Why Tube Amps Sound Different (and better) Than SS Amps

[esldude]

Dear elsdude,

Just read your definition of an Audiophile.

How about this.

Someone who enjoys listening to and emotionally connecting with the music.

Fear?

Nah. Sounds like the mantra of a certain political party. Or the basis for many religions.

GG

You almost have it right there. Between science and superstition sounds about right for the audiophile world to me. Between the pit of a man's fears and the summit of his knowledge does as well. Plenty known about audio and the physics involved. Seems much of audiophillia is afraid they are missing out on something and find that something. And spend money on it in often chaotic fashion in what is half the time something real and half the time superstition about possible bad things no one can actually find. So pretty close to religion in my estimation.

The statement is a minor twist on Rod Serling's introduction to the Twilight Zone of course. And some of the odder parts of high end audio sure seem to fit in the Twilight Zone to me. We have phantom like worries no one can measure, and fanatical insistence such things are important. Those fears can only be allayed by hair shirted expensive incantations of just the right stuff by guru like figures.

 

[esldude]

The null test is a very useful development test but IMHO is of no help for the OP subject under debate in this thread. Most of the time we are not able to correlate direct measurements with with sound quality in a straightforward way, except for a few very basic properties that can not by any means explain our preferences. Should we dream that just measuring the residuals of a null test will explain how the amplifier sounds?

The question is why do SS and tube amps sound different. And you think a 'difference' test is of no help on the question? Do you see the humor here?

A null or difference test will show exactly what is different. The interpretation will take a bit of doing, but all the difference will be in that residual signal. By differencing a few types of signals one will know FR changes, distortion changes, ringing on xfmr's if there are any, microphonic feedback if any. etc. etc. I imagine a number of conjectured causes for the sound differences would turn out to be non-important, and perhaps some non-expected obvious differences would turn up to. I don't know what better signal to evaluate in hard terms how these two devices differ.

Carver, who is on record as having done such a thing to audible perfection or near it, found output impedance and FR the be the main thing behind the sound. Output impedance changes FR with speakers in audible ways, and according to Carver caused back EMF from the speaker to get send back through the amp again. Hanging a resistor on the output of a high feedback SS amp wouldn't get all the effect. The final piece of the puzzle that got the deep enough null for Carver was reducing power output of his amp in the lower frequencies. The CJ has less power there and it caused a sound difference with those speakers in use at least. So if he is telling most of the story, the important aspects are FR with drooping power bandwidth at frequency extremes due to the use of a transformer, output impedance causing further FR differences, and the effect of that recirculation of the signal by that output impedance.

I also agree with tomelex about interpreting said results. There is an abundance of useful and thoroughly researched psycho-acoustic knowledge about how our hearing works. It isn't complete, but it is far from trivial. And in audiophile land it is ignored and we hear how we don't know anything about how our brain processes what our ears hear. Some answers are available and ignored. Here this is how your hearing works. No, no that is not it, we don't know, I am looking for how our hearing works. Really is laughable. I also agree how people argue over things easily demonstrated like at Ethan's site. And you demonstrate it and there is some vague unsubstantiated idea that we hear far better on more complex material so this simple example does not apply.

 

[microstrip]

(...) Between science and superstition sounds about right for the audiophile world to me. (...)

Esldude,

Unless you are one of these persons that considers that when we refer to magic in audiophile debates we are referring to the supernatural, I fail to see why audiophiles are between "science and superstition". Do you knock the wood every time your Aura emits a crackling sound?

BTW, I would suppose that someone would use his signature to say something about himself, not about the others . Just my opinion, YMMV.

 

[microstrip]

The question is why do SS and tube amps sound different. And you think a 'difference' test is of no help on the question? Do you see the humor here?

A null or difference test will show exactly what is different. The interpretation will take a bit of doing, but all the difference will be in that residual signal. By differencing a few types of signals one will know FR changes, distortion changes, ringing on xfmr's if there are any, microphonic feedback if any. etc. etc. I imagine a number of conjectured causes for the sound differences would turn out to be non-important, and perhaps some non-expected obvious differences would turn up to. I don't know what better signal to evaluate in hard terms how these two devices differ.

