Can you hear a difference in Sound between Audio Amplifiers?

[Auditor55]

No, they do not all sound the same under different loads, and its fanciful to expect that they would and will. Amplifiers are tested with resistive loads, and is therefore limited in telling you how it will drive a given loudspeaker. Very few amp manufacturers actually test their amps under varying condition of load. This was another point that Peter Walker made continuously. For one thing source impedance varies from amp to amp, and those with a higher source impedance will sound more different under varying loads than one that has a very low source impedance. That is one reason that I am keen on Quad amps, as they have a very low source impedance.

In comparison to this issue, measuring amps for minute levels of distortion connected to a resistor gives very limited information. That is what you would expect the way impedance curves look and then even more to the point look at phase angles. When these get to negative 45 then there are huge differences in true and apparent shifts resulting in large current fluxes. To think that all amps will act similarly to these situations is absurd in the extreme. So no all amps do not sound the same. Not by a long shot.

Do you agree that two amps that measure the same should sound the same? Or whatever audible differences claimed between amps should be measurable?

 

[AcuDefTechGuy]

Do you agree that two amps that measure the same should sound the same? Or whatever audible differences claimed between amps should be measurable?

I would say that 2 amps that are both HIGH QUALITY will both sound equally GREAT.

 

[RichB]

No, they do not all sound the same under different loads, and its fanciful to expect that they would and will. Amplifiers are tested with resistive loads, and is therefore limited in telling you how it will drive a given loudspeaker. Very few amp manufacturers actually test their amps under varying condition of load. This was another point that Peter Walker made continuously. For one thing source impedance varies from amp to amp, and those with a higher source impedance will sound more different under varying loads than one that has a very low source impedance. That is one reason that I am keen on Quad amps, as they have a very low source impedance.

In comparison to this issue, measuring amps for minute levels of distortion connected to a resistor gives very limited information. That is what you would expect the way impedance curves look and then even more to the point look at phase angles. When these get to negative 45 then there are huge differences in true and apparent shifts resulting in large current fluxes. To think that all amps will act similarly to these situations is absurd in the extreme. So no all amps do not sound the same. Not by a long shot.

Do you agree that two amps that measure the same should sound the same? Or whatever audible differences claimed between amps should be measurable?

Height, width, and depth measurements certainly don't matter, though some think they do
Is there any technical disagreement with the @TLS Guy post?

- Rich

 

[Auditor55]

I would say that 2 amps that are both HIGH QUALITY will both sound equally GREAT.

But Quality is not always proportional to Price. For example, a $10K amp isn't always better quality than a $5K amp.

Do you agree that HIGH QUALITY and high fidelity are one in the same?

 

[Auditor55]

Height, width, and depth measurements certainly don't matter, though some think they do
Is there any technical disagreement with the @TLS Guy post?

- Rich

I think TLS Guy brought up his preference for Tube amps. I don't know much about them just that they scare me. I'm scare they might blow an release some kind of toxic aerosol into the air.

 

[AcuDefTechGuy]

Do you agree that HIGH QUALITY and high fidelity are one in the same?

Yep. High quality = high fidelity = Hi-Fi = audiophile amps.

 

[Pogre]

No, they do not all sound the same under different loads, and its fanciful to expect that they would and will. Amplifiers are tested with resistive loads, and is therefore limited in telling you how it will drive a given loudspeaker. Very few amp manufacturers actually test their amps under varying condition of load. This was another point that Peter Walker made continuously. For one thing source impedance varies from amp to amp, and those with a higher source impedance will sound more different under varying loads than one that has a very low source impedance. That is one reason that I am keen on Quad amps, as they have a very low source impedance.

In comparison to this issue, measuring amps for minute levels of distortion connected to a resistor gives very limited information. That is what you would expect the way impedance curves look and then even more to the point look at phase angles. When these get to negative 45 then there are huge differences in true and apparent shifts resulting in large current fluxes. To think that all amps will act similarly to these situations is absurd in the extreme. So no all amps do not sound the same. Not by a long shot.

