Author Topic: Newbie & Not-so Noob Thread: Questions (FAQ) on Receivers/Amplifiers (Read 192559 times)

joan2 · « **Reply #150 on:** Nov 03, 2003 at 12:49 PM »

Quote from: Leiko on Nov 03, 2003 at 08:23 AM

thank you Joan...

well, there's no shortcut to auto-volt. A swtiched/multi-tap will be economical indeed.

followup question: is there a way to protect a 110v component by adding a fuse (or something) that will break in case it's plugged accidentally to 220V?

yes, i posted that in akyat's thread about surplus amps, when akyat comes to my place, we will take pictures and post the schematics, a cheap tweak that can save you a lot in repair costs...

joan2 · « **Reply #151 on:** Nov 03, 2003 at 12:57 PM »

Quote from: akyatbundok on Nov 03, 2003 at 10:21 AM

About the speaker A & B terminals of an amp: Aren't they just connected in parallel?

I was wondering if this can be used to compare speaker cables. I'll plug cable A into speaker A, and cable B into speaker B. Then both will connect to one speaker pair with the HF/LF jumper in place. So when i switch to speaker A, i will be listening to cable A... when i switch to speaker B, i will be listening to cable B.

Now if i switched on both A & B with the jumper in the speakers still in place, will it short my amp? Note that the + and - aren't touching, just A+ to B+, and A- to B-. Well actually i know the answer to this one coz curiosity got the better of me and i couldnt resist. Not the most scientific procedure that, risking a short like i did, but in case people out there are starting to get those bright ideas, at least the gurus here could warn them.

i do not see any problem here, provided you follow the polarity, normally the black terminals are all at ground potential, a quick continuity check with a dmm should confirm this! so it is the red terminals that are selected when you choose between A or B, both when you select A+B...indeed this could be a quick way to a switch between speaker cables, or audition 2 speakers in one session...

Leiko · « **Reply #152 on:** Nov 04, 2003 at 07:42 AM »

Quote from: joan2 on Nov 03, 2003 at 12:49 PM

yes, i posted that in akyat's thread about surplus amps, when akyat comes to my place, we will take pictures and post the schematics, a cheap tweak that can save you a lot in repair costs...

that will be very helpful. find this very practical.

thanks!

akyatbundok · « **Reply #153 on:** Nov 05, 2003 at 02:47 PM »

are power transistors just like power tubes -- when you change them, you change the sound of the amp?

or is it that the sound of an amp is made up of all its parts, so changing a power capacitor or the transformer will also change its sound? if so, which parts will have the most effect on the sound when changed?

ArnieSwarzie · « **Reply #154 on:** Nov 05, 2003 at 03:50 PM »

Quote from: MAYOR on Oct 17, 2003 at 10:10 PM

which of the three gives the best superb sound? pls enlighten me, tnx

There are 2 school of thought in comparison:
- the objective point of view
- the subjective point of view

The Objective point of way is to make parametric measurement of the performance of each amplifiers. The best of breeds of both type of amplifiers (tube and SS) yielded that SS always won hands down.

In some actual listening where both types have been tweaked to be of same loudness, the differences were hardly determined, especially if both amplifiers worked with less than few percent distortions.

The subjective point of view is where the word "superb" may rightly fall. "superb to whom"? Thus, the preferences of a person to the sound balance he likes determines superb condition. And there is no standard here, and also there is no point arguing which is superb and which is not. Part of the consideration here is the fact that our hearing deteriorates as we age. So different age groups may have different tonal inclinations.

With digital age, such subjectivity is more of a goner because the distortion or alteration to the sound can now be done in digital domain - very clean - and with various equalization in digital domain, sound of whatever you want can be tailor fitted to any amplifier. Its interesting to note that generic DVDs have built-in equalizer tool being applied in digital domain - and will be decoded by any AVR equipped with DACs.

