Can you hear a difference in Sound between Audio Amplifiers?

[dpattillo]

It's been done: The ButtKicker

- Rich

How about a spring loaded hammer that whacks the back or bottom of your chair during intense movie scenes.

 

[perpetualglass]

I can't hear any difference among amps when they are level matched and driven within spec.

This!

 

[goodman]

I've heard a difference between an inexpensive receiver and one that cost twenty times more. When I turned the level up, the inexpensive receiver sounded harsh, while the expensive one did not. I attributed the difference to amplifier power, but this is only a guess. I also compared an old tube amp and preamp that had lain around for years, and while it did not sound harsh, it could only produce a low volume. With top quality amplifiers, I doubt very much if I would be able to discern a difference.

 

[AcuDefTechGuy]

I've heard a difference between an inexpensive receiver and one that cost twenty times more. When I turned the level up, the inexpensive receiver sounded harsh, while the expensive one did not. I attributed the difference to amplifier power, but this is only a guess. I also compared an old tube amp and preamp that had lain around for years, and while it did not sound harsh, it could only produce a low volume. With top quality amplifiers, I doubt very much if I would be able to discern a difference.

Receivers are processors. Unless you use Pure Direct / Direct mode, the sound may sound differently.

In addition, AVRs are like PCs. Some firmware updates or internal programming may implement bass management differently among other things. Bottom one, processors are complex microprocessors, and they can sound differently.

 

[internetmin]

I throw my hat into the differences arena. For sure, I've heard it in an A/B comparison with some receivers I was testing out. I've heard it with an A/B of three receivers at a dealer and I've also heard it at my house. I have an old NAD integrated and also a 10 year old Marantz receiver. The NAD, rated at 1/2 the power of the Marantz, sounds better. It's absolutely not night and day, but there is a difference. The NAD somehow sounds a bit smoother, more liquid, more natural and the Marantz has a slightly more collapsed and flatter soundstage. I concede that I'm talking about a larger system chain with a receiver and integrated as opposed to just an amp.

 

[AcuDefTechGuy]

I throw my hat into the differences arena. For sure, I've heard it in an A/B comparison with some receivers I was testing out. I've heard it with an A/B of three receivers at a dealer and I've also heard it at my house. I have an old NAD integrated and also a 10 year old Marantz receiver. The NAD, rated at 1/2 the power of the Marantz, sounds better. It's absolutely not night and day, but there is a difference. The NAD somehow sounds a bit smoother, more liquid, more natural and the Marantz has a slightly more collapsed and flatter soundstage. I concede that I'm talking about a larger system chain with a receiver and integrated as opposed to just an amp.

You believe the difference among processors (AVR/ pre-pro) is more significant than the difference among amps of the same power rating ?

If so, The Audio Critic would agree with you. I would agree with you. Many people would agree with you. Some would disagree.

 

[fmw]

The problem, Min, is level matching and a blind test. Level matching has to be done with a volt meter, not your ears. Blind testing requires you not to know which unit is playing at any given time. Without level matching, a slight difference in volume will make a noticeable difference to the ear. If the test isn't blind, then bias gets involved. If you expect the NAD to sound better than the Marantz, then it will. Basic human psychology. We did our tests with a panel of 10 audiophiles - everything double blind and level matched. At the time I was using a fancy Audio Research tube amp in my two channel system. Great amp because the panel couldn't detect an audible difference between it and the solid state amps. It just goes to show how well the engineers can design a tube amp if they want to. The only amp we were able to detect a sonic difference with was a low power single ended triode tube amp and the amp in a Sony Walkman which was obviously underpowered for driving a pair of B&W 802's. There were certainly random results from all the solid state amps. Random means the listeners on average weren't able to tell one amp from another.

 

[AcuDefTechGuy]

The problem, Min, is level matching and a blind test.

The Audio Critic religiously preached level-matching & blind testing as much as anyone. And they believed processors can sound differently.

 

[internetmin]

You believe the difference among processors (AVR/ pre-pro) is more significant than the difference among amps of the same power rating ?

If so, The Audio Critic would agree with you. I would agree with you. Many people would agree with you. Some would disagree.

I can only relate what my experience has been. I'm a huge fan of Floyd Toole's work, so I tend to give more credence to tests and when they are connected to a switcher with an A/B. As a result, I'm less inclined to believe the hype about a speaker sounding like X or Y or Z in one dealer or room and then another speaker sounding like A or B or C in another room or dealer and then those experiences being absolutes for some people. The overall system chain and the psychoacoutics of the room and the unreliability of audible memory all play a role for me.