If what you're saying is that some amps will crap out under a tough load and not sound very good I agree. That would be operating outside what it's capable of doing, right? Whether or not it should be capable is another subject, imo.

 

[KEW]

Is there any technical disagreement with the @TLS Guy post?

Not from me, but I have always included (though not consistently stated, as I should) the provision that the amp is operating within its design capability and would tend to categorize the situation he speaks of as speakers having special demands that approach or exceed the amplifier's design capabilities. Certainly, if you are driving speakers like Gene's Status Acoustics 8T's you cannot just grab any old amp off of the shelf!
Certain speakers, like Maggies, have an established reputation for requiring a more capable amp than most.
This is a gap or flaw in "the system" which we have seen surface here on occassion! Polk comes to mind as one I have read about recently on this forum where the speakers are actually quite demanding; however, the speakers are being sold through Best Buy "bulk commodity" stores that do not make an effort to inform the buyer.
I always assume that if you are buying Status Acoustic 8T's, somewhere along the way, someone from SA or your sales rep is going to have a conversation about what amp you will use with them.
Now, I may not fully understand what TLSGuy is saying! Is he saying that even if amps are not being pushed to their limits they will still have different sound characteristics while under a situation that is easily sustainable?
In that case, tell me more (including how this characteristic might, or why it couldn't be measured)!

 

[Auditor55]

Yep. High quality = high fidelity = Hi-Fi = audiophile amps.

"The main reason to measure audio is to learn if a device is good enough to sound transparent. All transparent devices by definition by definition sound the same because they don't change to sound enough to be noticed even when listened carefully" [Ethan Winer -AES Damn Lies Workshop]

Do you agree, particularly in regards to amplifiers, with the above statement?

Do you agree that high fidelity is synonymous with audio transparency?

 

[Auditor55]

"High fidelity (often shortened to hi-fi or hifi) is a term used by listeners, audiophiles and home audio enthusiasts to refer to high-quality reproduction of sound. ... Ideally, high-fidelity equipment has inaudible noise and distortion, and a flat (neutral, uncolored) frequency response within the human hearing range." [Wikipedia]

Again, in view of the subject of this thread, I ask a related question, should amplifiers sound the same?

 

[Mikado463]

Again, in view of the subject of this thread, I ask a related question, should amplifiers sound the same?

Wow, this thread is over 7 years old, if you go back to the beginning, read and focus on the 'subject' the answer is simple........yes they 'can' sound different. IMO, Gene has explained it very well. I think way too many of you are trying to overthink the topic just so as to justify your belief and come up with way too many caveats.

 

[TLS Guy]

I think TLS Guy brought up his preference for Tube amps. I don't know much about them just that they scare me. I'm scare they might blow an release some kind of toxic aerosol into the air.

That is not true. I do not actually like tube amps precisely because they have a very high source resistance..

 

[TLS Guy]

Do you agree that two amps that measure the same should sound the same? Or whatever audible differences claimed between amps should be measurable?

Yes, but there is a problem. It actually is very difficult to actually measure an amp under the type of load a speaker offers on the bench. So the quickest short cut is a measurement of the amps source resistance. Current methods of measuring amps are actually of questionable value. THD under resistive load condition are of very limited value. Peter Walker showed years ago when he unknowing to a listening panel gradually raised THD. They did not notice until it was around 4% THD. So there is far too much reliance on THD for determining how an amp will actually sound.

Unless you buy Magnepan speakers you will not really have a good handle on how your amp will perform with your speakers or others. That really is a good argument for active design and making amp and speaker one integral unit from a design standpoint.

So amps can and do sound different under loading conditions. Loudspeaker loads are all over the map, in terns of impedance and phase angles especially.

So for me a low source resistance is a matter of great importance especially from the pint of view of speakers design, as I have less worry of load to amp matching.

So there is something to amp and speaker matching, and that is especially true of tube amps.