Some people still go with tubes because it has vintage values (aesthetics), some still wanted soft clipping, and some wanted its tonal balance (distortions). To them, these are "superb"-ness. To others, these things may not be the case.

joan2 · « **Reply #155 on:** Nov 05, 2003 at 09:13 PM »

Quote from: akyatbundok on Nov 05, 2003 at 02:47 PM

are power transistors just like power tubes -- when you change them, you change the sound of the amp?

or is it that the sound of an amp is made up of all its parts, so changing a power capacitor or the transformer will also change its sound? if so, which parts will have the most effect on the sound when changed?

akyat,
changing parts on a ss amps will have an impact of sorts, but not quite the same as with tubes...some say changing output transistors changes the sound, this may be true, i have read in other forums, but ime, i barely notice....but there are good reasons to replace output transistors, for example, there are japanese transistors like the 2sa1302a/sc3281a that are superior to american transistors, and the reason for this is that the japanese transistor has better hFE linearity,and higher fT's. changing transformers to bigger va cap has an impact of power delivery as the higher rated ones will not sag in output as a lower rated one, changing electrolytic caps in the signal path to say polypropylene types have an impact, due to the fact that they will have much lower esr, and da(dielectric absorption)..than an electrolytic cap...

joan2 · « **Reply #156 on:** Nov 05, 2003 at 09:18 PM »

Quote from: ArnieSwarzie on Nov 05, 2003 at 03:50 PM

There are 2 school of thought in comparison:
- the objective point of view
- the subjective point of view

The Objective point of way is to make parametric measurement of the performance of each amplifiers. The best of breeds of both type of amplifiers (tube and SS) yielded that SS always won hands down.

In some actual listening where both types have been tweaked to be of same loudness, the differences were hardly determined, especially if both amplifiers worked with less than few percent distortions.

The subjective point of view is where the word "superb" may rightly fall. "superb to whom"? Thus, the preferences of a person to the sound balance he likes determines superb condition. And there is no standard here, and also there is no point arguing which is superb and which is not. Part of the consideration here is the fact that our hearing deteriorates as we age. So different age groups may have different tonal inclinations.

With digital age, such subjectivity is more of a goner because the distortion or alteration to the sound can now be done in digital domain - very clean - and with various equalization in digital domain, sound of whatever you want can be tailor fitted to any amplifier. Its interesting to note that generic DVDs have built-in equalizer tool being applied in digital domain - and will be decoded by any AVR equipped with DACs.

Some people still go with tubes because it has vintage values (aesthetics), some still wanted soft clipping, and some wanted its tonal balance (distortions). To them, these are "superb"-ness. To others, these things may not be the case.

this is a fair comment, i guess dissagreements happens when some people claim tubes being superior to ss and vice-versa...sufice to say that tubes are sweet sounding and that ss amps packs a wallop!!!!

going back to ss amps, not all ss amps that measure well in terms of thd and im's guarantees it will get good reviews on actual listening tests!!

av_phile · « **Reply #157 on:** Nov 06, 2003 at 03:34 PM »

Quote from: joan2 on Nov 05, 2003 at 09:18 PM

going back to ss amps, not all ss amps that measure well in terms of thd and im's guarantees it will get good reviews on actual listening tests!!

I read somewhere it won't get reviewed at all if the manufacturer doesn't give advertising $$$ to the magazine.

joan2 · « **Reply #158 on:** Nov 06, 2003 at 07:54 PM »

av_phile,
not only that, manufacturers came up with this numbers game, lowest thd, im, very high damping factor, very high slew rates etc.,etc., etc,. all aimed at getting consumers buy their products, but consumers can not understand all this technical mambo jambo being floated about, so what are the consumers to do? audition the products before they buy, do not listen to someone else's say so...but trust their ears alone!!! if they like what they hear, then go ahead and buy....

av_phile · « **Reply #159 on:** Nov 06, 2003 at 08:53 PM »

Joan2,

To a certain extent, yes, do buy what your ears like .I also find myself enjoying listening to directly heated single ended valve amplifiers. I don't buy them, not because they are expensive, but because I know the reason why tube sounds are pleasant. It is because of even-ordered harmonic distortions that at generous servings of 0.5% to 3% do give the sound a lot of pleasing body and presence that IS NOT SUPPOSED TO BE THERE coming out of the speakers.

