Can you hear a difference in Sound between Audio Amplifiers?

[Irvrobinson]

There is little room for art in electronic circuitry.

I think you've gone too far with this remark. There is room for art, and it's called innovation. There are also numerous design decisions that an engineer can make, but in theory at some level they're all correct. I suppose one could argue that beyond a certain point of good design none of these decisions matter, and that's a perfectly legitimate position, but that's not what you seem to be arguing.

 

[Gordonj]

While i don't believe in spending the big money some spend on home amps (because I don't believe there is a difference) but I do beleive that each amp manufacture has different tonal characteristics.

 

[Irvrobinson]

While i don't believe in spending the big money some spend on home amps (because I don't believe there is a difference) but I do beleive that each amp manufacture has different tonal characteristics.

Wow. That's quite a leap, and that should be measurable. The only way that seems to occur is if the amp has an output stage with output stage load characteristics that vary by frequency, like a tube amp without an output transformer. The solid state amps we're discussing generally don't have those characteristics, or do you think they have unique tonal characteristics even though we can't measure the differences?

 

[mtrycrafts]

... (because I don't believe there is a difference) but I do beleive that each amp manufacture has different tonal characteristics.

One contradicts the other, yes?

 

[PENG]

I think you've gone too far with this remark.

That seems a little harsh, I was trying to make a point, and did say "little" room, not "no" room. Still, point well taken.

There is room for art, and it's called innovation.

Innovation, I absolutely agree but I wouldn't have considered that as "art" but I am sure I could have, so again, fair point.

There are also numerous design decisions that an engineer can make, but in theory at some level they're all correct. I suppose one could argue that beyond a certain point of good design none of these decisions matter, and that's a perfectly legitimate position, but that's not what you seem to be arguing.

I fully agree, and I should clarify that when I said electronic circuitry I meant only those apply to audio amplifiers. Audio amplifier circuitry designs are a mature product and they really don't require rocket scientists or even PhDs in EE, physics etc. In fact, I suspect most of them are designed by non degree engineers and technologists. I am not going to take it to the extreme (not this time) to say that they are also designed by hobbyists with no technical background because those typically just pick a design, build them as is or do some tweaking themselves to their likings.

PhD's in EE, physics, rocket science wouldn't bother as they would know that the theories behind are well understood and not challenging enough for them nor would they see any need to do anything since they know any improvements would be academic that it won't benefit anyone except those die hard self indulging hifi nuts. Even if they are asked to do something, they would trust what they see on the spectrum analyzers, scopes, high speed recorders etc., take a peek at existing technical papers, or review available waveform analysis and would soon realize their is no point. No doubt there are room for innovation such as to develop ways to further improve on efficiency while not sacrificing accuracy, but that's another topic.

 

[RichB]

There seem to be two camps here comparing well built amps operating within their limits.

1) The differences are small and not significant.
3) The differences can be significant driving real speaker loads. So while the standard tests measurements do not fully determine the performance in a system.

The next problem is testing the above hypotheses.
There are basically two views here as well:

A) A listening test cannot be executed that would be valid because subjectivity, room acoustics, and/or speaker interaction.
B) A listening test could be conducted that would be valid if you selecting the proper attendees, speakers, and amps.

So we can now group the views here:

1A) Not significant and cannot be tested.
1B) Not significant and can be tested
2A) Could be significant and cannot be tested
2B) Could be significant and can be tested

I am a class 2B but I depending on the metrology and speaker selection.

I wonder if you could remove the people from the equation by using measurement software like REW and a representative set of speakers.

- Equalize the volume with test tones.
- Play as selection of music.
- Obtain the traces.
- Plot them on the same graph and time align.

- Rich

 

[PENG]

There seem to be two camps here comparing well built amps operating within their limits.

1) The differences are small and not significant.
3) The differences can be significant driving real speaker loads. So while the standard tests measurements do not fully determine the performance in a system.

The next problem is testing the above hypotheses.
There are basically two views here as well:

A) A listening test cannot be executed that would be valid because subjectivity, room acoustics, and/or speaker interaction.
B) A listening test could be conducted that would be valid if you selecting the proper attendees, speakers, and amps.