Carver, who is on record as having done such a thing to audible perfection or near it, found output impedance and FR the be the main thing behind the sound. Output impedance changes FR with speakers in audible ways, and according to Carver caused back EMF from the speaker to get send back through the amp again. Hanging a resistor on the output of a high feedback SS amp wouldn't get all the effect. The final piece of the puzzle that got the deep enough null for Carver was reducing power output of his amp in the lower frequencies. The CJ has less power there and it caused a sound difference with those speakers in use at least. So if he is telling most of the story, the important aspects are FR with drooping power bandwidth at frequency extremes due to the use of a transformer, output impedance causing further FR differences, and the effect of that recirculation of the signal by that output impedance.

I also agree with tomelex about interpreting said results. There is an abundance of useful and thoroughly researched psycho-acoustic knowledge about how our hearing works. It isn't complete, but it is far from trivial. And in audiophile land it is ignored and we hear how we don't know anything about how our brain processes what our ears hear. Some answers are available and ignored. Here this is how your hearing works. No, no that is not it, we don't know, I am looking for how our hearing works. Really is laughable. I also agree how people argue over things easily demonstrated like at Ethan's site. And you demonstrate it and there is some vague unsubstantiated idea that we hear far better on more complex material so this simple example does not apply.

I see the humor, but nothing else. And as soon as someone looks for a scarcely documented challenge, carried with electronics of 30 years ago, I see that we are going nowhere. And taking the valuable psycho-acoustic knowledge about how our hearing works for the psycho-acoustic studies of stereo sound reproduction needed to study amplifier performance is not also a good start.

Nice no know you fully agree with Ethan. I don't. They say that when I change the cables (signal or power) of my system there should be no change in its sound. In my (and of a reasonable number of our members) humble opinion it is not true.

 

[esldude]

Esldude,

Unless you are one of these persons that considers that when we refer to magic in audiophile debates we are referring to the supernatural, I fail to see why audiophiles are between "science and superstition". Do you knock the wood every time your Aura emits a crackling sound?

BTW, I would suppose that someone would use his signature to say something about himself, not about the others . Just my opinion, YMMV.

I am not referring to when audiophiles speak of magic. I am referring to when audiophiles take action on something that could only be described as belief in something magical or metaphysical going on.

As for the sig, I guess it is a matter of perspective. I know many post their equipment to show their ideas have the merit of resolving systems or so it seems. While to me it often is a form of bragging or just a hey look at me over here sort of thing. That may or may not be what anyone is thinking. But it has always struck me that way.

Others put something in the signature to give a brief idea of how stand philosophically in an audio sense. Which is more or less how I consider mine. So much of the audiophile world is a little bit of knowledge and a little bit of cautious, superstitious activity. Along with some metaphysical thinking that seems to give many people some pleasure.

 

[esldude]

I see the humor, but nothing else. And as soon as someone looks for a scarcely documented challenge, carried with electronics of 30 years ago, I see that we are going nowhere. And taking the valuable psycho-acoustic knowledge about how our hearing works for the psycho-acoustic studies of stereo sound reproduction needed to study amplifier performance is not also a good start.

Nice no know you fully agree with Ethan and Tom. I don't. They say that when I change the cables (signal or power) of my system there should be no change in its sound. In my (and of a reasonable number of our members) humble opinion it is not true.

Well, the reason 30 year old issues still matter, is there was nothing wrong with what it told us then. And 30 years later much of the high end world still hasn't believed it. One could do it today again. Today's top tube amps are in no way beyond the abilities of SS amps.

I most definitely don't believe changing your cables changes the signal they are carrying. I have done testing, as have others, and it simply doesn't change the signal. The opinion of those to the contrary does not change that actual physical reality. I do believe you hear a change in the sound. The interesting part is since the signal electrically is unchanged why do you hear it differently?

 

[microstrip]

I am not referring to when audiophiles speak of magic. I am referring to when audiophiles take action on something that could only be described as belief in something magical or metaphysical going on.

As for the sig, I guess it is a matter of perspective. I know many post their equipment to show their ideas have the merit of resolving systems or so it seems. While to me it often is a form of bragging or just a hey look at me over here sort of thing. That may or may not be what anyone is thinking. But it has always struck me that way.

