga taga diyaudio like checking dc offset before connecting the speaker and checking the voltage etc etc.
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dc offset should not be more than +-100mV, otherwise yung speakers mo sobrang offset din mechanically...
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don't forget the speaker protect.. mahirap na baka matusta ang speaker if anything happens to your amp
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don't forget the speaker protect.. mahirap na baka matusta ang speaker if anything happens to your amp
I put zobel network, pero lagyan ko pa din ng separate speaker protection para panigurado talaga.
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anyone from commonwealth who can let me audition a gainclone? am really interested to hear the sound of this amp:)
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Maybe anyone who has JojoD's BabyG or 75watt or 150watt/channel JDLabs gainclone, please help fishda get a taste of the gainclone.
Btw fishda whats your speaker and its specification?
anyone from commonwealth who can let me audition a gainclone? am really interested to hear the sound of this amp:)
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not sure sir joey of the specs but it's a proac clone by sir anthony:)
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What amp are you using now?
not sure sir joey of the specs but it's a proac clone by sir anthony:)
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anyone from commonwealth who can let me audition a gainclone? am really interested to hear the sound of this amp:)
Meron ako, class D, hindi gainclone.
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anyone from commonwealth who can let me audition a gainclone? am really interested to hear the sound of this amp:)
Tandang sora QC ako pero baka next month ko pa matapos gainclone ko eh..
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same here. i live near tandang sora. just advise me sir when you get to complete your build.
my purpose btw is to get the best bang for the buck amp for music listening. i want something that sounds good but doesn't consume too much electricity because i'd like to listen to music a lot. i listen to lots of jazz and classical music.
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Meron ako, class D, hindi gainclone.
any amp will do sir. i'm sure if it's from you it must sound good:)
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any amp will do sir. i'm sure if it's from you it must sound good:)
Not really sir. Kanya kanyang preference.
Sounds like a plan to me this month! What's your speaker?
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It will really depend on which amp can drive your speaker properly so that it will sound good. Class D or gainclone may be cheaper but the question is if it will be able to drive or match your speaker.
same here. i live near tandang sora. just advise me sir when you get to complete your build.
my purpose btw is to get the best bang for the buck amp for music listening. i want something that sounds good but doesn't consume too much electricity because i'd like to listen to music a lot. i listen to lots of jazz and classical music.
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not sure sir joey of the specs but it's a proac clone by sir anthony:)
ahhh this was my first/old set up. Proac Clone + Jojo's BabyG. Mas madali pa idrive yung Dynes 42 kesa sa Proac Clone. :(
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those proac clones have very low sensitivity, you'll need at least a 50 watter to make them sing at moderate levels. a stereo lm3886 with 25-0-25 vac transformer would be a good amp for those speakers.
but if your objective is not to consume too much electricity, better get klipsh or other high sensitivity speakers. more sound at less power.
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i did think too that these are hard to drive. my fisher ca860 makes them sound just fine. i guess i'd have to wait for my luxman m02 from sir rene. would an lm3886 be an expensive amp?
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^more than 2k only, plus an indefinite amount for the casing, depending on your taste and budget. the cheapest i think is 550 from deeco, while around 3k up for "audiophile casings" (note the qoutes, looks have nothing to do with sound quality).
the power traffo will set you back about 1000, the chips at 350(you can ask for free samples from TI), caps and parts another 500 or so...but the caveat here is that you do it yourself.....
btw, this thread is 10 years old......:D