So we can now group the views here:

1A) Not significant and cannot be tested.
1B) Not significant and can be tested
2A) Could be significant and cannot be tested
2B) Could be significant and can be tested

I am a class 2B but I depending on the metrology and speaker selection.

I wonder if you could remove the people from the equation by using measurement software like REW and a representative set of speakers.

- Equalize the volume with test tones.
- Play as selection of music.
- Obtain the traces.
- Plot them on the same graph and time align.

- Rich

Rich, you use the term "views", that's great because views are just views, not necessarily facts. Now, why do you think (again, I understand it is just your view) amps affect SQ significantly when if you keep in mind that using real world material, the sound would have been throught so many things including mics, all sorts of cabling, connectors, acoustic effects, processing, recording equipment, mastering, media players and I am sure I missing a few along the way already, and then more cabling, preamp, amp, and finally the speakers and the specific acoustic environment that different speakers may adapt differently?

My point, is, with so many things in the path from the original sound to our ears/brains via the speakers and the acoustic environment they are in, yet somehow we think we could single out the influence of the amp as "significant (audibly that is)"? To be clear, you may group me in 1) but only if you quality 1) with the conditions that the amps being compared are well designed for accuracy/neutrality and verified by currently available measuring criteria that include, but not limited to flat freq response, low output impedance, high enough damping factor, good transient response, low THD+noise, low impedance drive capability, and such amps will be driving speakers of typical/average load such as 4 to 8 ohms nominal with no dips below 3 ohms, and not more reactive than 60 degress lagging or leading. When I use terms such as flat, low, high, I realize they may be hard to define, but let's say they mean above average among the major brands for our discussion, if you have better ways to define those terms, feel free to substitute.

Examples of amps that I would use for comparisons would be mid range AVR amps such as Denon 3XXX series, Yamaha RX-A XXXX series, Emotiva XPA-2 and above, Anthem, ATI, Bryston, Parasound, Krell, Marantz, just to name a few. Without a little more specifics, I don't feel I could be group into the 4 you listed, but I appreciate your attempt, as judging by our posts we are all over the map on this topic, what a mess.

 

[RichB]

^^^

Thanks. Great Amp selection.
You know a great deal more about amps than I do

I was trying to simplify or break down the problem to help determine a coarse of action and
to clarify the human aspect of the test and this thread to see if that helps.

I have a friend who likes to mix his own music.
He is constantly telling me, if you knew all the crap, compression, distortion and that went into the recording and the mixing, you would stop worrying about your amp
Intellectually, I know he is right. But this is an problem bordering on OCD

To all of that, I say, your are right but that does not mean that I should not have a great room, speakers, preamp, and an amp to do the best job possible (within my budget) with the source. No matter how it got here.

As a software guy, I try to define the requirements, identify decision points, and get started.
Basically to create order form chaos in order get done.

So when approaching my system, this is my checklist:

- Room: Check, it sounds great. I have a OmniMic someday I will measure it
- Speakers: Check - Revels sound good and I do not have money upgrade.
- Source: Check - I am happy with Oppo BDP-105 analog outs
- Preamp: Check - I am happy with the Marantz AV8801 in Pure Direct mode (10 tries at Audyssey, Not interested)
- AMP: Check, erase, check, erase, repeat...- I have heard differences, could be bad science, must learn more, crap too many opinions.
Interim Solution - Buy big good-value iron with decent aesthetics with lots of power. AKA: ATI 3005.

I trust the science but I am not sure if the measurement set is complete for all amp types.
So, I am here

- Rich

 

[PENG]

^^^


So when approaching my system, this is my checklist:


- Speakers: Check - Revels sound good and I do not have money upgrade.
- Source: Check - I am happy with Oppo BDP-105 analog outs
- Preamp: Check - I am happy with the Marantz AV8801 in Pure Direct mode (10 tries at Audyssey, Not interested)

- Rich

When I bought my R900 for my newly acquired Marantz 7 pairs I almost opted for the F32 in the last minute so I know what your mean. Which model do you have?
I am also happy with the Oppo 105, I can no longer hear the fan of my ex 95.
Good to know you are happy with the A8801, that's the one I am going to get as soon as I can get rid of my AV7005. I am expecting SQ improvements but I want the XT32, and it is also just that I've got to have their flag ship now that it is available.