The passion for products and the differences with components, etc. reminded me of something I had read in Stereophile in 2012. I want to share this with everyone. It stuck with me. Michael Kay was the founder of Lyric HiFi in NYC and what I really appreciate is his passion for music. I don't think anyone can claim passion for music and sound systems like this man lived. This guy was out of control passionate: NOT selling a component to a customer because he felt he wouldn't hear a difference and hand-selecting components for an event at Lyric with a singer to bring out the ambiance of the evening, and spending a MILLION DOLLARS to custom-design a room and physically isolate it from the effects of the NYC subway!?. That's the passion. These are good reads.

Where the Rubber Meets the Road Michael Kay of Lyric Hi-Fi & Video | Stereophile.com
Lyric HiFi & Video - Lyric HiFi & Video
Mike Kay 1923–2012 | Stereophile.com

 

[internetmin]

Check out this comment in the post here: Mike Kay 1923–2012 | Stereophile.com. Just great stuff, great passion:

As a junior member of a metro NY area rep firm, I got all the good jobs. One of them was taking Amanda McBroom around to see some of the retail establishments selling Sheffield Labs recordings. At the end of a long afternoon, Amanda and I ended up at Lyric and it was then that I learned what an incredible salesman Mike Kay was.
Knowing that Amanda was on her way to the store, Mike orchestrated a demonstration to end all demonstrations. The system he assembled included the Infinity IRS columns. The turntable, cartridge, and electronics? Ask someone else, I certainly don't remember. Nor do I have to. But I will never forget the incredible graciousness Mike showed to Amanda, his low-key but authoritative explanation of why he chose these components for the demo, why he wanted her to hear her voice singing her song "The Rose." Amanda's jaw dropped as the last notes faded.
I was transfixed. I heard nuances from those speakers I had never heard before. And I had played that song on many, many other systems, some of them world-class in their time.
It was my first introduction to the full force of "the Mike Kay difference" and it was then that I saw his contribution to our industry. I had just been exposed to the smoothest, most cosmopolitan presentation of technology in the service of music I could then imagine. Nothing I have seen or heard since has surpassed that afternoon.
Granted, Mike could be a real pain in the butt to a junior rep. (He had once told another manufacturer that I needn't call on the store because I couldn't do anything for him.) And I knew all the legends of his inviting the "unworthy" to leave his establishment.
But that afternoon, I saw genius. I know some will scoff at this description. To them, I say only "You weren't there."

 

[AcuDefTechGuy]

I can only relate what my experience has been. I'm a huge fan of Floyd Toole's work, so I tend to give more credence to tests and when they are connected to a switcher with an A/B. As a result, I'm less inclined to believe the hype about a speaker sounding like X or Y or Z in one dealer or room and then another speaker sounding like A or B or C in another room or dealer and then those experiences being absolutes for some people. The overall system chain and the psychoacoutics of the room and the unreliability of audible memory all play a role for me.

I agree.

But as you say, some people think their personal experiences are absolute - that if you don't agree with their own personal "findings", then you must be doing something wrong!

Because they can't be wrong!

 

[internetmin]

I agree.

But as you say, some people think their personal experiences are absolute - that if you don't agree with their own personal "findings", then you must be doing something wrong!

Because they can't be wrong!

LOL! Seriously, if someone can prove me wrong, then more power to them. I don't have an ego that needs stroking and if I make a mistake, I appreciate the correction and even more appreciate the opportunity to grow through learning. If we're not all willing to be open minded and learn, then that's a much bigger problem than getting all the levels correct

 

[fmw]

The Audio Critic religiously preached level-matching & blind testing as much as anyone. And they believed processors can sound differently.

I agree. We're talking about amplifiers, not processors.

 

[fmw]

I can only relate what my experience has been. I'm a huge fan of Floyd Toole's work, so I tend to give more credence to tests and when they are connected to a switcher with an A/B. As a result, I'm less inclined to believe the hype about a speaker sounding like X or Y or Z in one dealer or room and then another speaker sounding like A or B or C in another room or dealer and then those experiences being absolutes for some people. The overall system chain and the psychoacoutics of the room and the unreliability of audible memory all play a role for me.

The passion for products and the differences with components, etc. reminded me of something I had read in Stereophile in 2012. I want to share this with everyone. It stuck with me. Michael Kay was the founder of Lyric HiFi in NYC and what I really appreciate is his passion for music. I don't think anyone can claim passion for music and sound systems like this man lived. This guy was out of control passionate: NOT selling a component to a customer because he felt he wouldn't hear a difference and hand-selecting components for an event at Lyric with a singer to bring out the ambiance of the evening, and spending a MILLION DOLLARS to custom-design a room and physically isolate it from the effects of the NYC subway!?. That's the passion. These are good reads.

Where the Rubber Meets the Road Michael Kay of Lyric Hi-Fi & Video | Stereophile.com
Lyric HiFi & Video - Lyric HiFi & Video
Mike Kay 1923–2012 | Stereophile.com

I understand high end audiophiles quite well. I was one myself for a long time.

