Author Topic: gainclones diy anyone? (Read 383147 times)

joan2 · « **Reply #120 on:** Oct 15, 2003 at 12:22 PM »

garp,
yes, mylar will do, bit if you can find polystyrene types, that will be better....

Leiko · « **Reply #121 on:** Oct 15, 2003 at 09:46 PM »

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

)

well, i know, i have to get my feet wet first....

Garp · « **Reply #122 on:** Oct 16, 2003 at 04:03 PM »

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/. He offers both a tube and non-tubed version of the gainclone. What's common for both is the use of the LPF.

moonshow · « **Reply #123 on:** Oct 16, 2003 at 04:56 PM »

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.

Garp · « **Reply #124 on:** Oct 16, 2003 at 08:21 PM »

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.

Mika · « **Reply #125 on:** Oct 16, 2003 at 09:18 PM »

joan2, sent u pm

joan2 · « **Reply #126 on:** Oct 17, 2003 at 08:39 PM »

Quote from: Garp on Oct 16, 2003 at 04:03 PM

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/. 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!!!

kinyo · « **Reply #127 on:** Oct 18, 2003 at 12:56 AM »

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

joan2 · « **Reply #128 on:** Oct 18, 2003 at 07:18 AM »

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

moonshow · « **Reply #129 on:** Oct 18, 2003 at 12:44 PM »

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

kinyo · « **Reply #130 on:** Oct 18, 2003 at 08:31 PM »

thank you sir joan2

hyperaudio · « **Reply #131 on:** Oct 18, 2003 at 09:12 PM »

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!

Leiko · « **Reply #132 on:** Oct 18, 2003 at 11:35 PM »

Quote from: joan2 on Oct 17, 2003 at 08:39 PM

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....

JojoD818 · « **Reply #133 on:** Oct 19, 2003 at 04:15 AM »

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

joan2 · « **Reply #134 on:** Oct 19, 2003 at 07:17 AM »

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

this sub-amp idea may appeal to you:http://www.diyaudio.com/forums/showthread.php?s=&threadid=18859

kinyo · « **Reply #135 on:** Oct 20, 2003 at 12:47 AM »

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

joan2 · « **Reply #136 on:** Oct 20, 2003 at 07:11 AM »

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.....

joan2 · « **Reply #137 on:** Oct 20, 2003 at 07:15 AM »

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

i already ordered mine, although limit is 2-3 pcs of each kind....

joan2 · « **Reply #138 on:** Oct 20, 2003 at 01:30 PM »

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....

GC · « **Reply #139 on:** Oct 20, 2003 at 03:01 PM »

Speaking of powered subwoofers, how about class-D chips for subwoofers?
LM4651 and LM4652 is a 170W class-D solution.

joan2 · « **Reply #140 on:** Oct 20, 2003 at 03:58 PM »

gc,
medyo complicated, unless we can have access to pcb manufacturer willing to do short runs, expensive proposition yan....

JojoD818 · « **Reply #141 on:** Oct 20, 2003 at 05:07 PM »

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

homer · « **Reply #142 on:** Oct 20, 2003 at 11:36 PM »

jojo,

photo method b un? how about solder resist? how much for a stereo gc?

JojoD818 · « **Reply #143 on:** Oct 21, 2003 at 10:51 AM »

Hi homer,

I can only do single layer, no solder resist, no stencil. The pcb is drilled and covered with anti-oxidant coating.

JojoD

joan2 · « **Reply #144 on:** Oct 21, 2003 at 12:15 PM »

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

JojoD818 · « **Reply #145 on:** Oct 21, 2003 at 06:31 PM »

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

. 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.

JojoD

joan2 · « **Reply #146 on:** Oct 21, 2003 at 07:57 PM »

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....

JojoD818 · « **Reply #147 on:** Oct 21, 2003 at 09:44 PM »

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

joan2 · « **Reply #148 on:** Oct 22, 2003 at 07:34 AM »

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!!!

JojoD818 · « **Reply #149 on:** Oct 22, 2003 at 12:56 PM »

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!

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.

More power (to all of us),
JojoD