 

[Mikado463]

Agreed 'Doc', thus the word synergy does in fact come into play ..........

 

[lovinthehd]

So, concentrating on the new posts from those saying amps sound different to them in their use, how about some examples of such "synergy" between particular speakers and particular amps? How did you determine and compare such? What were the "symptoms" of a superior combination? Just solid state, no tubes, to keep it relatively simple.

 

[ATLAudio]

Synergy with a speaker, ok, how about with different media? This whole synergy claim assumes all media has the same approach to recording and mastering and that’s not remotely the case. I’ve seen amps measure transparently, and with subtle coloration. The coloration variety in different records isn’t subtle. It’s gargantuan, just like speaker variety. That subtle coloration synergy is spit in the ocean.

I don’t believe all amps sound the same, but the all the transparent ones do, and that is relatively cheap, easy to make, and fairly common.


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[Pogre]

So amps can and do sound different under loading conditions. Loudspeaker loads are all over the map, in terns of impedance and phase angles

I guess I wasn't specific enough so that's my fault. Of course some wonky, real world speakers that present difficult loads can affect an amp's performance. I know there are circumstances where matching an amp to a speaker can make a big difference. When I say "they should sound the same" I mean it when both are operated within spec, level matched, controlled, etc., and certainly wasn't including tube amps. I know an amp rated for 8 ohms wouldn't do well with speakers that are all over the place in impedance and crazy phase angles. That's why I would never suggest all amps sound the same without at least a few qualifiers. Special needs speakers like the ones you're talking about need special amplification.

Personally, I'm buying speakers that (hopefully) won't require any special amplification and should sound pretty much the same on any decent amp, provided conditions are equal (no processing) and operated within spec and design parameters.

 

[Pogre]

No, they do not all sound the same under different loads, and its fanciful to expect that they would and will.

And you know... I did say "within spec". Not "with any speaker under any loads no matter what the amp is rated to handle". You added that and quoted me like I said it...

 

[TLS Guy]

I guess I wasn't specific enough so that's my fault. Of course some wonky, real world speakers that present difficult loads can affect an amp's performance. I know there are circumstances where matching an amp to a speaker can make a big difference. When I say "they should sound the same" I mean it when both are operated within spec, level matched, controlled, etc., and certainly wasn't including tube amps. I know an amp rated for 8 ohms wouldn't do well with speakers that are all over the place in impedance and crazy phase angles. That's why I would never suggest all amps sound the same without at least a few qualifiers. Special needs speakers like the ones you're talking about need special amplification.

Personally, I'm buying speakers that (hopefully) won't require any special amplification and should sound pretty much the same on any decent amp, provided conditions are equal (no processing) and operated within spec and design parameters.
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The problem is that you actually know the impedance and phase angles of few speakers. An awful lot of speakers have worse curves than you imagine. There is a good reason most don't want you to see it, and use jargon like 8 ohm compatible. My experience is that more speakers are fairly difficult loads than easy. I well remember that Phil's B & Ws he had in Grand Forks sounded quite harsh with his Perreaux amp, but the HF much smoother with Quad. In particular a three way speaker is far more likely to be a difficult load than not.

This goes to the issue of not only sound quality, but also reliability, especially of receivers. An amp that can handle difficult loads well is much more likely to have a long life. I can tell you that amps not fussy about the load they are driving trend to the much more reliable.

 

[Mikado463]

I know an amp rated for 8 ohms wouldn't do well with speakers that are all over the place in impedance and crazy phase angles.

not necessarily true, whereas a 8 ohm rating is the defacto 'norm' , it's the amps ability to double down(or thereabouts) and remain stable into 4 and even 2 ohm loads that tells of it's ability to handle complex load scenarios.

Lovin ask for an example of synergy and matching of amps to ones speaker choice, 'stats'. Electrostatic speakers present a highly capacitive 'look' to them, combined with an inverse impedance map to conventional 'cone' speakers the selection of amp and speaker wire all comes into play