Others put something in the signature to give a brief idea of how stand philosophically in an audio sense. Which is more or less how I consider mine. So much of the audiophile world is a little bit of knowledge and a little bit of cautious, superstitious activity. Along with some metaphysical thinking that seems to give many people some pleasure.

Could you give us a few practical examples of when audiophiles take action on something that could only be described as belief in something magical or metaphysical going on? But please give us something with statistical substance and significance, not the usual cliches like The Teleportation Tweak.

 

[microstrip]

(...) As for the sig, I guess it is a matter of perspective. I know many post their equipment to show their ideas have the merit of resolving systems or so it seems. While to me it often is a form of bragging or just a hey look at me over here sort of thing. That may or may not be what anyone is thinking. But it has always struck me that way.

Others put something in the signature to give a brief idea of how stand philosophically in an audio sense. Which is more or less how I consider mine. So much of the audiophile world is a little bit of knowledge and a little bit of cautious, superstitious activity. Along with some metaphysical thinking that seems to give many people some pleasure.

I think you got the wrong idea why we post the equipment in the signature. As the great majority of members does not believe that almost everything sounds the same or occult sciences and we post in many threads about our cables, tweaks, preferences and forbidden pleasures, we find that it is nice and useful to share the composition of our equipment. For a long time I only listed it in the About section, but after we debated this aspect in a thread I understood that I would of help for the forum members.

 

[thedudeabides]

Hi elsdude,

Thanks for your response to my previous post.

Le me reiterate for the record that I am not a "techy type" when it comes to audio. That's by choice and I unabashedly fall into the "trust your ears" camp.

I can only speak for myself but my definition of an Audiophile is purposefully simplistic intentionally avoiding any inference to superstition, fear, chaos, the Twilight Zone, or cost for that matter.

For me, it is a fun and enjoyable hobby. Nothing more, nothing less.

When I do spend money on this hobby, it is typically to buy music which, to me is the essential core of being a Audiophile.

When I purchase hardware (a fairly rare occurrence since I tend to hold onto my gear for numerous years after purchase), be it amps, speakers, or whatever, it is done in a very diligent, time consuming fashion that is guided by the "cost effective" approach. I am not wealthy by any means and typically buy used equipment whenever possible. This approach has enabled me to purchase and enjoy "hi end" products that, IMHO, perform well above their price point and remain "affordable" within the relative, personal context and meaning of that term.

"Phantom like worries no one can measure and fanatical insistence such things are important"? Not me or many others, I suspect, that lie within the "subjectivist" camp when judging and ultimately purchasing audio gear.

With all due respect, I have a question for you.

I assume you listen to and enjoy music. Not being facetious but I see little evidence of this in your posts.

I assume, as part of listening to music, you have a stereo or multi-channel system and have purchased an amplifier or two in your lifetime.

After you've done your due diligence with specifications, etc. and determined that it has met all of your measurement based "criteria", did you take it home and audition it in your system to determine if its sound quality is consistent with your listening biases (assuming like most folks you have some) or did you just buy, install it, and keep it irrespective of how it actually sounded?

Or to say in a different manner, did you discover something about the sound of the amp, based on your listening experience, that was not evident or consistent with your technical research?

Best,

GG

 

[KeithR]

Well, the reason 30 year old issues still matter, is there was nothing wrong with what it told us then. And 30 years later much of the high end world still hasn't believed it. One could do it today again. Today's top tube amps are in no way beyond the abilities of SS amps.

I most definitely don't believe changing your cables changes the signal they are carrying. I have done testing, as have others, and it simply doesn't change the signal. The opinion of those to the contrary does not change that actual physical reality. I do believe you hear a change in the sound. The interesting part is since the signal electrically is unchanged why do you hear it differently?

Carvers test was in the 80s right? Fail to see why anything related 30 ys later.

And if bobs transformation was to crank up midrange and have tubby bass, thats not what tube sound is about.

 

[esldude]

Could you give us a few practical examples of when audiophiles take action on something that could only be described as belief in something magical or metaphysical going on? But please give us something with statistical substance and significance, not the usual cliches like The Teleportation Tweak.

You already have. Cables. Or we could talk jitter. Or maybe the idea LP is a reference with higher fidelity than digital. Unfortunately those are the cliches. The idea that in digital audio playback with FLAC sounds different than WAV or AIFF or that files distributed as FLAC won't sound as good as file distributed as WAV.