Those numbers, done properly from an honest intention, is a good inidcation of performance. There is a history behind those numbers that were arrived at by consensus from audio engineers and audiophiles and are meant to allow objective evalution and comparison of these equipment, Measuring instruments can't mask, hide details or lie. But the ears and the mind can. Admittedly, the marketing guys can distort those figures to what the consumers want to hear and buy.

They won't tell everything, ofcourse. The ears are the final judge (and the wife the executioner,

). But they're a good start. I certainly wouldn't waste my time to even consider auditoning an amp specified with 1% THD at rated power like one Pioneer HT receiver I've seen. Or an amp whose power rating is measured at 1Kz only or worst, in PMPO. Or whose specs are silent about IM and Slew rates and Rise times, interchannel crosstalk, noise floors and dynamic ranges, etc. I will only auditioni if i find the specs honest and complete and up to my liking or standards.

Rather than ignore them, maybe it'sa good idea to educate consumers about them, so they don't get duped by savy marketers of lousy products. Then again, maybe not knowing about these number is just fine so savy marketers can't use those numbers to dupe consumers. In my case, I am just too old in the hobby not to know.

levi · « **Reply #160 on:** Nov 07, 2003 at 02:11 AM »

Quote from: ArnieSwarzie on Nov 05, 2003 at 03:50 PM

There are 2 school of thought in comparison:
- the objective point of view
- the subjective point of view

The Objective point of way is to make parametric measurement of the performance of each amplifiers. The best of breeds of both type of amplifiers (tube and SS) yielded that SS always won hands down.

In some actual listening where both types have been tweaked to be of same loudness, the differences were hardly determined, especially if both amplifiers worked with less than few percent distortions.

The subjective point of view is where the word "superb" may rightly fall. "superb to whom"? Thus, the preferences of a person to the sound balance he likes determines superb condition. And there is no standard here, and also there is no point arguing which is superb and which is not. Part of the consideration here is the fact that our hearing deteriorates as we age. So different age groups may have different tonal inclinations.

With digital age, such subjectivity is more of a goner because the distortion or alteration to the sound can now be done in digital domain - very clean - and with various equalization in digital domain, sound of whatever you want can be tailor fitted to any amplifier. Its interesting to note that generic DVDs have built-in equalizer tool being applied in digital domain - and will be decoded by any AVR equipped with DACs.

Some people still go with tubes because it has vintage values (aesthetics), some still wanted soft clipping, and some wanted its tonal balance (distortions). To them, these are "superb"-ness. To others, these things may not be the case.

Are you saying that the tube users are enjoying distortions? So if you distort a SS it will sound like tubes?

joan2 · « **Reply #161 on:** Nov 07, 2003 at 06:40 AM »

Quote

Are you saying that the tube users are enjoying distortions? So if you distort a SS it will sound like tubes?

you will be surprised, they introduce distortions into ss amps to make it sound like tubes!!! but this is for musicians who insist that tubes sound better for musical instruments!!! nothing to do with home music reproduction, but who knows mybe in the future somebody may come up with such a circuit...as for me i wouldn't bother!!! if i am not mistaken, distortion levels better than 0.25% can no longer be heard!!so what good is a thd level of 0.001!!!manufacturers use this to get premium price on their amps....
this should tickle your imagination!!!http://www.diyaudio.com/forums/showthread.php?s=&threadid=20045 or this one:http://www.diyaudio.com/forums/showthread.php?threadid=4298&perpage=15&pagenumber=1

Quote

Rather than ignore them, maybe it'sa good idea to educate consumers about them, so they don't get duped by savy marketers of lousy products. Then again, maybe not knowing about these number is just fine so savy marketers can't use those numbers to dupe consumers. In my case, I am just too old in the hobby not to know.

amen, to this, consumers are duped either way....

av_phile · « **Reply #162 on:** Nov 07, 2003 at 09:17 AM »

Quote from: levi on Nov 07, 2003 at 02:11 AM

Are you saying that the tube users are enjoying distortions? So if you distort a SS it will sound like tubes?