 

[PENG]

^^^

I have a friend who likes to mix his own music.
He is constantly telling me, if you knew all the crap, compression, distortion and that went into the recording and the mixing

Sorry about getting off topics guys, but just want to say that no amps can fix this one and for me so I will pay $100 to buy any Adele's BR, Flac, CD, Vinyl or whatever format if anyone has a recording that is free from vocal distortion. I can't get over the claim by ADTG, who owns so many high end gear that he could not hear her distorted voice (recording). I really love her songs/singing but that little distortion at the end of some lines is a major distraction to me. Too bad the recording, mixing, producing team is getting away with such irresponsbile work as they are selling so well because of Adele, and only Adele herself.

 

[AcuDefTechGuy]

Sorry about getting off topics guys, but just want to say that no amps can fix this one and for me so I will pay $100 to buy any Adele's BR, Flac, CD, Vinyl or whatever format if anyone has a recording that is free from vocal distortion. I can't get over the claim by ADTG, who owns so many high end gear that he could not hear her distorted voice (recording). I really love her songs/singing but that little distortion at the end of some lines is a major distraction to me. Too bad the recording, mixing, producing team is getting away with such irresponsbile work as they are selling so well because of Adele, and only Adele herself.

I'm just not as picky as you. Or maybe I'm just in denial. Or my hearing just isn't as sensitive.

 

[PENG]

I'm just not as picky as you. Or maybe I'm just in denial. Or my hearing just isn't as sensitive.

If this is a multiple choice test I take the denial one. I know it because if you like the music a lot (such as that Yo-Yo ennio one with little DR, remember?), you indulge yourself so much that you wouldn't notice those little things. That happens to me too but I guess to a lesser extent. That may also be the reason why you can't hear differences between your amps, now of course I am just kidding..

 

[RichB]

Sorry about getting off topics guys, but just want to say that no amps can fix this one and for me so I will pay $100 to buy any Adele's BR, Flac, CD, Vinyl or whatever format if anyone has a recording that is free from vocal distortion. I can't get over the claim by ADTG, who owns so many high end gear that he could not hear her distorted voice (recording). I really love her songs/singing but that little distortion at the end of some lines is a major distraction to me. Too bad the recording, mixing, producing team is getting away with such irresponsbile work as they are selling so well because of Adele, and only Adele herself.

Yep, The Adele CD's I have I use to test for harshness
I recently starting ripping my CD collection and you can almost date the CD's by listening to the quality or lack there of.
The 10,000 maniac's CD is a crime against all that is holy

- Rich

 

[RichB]

When I bought my R900 for my newly acquired Marantz 7 pairs I almost opted for the F32 in the last minute so I know what your mean. Which model do you have?
I am also happy with the Oppo 105, I can no longer hear the fan of my ex 95.
Good to know you are happy with the A8801, that's the one I am going to get as soon as I can get rid of my AV7005. I am expecting SQ improvements but I want the XT32, and it is also just that I've got to have their flag ship now that it is available.

I have Revel Salons (front), Studios (rear), and Voice (Center).
Right now, I am using the Outlaw 7500 which is a very amp.
I wonder what I am doing thinking about replacing it

Oh yeah, Power, I must have more POWER

I am the wrong guy to talk to about XT32, I limit all processing because it seems to alter the sound stage.
There is no science behind this statement. I just sit 6 feet from both Salons and listen to the apparent position the sounds.

The AV8801 is a good preamp and there are some ways to get decent deals on them.
eBay is your friend

- Rich

 

[psbfan9]

I really should stay out of this, but I can't help myself.