 

[fmw]

Check out this comment in the post here: Mike Kay 1923–2012 | Stereophile.com. Just great stuff, great passion:

As a junior member of a metro NY area rep firm, I got all the good jobs. One of them was taking Amanda McBroom around to see some of the retail establishments selling Sheffield Labs recordings. At the end of a long afternoon, Amanda and I ended up at Lyric and it was then that I learned what an incredible salesman Mike Kay was.
Knowing that Amanda was on her way to the store, Mike orchestrated a demonstration to end all demonstrations. The system he assembled included the Infinity IRS columns. The turntable, cartridge, and electronics? Ask someone else, I certainly don't remember. Nor do I have to. But I will never forget the incredible graciousness Mike showed to Amanda, his low-key but authoritative explanation of why he chose these components for the demo, why he wanted her to hear her voice singing her song "The Rose." Amanda's jaw dropped as the last notes faded.
I was transfixed. I heard nuances from those speakers I had never heard before. And I had played that song on many, many other systems, some of them world-class in their time.
It was my first introduction to the full force of "the Mike Kay difference" and it was then that I saw his contribution to our industry. I had just been exposed to the smoothest, most cosmopolitan presentation of technology in the service of music I could then imagine. Nothing I have seen or heard since has surpassed that afternoon.
Granted, Mike could be a real pain in the butt to a junior rep. (He had once told another manufacturer that I needn't call on the store because I couldn't do anything for him.) And I knew all the legends of his inviting the "unworthy" to leave his establishment.
But that afternoon, I saw genius. I know some will scoff at this description. To them, I say only "You weren't there."

What you encountered was a great pair speakers in an acoustically excellent room. The rest, I'm afraid, was arrogance and salesmanship. I'm a veteran of several years of bias controlled listening tests so the old high end audiophilia doesn't impress me any longer. I understand the passion and all that. I had myself once. The bias is very human and common to all of us. It is a matter of how we deal with it.

 

[mtrycrafts]

...and the Marantz has a slightly more collapsed and flatter soundstage. ...

Well, I have yet to see a controlled test to show these differences between components.

 

[PENG]

I agree.

But as you say, some people think their personal experiences are absolute - that if you don't agree with their own personal "findings", then you must be doing something wrong!

Because they can't be wrong!

Right on my friend!!

 

[PENG]

I throw my hat into the differences arena. For sure, I've heard it in an A/B comparison with some receivers I was testing out. I've heard it with an A/B of three receivers at a dealer and I've also heard it at my house. I have an old NAD integrated and also a 10 year old Marantz receiver. The NAD, rated at 1/2 the power of the Marantz, sounds better. It's absolutely not night and day, but there is a difference. The NAD somehow sounds a bit smoother, more liquid, more natural and the Marantz has a slightly more collapsed and flatter soundstage. I concede that I'm talking about a larger system chain with a receiver and integrated as opposed to just an amp.

Did you compare them in Pure Direct with no sub? If you did then Placebo works well on you imho. If you didn't, then surely they could/would sound different.

 

[krabapple]

No thanks.

Well, you should at least spell his name right in the article: it's Tom Nousaine, (as mtrycraft wrote), not 'Nosaine'.

Also you might want to cite/discuss another famous article on 'amp sound', by E. Brad Meyer

The Amp/Speaker Interface: Are Your Loudspeakers Turning Your Amplifier into a Tone Control?" E. Brad Meyer, Stereo Review, June 1991, page 54,

The Amp/Speaker Interface | Sound and Vision Magazine

My take: if one or both of the amps in your comparison is driven to clipping, or if the test is not double-blinded (either literally, or effectively via ABX switching) , randomized, level-matched to within 0.2 dB (at, say, 1 kHz at least), or lacks sufficient trials (16 would be a good target) then the test is seriously flawed. Ideally also the subjects should be trained with a series of differences that go from large to small.

 

[krabapple]

It is good enough, people like to abuse the term DBT in the audio industry, especially some manufacturers. Almost nobody does DBT's for audio and they certainly don't follow the strict protocol established by the medical industry.

The protocol for audio DBT isn't set by the medical industry. It's more properly a branch of sensory testing. There are books on this stuff --

http://books.google.com/books?id=XX9xwk9G0EUC

The ITU (International Telecommunication Union) also has issued elaborate (and double blind) protocols for evaluating relative quality of *real* audio differences, the most famous of which is probably
RECOMMENDATION ITU-R BS.1116-1*
METHODS FOR THE SUBJECTIVE ASSESSMENT OF SMALL IMPAIRMENTS
IN AUDIO SYSTEMS INCLUDING MULTICHANNEL SOUND SYSTEMS
http://www.itu.int/dms_pubrec/itu-r/rec/bs/R-REC-BS.1116-1-199710-I!!PDF-E.pdf



You could also consult a group that's done a lot of 'publishing' on audio blind tests

Links to blind listening tests - Hydrogenaudio Forums

What is a blind ABX test ? - Hydrogenaudio Forums