Even-order harmonic distortions are pleasant to the ears, imparting richness, body and even presence to the signals. That's the province of valve amplification that makes the sonics warmer. The more, the merrier, but ofcourse up to a certain limit.

In contrast solid state amplification introduces odd-order harmonic distortions that are grating and harsh. Thus, increasing inherent ss distorition will never make them sound like tubes. But i read somewhere that artificially introducing even-ordered harmonic distortions into SS amps makes them sound like tubes. I heard Carver do this in their SS amps, in addition to soft clipping.

Nice thing about ss amps is the progress over the last 30 years with which designers have brought thiose harsh odd harmonic distortions to minute 0.01% to 0.001% levels at full rated power that it makes them academic at any volume levels below clipping. Can't say the same for tube amps whose even ordered distortion figures are actually desireable as they impart their signature sonic warmth. And not much is done to remove them.

But as I said in my previous post, i also like valve sounds. The sound is different. Whether superior to ss, I leave that to the beholder. In my own view, any form of harmonics that are not there with the source signals re-shapes that signal and is not my piece of cake. Whether they sound pleasant or not, i just can't enjoy the music knowing at the back of my head that something is being added to the sonics that is not supposed to be there.

There is this school of thought that says all amplifciation result in the same signals getting bigger waveforms and theoreticaly should sound identical. It is when that amplifcation reaches distortion levels that sonic differences between devices begin to reach our ears. That's because distortion is a form of sonic coloration

levi · « **Reply #163 on:** Nov 07, 2003 at 09:55 AM »

hmmmm

Leiko · « **Reply #164 on:** Nov 07, 2003 at 09:56 AM »

Quote from: av_phile on Nov 07, 2003 at 09:17 AM

In my own view, any form of harmonics that are not there with the source signals re-shapes that signal and is not my piece of cake. Whether they sound pleasant or not, i just can't enjoy the music knowing at the back of my head that something is being added to the sonics that is not supposed to be there.

AMEN, AMEN, AMEN...

. Nothing more, nothing less. Just right -- isn't that Fidelity all about?

levi · « **Reply #165 on:** Nov 07, 2003 at 10:06 AM »

same reasoning with jofverski. Same school?

av_phile · « **Reply #166 on:** Nov 07, 2003 at 10:21 AM »

Quote from: levi on Nov 07, 2003 at 10:06 AM

same reasoning with jofverski. Same school?

If he's from UP. But really now, do i sound the same?

av_phile · « **Reply #167 on:** Nov 07, 2003 at 10:25 AM »

Quote from: Leiko on Nov 07, 2003 at 09:56 AM

AMEN, AMEN, AMEN... . Nothing more, nothing less. Just right -- isn't that Fidelity all about?

Yup, you got it. That's Hi-Fi. Though i recently found out some members don't consider Hi-Fi a criteria for muscial enjoyment. Well, whatever makes us happy, right?

akyatbundok · « **Reply #168 on:** Nov 07, 2003 at 12:12 PM »

interesting topic... found this link about a guy who says his combination of FET and bipolar transistor devices has the same curve as a triode tube.

--> The Solid State Tube

--> The Solid State Tube Preamp

joan2 · « **Reply #169 on:** Nov 07, 2003 at 12:22 PM »

Quote from: akyatbundok on Nov 07, 2003 at 12:12 PM

interesting topic... found this link about a guy who says his combination of FET and bipolar transistor devices has the same curve as a triode tube.