 

[esldude]

Hi elsdude,

Thanks for your response to my previous post.

Le me reiterate for the record that I am not a "techy type" when it comes to audio. That's by choice and I unabashedly fall into the "trust your ears" camp.

I can only speak for myself but my definition of an Audiophile is purposefully simplistic intentionally avoiding any inference to superstition, fear, chaos, the Twilight Zone, or cost for that matter.

For me, it is a fun and enjoyable hobby. Nothing more, nothing less.

When I do spend money on this hobby, it is typically to buy music which, to me is the essential core of being a Audiophile.

When I purchase hardware (a fairly rare occurrence since I tend to hold onto my gear for numerous years after purchase), be it amps, speakers, or whatever, it is done in a very diligent, time consuming fashion that is guided by the "cost effective" approach. I am not wealthy by any means and typically buy used equipment whenever possible. This approach has enabled me to purchase and enjoy "hi end" products that, IMHO, perform well above their price point and remain "affordable" within the relative, personal context and meaning of that term.

"Phantom like worries no one can measure and fanatical insistence such things are important"? Not me or many others, I suspect, that lie within the "subjectivist" camp when judging and ultimately purchasing audio gear.

With all due respect, I have a question for you.

I assume you listen to and enjoy music. Not being facetious but I see little evidence of this in your posts.

I assume, as part of listening to music, you have a stereo or multi-channel system and have purchased an amplifier or two in your lifetime.

After you've done your due diligence with specifications, etc. and determined that it has met all of your measurement based "criteria", did you take it home and audition it in your system to determine if its sound quality is consistent with your listening biases (assuming like most folks you have some) or did you just buy, install it, and keep it irrespective of how it actually sounded?

Or to say in a different manner, did you discover something about the sound of the amp, based on your listening experience, that was not evident or consistent with your technical research?

Best,

GG

Yes, of course, the old techy types don't love music stereotype. In stereo no less. Yes, I love music, listen to music, and am the kind of person interested in how things work so while not for everyone that lead me to investigate more than some because I care about the music.

For one, I haven't said amps sound the same and you can buy only on specs, (though we might if specs included tests with something other than resistive loads). But specs are important and telling. For instance an amp with a power spec at 3% is going to sound different than one spec'd at something with a zero or two after the decimal for the same power. My speakers are rather power hungry and have an impedance below an ohm in places. Making output impedance specs useful to me. So amps are more problematic for me than with some other speakers. So yes I have owned a few amps (mainly because like you I buy used). So my current amp was purchased based upon tests of it indicating it really had power and would work on tough loads. I purchased it 2nd hand never having heard any. And it has been better than expected. I also have done this same thing to find amps not up to snuff. With things other than amps and speakers the specs do seem to tell the tale. Now that includes things like tube amps that do have a sound, one I sometimes prefer.

 

[rbbert]

... The idea that in digital audio playback with FLAC sounds different than WAV or AIFF or that files distributed as FLAC won't sound as good as file distributed as WAV.

It's pretty clear that depending on your setup FLAC files might not sound as good as wav or aiff. True, not likely if your computer is less than 10 yrs old and you are using a reasonable music playing program, but you didn't put that qualification in there. As far as the last part of your statement, I doubt many people, "audiophiles" or not, believe that; those that do also keep all their money as cash in a home safe, because there's no way you could trust banks or other financial institutions if that were the case.

 

[esldude]

Carvers test was in the 80s right? Fail to see why anything related 30 ys later.

And if bobs transformation was to crank up midrange and have tubby bass, thats not what tube sound is about.

You don't understand what he did then. Do you wish to, or just looking for an excuse to discount it? Nothing related to anything 30 years later you say. I guess the way electrical signals propagate has changed in the last 3 decades. Plenty of current tube amps will have bass at least leaning toward tubby. It is an unavoidable result of a high output impedance leading to less damping of woofers. At least with some speakers it will also cause a touch less treble though that is more variable. I don't see all that much evidence the current crop of average tube amps is really much different than in the past. Certainly some examples are, and some greater variety of topologies than 30 years ago. But the great majority are the basic Williamson design with a modern PS and some modern parts. They measure about like one too in general. A design from more than 60 years ago.