Below is a quote from a well respected, professional reviewer. To me, it sounds as if he is saying there's a difference in sound between two amps.

"I had a brief chance to directly compare the two in a not so ideal listening environment on their new tower speakers. The sonic differences were subtle (as is the case with all well designed amplifiers operating within their linear region) but interesting to note nonetheless. Overall I found both amplifiers excelled sonically, but felt the XPA-2 was simply more lively and bold while the RPA-2 favored a more delicate presentation with less graininess at low power levels."

 

[RichB]

I do not think Audioholics like Outlaws.
Outlaws are always kicking them and spitting on them as they lie drunk in the mud.
This explains the lack of reviews.

ATI is well known to hang with Outlaws so they must also be shunned.

- Rich

 

[AcuDefTechGuy]

If this is a multiple choice test I take the denial one. I know it because if you like the music a lot (such as that Yo-Yo ennio one with little DR, remember?), you indulge yourself so much that you wouldn't notice those little things. That happens to me too but I guess to a lesser extent. That may also be the reason why you can't hear differences between your amps, now of course I am just kidding..

I hear no dynamic compression on Yo-Yo Ma Plays Ennio Morricone. Fabulous I say.

I think you just gave our "enemy" ammunition to use against us - the denial syndrome.

I think I'm in denial too; nothing could possibly sound distorted coming through my system!

 

[Irvrobinson]

My point, is, with so many things in the path from the original sound to our ears/brains via the speakers and the acoustic environment they are in, yet somehow we think we could single out the influence of the amp as "significant (audibly that is)"?

Yes, for multiple reasons. One, because we can't compare the recording to the original performance, assuming there was an original performance to listen to, and there often isn't. So whatever the recording happens to be becomes the reference.

Two, most of the influences you've mentioned, namely cables and connectors, don't have a sonic signature, either measurable or audible.

Three, the active signal path components in a recording chain are, for the most part, balanced, line-level amplifiers and processors that use standard 600ohm interfaces, and have circuits mostly built from ICs. These sorts of components are cheaper and easier to build to meet consistent specifications than high-performance amplifiers that have to drive speakers that present seemingly arbitrary loads.

Of course, arguing for entertainment aside, I still believe that these comparison tests will show that the test subjects won't be able to tell the amplifiers apart, and some of us will still feel enough preference for some amps over other amps - when we are not looking to have a preference - that we'll still end up making purchase decisions based on factors we can't objectively prove are valid.

 

[PENG]

I have Revel Salons (front), Studios (rear), and Voice (Center).
Right now, I am using the Outlaw 7500 which is a very amp.
I wonder what I am doing thinking about replacing it

Oh yeah, Power, I must have more POWER

I am the wrong guy to talk to about XT32, I limit all processing because it seems to alter the sound stage.
There is no science behind this statement. I just sit 6 feet from both Salons and listen to the apparent position the sounds.

The AV8801 is a good preamp and there are some ways to get decent deals on them.
eBay is your friend

- Rich

So you have the ultimate speakers, good for you. I use pure direct for music listening and only use Audyssey for movies. Regarding the 8801 you are right they are deals out there and I am getting one soon.

 

[PENG]

Yes, for multiple reasons. One, because we can't compare the recording to the original performance, assuming there was an original performance to listen to, and there often isn't. So whatever the recording happens to be becomes the reference.

Two, most of the influences you've mentioned, namely cables and connectors, don't have a sonic signature, either measurable or audible.

Three, the active signal path components in a recording chain are, for the most part, balanced, line-level amplifiers and processors that use standard 600ohm interfaces, and have circuits mostly built from ICs. These sorts of components are cheaper and easier to build to meet consistent specifications than high-performance amplifiers that have to drive speakers that present seemingly arbitrary loads.

Of course, arguing for entertainment aside, I still believe that these comparison tests will show that the test subjects won't be able to tell the amplifiers apart, and some of us will still feel enough preference for some amps over other amps - when we are not looking to have a preference - that we'll still end up making purchase decisions based on factors we can't objectively prove are valid.

Sounds reasonable to me, so I have to agree.