--> The Solid State Tube

--> The Solid State Tube Preamp

akyat,
this is the third technology, first is the bjt, second are fet's and mosfet's, then this one, igbt's...this last one is nothing more than a combination of the two, it combines the very high input resistance of mosfets and the very low output resistance of bjt's..this device was invented for motor driving purposes and eventually found its way into audio....i haven't even touched this device yet.....
going back to my favorite encyclopedia:
http://www.diyaudio.com/forums/showthread.php?s=&threadid=2131&highlight=
http://www.diyaudio.com/forums/showthread.php?s=&threadid=2131&highlight=
as before, new technology is always met with so much enthusiasm, whether it can live up to expectations is another thing, me i'd stick it out with my leach amps....

joan2 · « **Reply #170 on:** Nov 07, 2003 at 12:38 PM »

Quote from: av_phile on Nov 07, 2003 at 10:21 AM

If he's from UP. But really now, do i sound the same?

he's passionate, you are full of compassion!!!

av_phile · « **Reply #171 on:** Nov 07, 2003 at 01:18 PM »

Quote from: joan2 on Nov 07, 2003 at 12:38 PM

he's passionate, you are full of compassion!!!

Ganun ba? I lkke that.

akyatbundok · « **Reply #172 on:** Nov 07, 2003 at 03:34 PM »

is it possible to get the best of both worlds? - a high power, low cost solid state amp that degrades gracefully like tubes. i don't really understand Gabe Velez's explanation behind his circuitry, but i do understand the claim he is making. well, the title says it all: the solid state tube. i'm just curious if anybody has verified it yet or whether it has any merit technically.

av_phile · « **Reply #173 on:** Nov 07, 2003 at 04:01 PM »

Quote from: akyatbundok on Nov 07, 2003 at 03:34 PM

is it possible to get the best of both worlds? - a high power, low cost solid state amp that degrades gracefully like tubes. i don't really understand Gabe Velez's explanation behind his circuitry, but i do understand the claim he is making. well, the title says it all: the solid state tube. i'm just curious if anybody has verified it yet or whether it has any merit technically.

Right now I am aware only of very expensive amps that are able to deliver the good trraits of tubes and ss. There are Carver, Mark Levinson and McIntosh amps to name the most prominent ones. NAD is able to deliver the soft clipping features of tubes but at moderate power. None of them fall into low-cost category. I think even DIY amps with such a spec will not either. But I am confident evolving technology and mass prodction engineering will find a way to make these things possible - getting the best of both worlds - at prices consumers can afford. I just hope I am still alive and able to hear when it finally does.

akyatbundok · « **Reply #174 on:** Nov 07, 2003 at 04:24 PM »

hi sirs, did i get it correctly, that the main difference between tubes & ss are in the way they handle clipping? tubes just have more finesse when pushed to its limit. if so, then the trick is to make the ss amp so high-powered that it will never clip? but the argument from the tube camp is that all amps will clip anyway because the musical peaks will require 1000w or more to reproduce without distortion.

av_phile · « **Reply #175 on:** Nov 07, 2003 at 04:54 PM »

Quote from: akyatbundok on Nov 07, 2003 at 04:24 PM

hi sirs, did i get it correctly, that the main difference between tubes & ss are in the way they handle clipping? tubes just have more finesse when pushed to its limit. if so, then the trick is to make the ss amp so high-powered that it will never clip? but the argument from the tube camp is that all amps will clip anyway because the musical peaks will require 1000w or more to reproduce without distortion.

There are more differences such as slew rates, rise times, THDs, noise floor, frequency response, microphonics, etc.