 

[rbbert]

But both Stereophile and Carver later retracted the contention that the amps were indistinguishable. I don't think anyone doubts Carver's abilities as an engineer and amplifier designer (speakers, maybe), and there are quite a few examples of modern production tube amps whose sound could be mistaken for SS and vice versa.

 

[BlueFox]

I most definitely don't believe changing your cables changes the signal they are carrying. I have done testing, as have others, and it simply doesn't change the signal. The opinion of those to the contrary does not change that actual physical reality. I do believe you hear a change in the sound. The interesting part is since the signal electrically is unchanged why do you hear it differently?

Obviously, if you hear a change in sound after changing cables then the signal has changed. Just because whatever you think you are measuring hasn't changed that doesn't mean something else hasn't. Then again, perhaps the tools being used are not up to the task. For instance, did you make any DTCD measurements? I didn't think so. Who knows what other electrical properties are waiting to be discovered.

DTCD:
http://www.shunyata.com/index.php/technical-feat/technologies/78-dtcd/288-dtcd
http://www.shunyata.com/index.php/t...gies/78-dtcd/289-dtcd-measurement-comparisons

 

[esldude]

But both Stereophile and Carver later retracted the contention that the amps were indistinguishable. I don't think anyone doubts Carver's abilities as an engineer and amplifier designer (speakers, maybe), and there are quite a few examples of modern production tube amps whose sound could be mistaken for SS and vice versa.

Can you point to the retraction? Even in the reprint from 2009 they don't mention it. They did includes footnotes of details not revealed at the time. Like the speakers and amp used. One would think they would include a footnote that they later decided he had not succeeded in duplicating the sound.

 

[microstrip]

You already have. Cables. Or we could talk jitter. Or maybe the idea LP is a reference with higher fidelity than digital. Unfortunately those are the cliches. The idea that in digital audio playback with FLAC sounds different than WAV or AIFF or that files distributed as FLAC won't sound as good as file distributed as WAV.

OK. It is now clear that you consider, if they exist, the differences caused by cables or jitter have a supernatural causality (just using the wikipedia definition of superstition). The idea that the LP can sound more real music to people (and here we just debating the semantics of what means "higher fidelity") has nothing to do with the superstition or science, it is an preference - perhaps a group preference. Considering the digital arguments, it is clear that you are mixing those who have some technical reasons to support them in most cases with those who are simply due to ignorance of people. IMHO you need a lot more and better arguments before suggesting that audiophiles are superstitious. IMHO you are confusing the weaknesses and limitations of empirical knowledge with superstition.

BTW, do you consider Philip Newell, the author of "Recording Studio Design" a superstitious guy? The same to all those people who wrote tens of articles on the effect of jitter?

 

[rbbert]

My bad, I was confusing the follow-up with the production amp, which even Carver admitted was easily distinguishable from the C-J.

 

[microstrip]

Yes, of course, the old techy types don't love music stereotype. In stereo no less. Yes, I love music, listen to music, and am the kind of person interested in how things work so while not for everyone that lead me to investigate more than some because I care about the music.

For one, I haven't said amps sound the same and you can buy only on specs, (though we might if specs included tests with something other than resistive loads). But specs are important and telling. For instance an amp with a power spec at 3% is going to sound different than one spec'd at something with a zero or two after the decimal for the same power. My speakers are rather power hungry and have an impedance below an ohm in places. Making output impedance specs useful to me. So amps are more problematic for me than with some other speakers. So yes I have owned a few amps (mainly because like you I buy used). So my current amp was purchased based upon tests of it indicating it really had power and would work on tough loads. I purchased it 2nd hand never having heard any. And it has been better than expected. I also have done this same thing to find amps not up to snuff. With things other than amps and speakers the specs do seem to tell the tale. Now that includes things like tube amps that do have a sound, one I sometimes prefer.

Have you measured the impedance, phase and efficiency of your Soundlab Aura speakers? Can you tell us what specification set you used to choose your amplifier? As far as I could see almost all the specifications available in the manufacturer site of the ST500 would receive a red warning according to the AudioPrecision white paper "How to write (and read) audio specifications". This surely does not mean that the amplifier is not excellent value for money - and I hope that you are not going to tell us you got it based on TheAbsoluteSound awards.