But what you are suggesting is in fact being done - allow more power bandwidth so that the onset of clipping beccomes unnecessary at listening levels. Many audiophiles actually shy away from modestly powered SS amps which is basically the province of entry level stuff and go for those that give at least 250 watts RMS per channel with instantaneous current handling capability reaching as far as twice that. Clipping is almost never reached at half volume or more for either continuous and peak signals. So get the most powerful SS amps you can buy and enjoy!!!

joan2 · « **Reply #176 on:** Nov 07, 2003 at 05:33 PM »

Quote from: akyatbundok on Nov 07, 2003 at 03:34 PM

is it possible to get the best of both worlds? - a high power, low cost solid state amp that degrades gracefully like tubes. i don't really understand Gabe Velez's explanation behind his circuitry, but i do understand the claim he is making. well, the title says it all: the solid state tube. i'm just curious if anybody has verified it yet or whether it has any merit technically.

ss class A amps can give tubes a good run!!! with ss amps, the rule is not to play it real hard so it does not clip, most of the listening will be done in the 250mW to 2watt or so range anyway, so an amp rated for 250watt continous ave, will have plenty of headroom!!! a good ss state amp in my book will have the following specs:
1. an open loop bandwith of 20hz to 20khz.
2. a gain bandwith product of at least 8mhz.
3. has every stage with local degenaration.
4. all stages operates class A except the output transistors
5. uses cascoding in the vas stage.
6. is push-pull from input to out put
7. a thd of less than 0.2%
8. low overall negative feedback!!!

this thread about a classic classA amp should be a good read:http://www.diyaudio.com/forums/showthread.php?s=&threadid=11281 or this:http://www.diyaudio.com/forums/showthread.php?s=&threadid=3075

joan2 · « **Reply #177 on:** Nov 07, 2003 at 05:42 PM »

Quote from: akyatbundok on Nov 07, 2003 at 04:24 PM

hi sirs, did i get it correctly, that the main difference between tubes & ss are in the way they handle clipping? tubes just have more finesse when pushed to its limit. if so, then the trick is to make the ss amp so high-powered that it will never clip? but the argument from the tube camp is that all amps will clip anyway because the musical peaks will require 1000w or more to reproduce without distortion.

the one thing tube amps have is the output transformer which ss amps do not use...ss amps are always almost direct coupled, save some early designs that used output coupling capacitors, specially those that operate out of a single supply, direct coupled amps uses split rails...now going back to the transofrmer, when the tube overlaoads, the transformer is there to prevent dc from reaching the speakers as it can only couple ac's, in the case of the ss amp, there is nothing!

audiovoodo · « **Reply #178 on:** Nov 07, 2003 at 09:05 PM »

Quote from: joan2 on Nov 07, 2003 at 05:33 PM

ss class A amps can give tubes a good run!!! with ss amps, the rule is not to play it real hard so it does not clip, most of the listening will be done in the 250mW to 2watt or so range anyway, so an amp rated for 250watt continous ave, will have plenty of headroom!!! a good ss state amp in my book will have the following specs:
4. all stages operates class A except the output transistors
5. uses cascoding in the vas stage.
6. is push-pull from input to out put

If you want to make a solid state amp sound like vacuum tube...then just use tubes.

Can you have push-pull all the way? Don't you have a basic single ended input, then a splitter, then driver then the output...which is only the push-pull? Or the PASS amps that are single ended all the way.

Good SS amps, have the output stage in partial Class A...that is why the A/B class. You want all in class a except the output....

That will be a bad amp because of the transistor switching on and off....noise...at very low wattage...that would be very audible....or do want a digital amp.

What do you think of transformers? Colored?

levi · « **Reply #179 on:** Nov 07, 2003 at 11:31 PM »

Anyway what Solid State amps are you talking about? Does it include the common receivers like Pioneer,Marantz, Denon, Onkyo, Yamaha or Harman Kardon? My receiver is a solid state and very good sounding but its a far cry compared to my ordinary vintage tube? I dont think that Im just appreciating distortions because I have been using solid state ever since and I know what is good and bad. I did not try tubes if I was not impress with the sound. Im not referring to the high end solid state but Im just comparing a vintage amp to an average receiver. Aside from all the technical explanation which doesnt prove anything that it would translate to a good sound, why is it different? Listening and enjoying is different than reading and be fascinated by the specs. Guys any experience owning and listening to a tube amp for a long time?