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Is there a noticeably audible difference between two level matched solid state amps under controlled

  • Yes... I believe a notable difference can be heard.

    Votes: 136 48.6%
  • No... I do not believe there is any audibly significant difference.

    Votes: 144 51.4%

  • Total voters
    280
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Excellent idea. I was going to scrap it, but makes a great deal more sense.
JJ
 

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I therefore conclude that not amplifiers sound the same nor do they sound the same in the same brand.
I don't think the premise was that all amplifiers sound the same - rather, that any two amps that measure the same, under the same measurement conditions, should sound the same. I.e. there isn't some other ethereal / unmeasurable property that gives amps "character".
 

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Hey all - been awhile since I posted up. Been busy moving and changing jobs and whatnot.

I'm glad this question came up. In my opinion it's actually very interesting. Similar to the typical can you tell cable differences/equipment (physical) grounding, and all the other jazz.

I initially tried to write my dissertation on this same question although my methodology was actually going to be scientific rather than survey, listening tests, etc.. There are ways of measuring differences in the auditory system in the brain and are done very regularly using electrophysiologic tests. They can measure differences early on or late in the system depending on where you want to look in the process.

I think it'd be really cool for an equipment manufacturer or one of the stereo magazines to sponsor something like this. It would provide really interesting information and actually scientifically ground some of these often debated questions.

-D
 

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This is very interesting topic and one that stirs a lot of debate. I have never attempted blind testing two amplifiers but I would find it really interesting to do a blind test between a valve and solid state amp.

Matt
 

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Yes, I can hear differences between amplifiers. I characterize those differences in clear terms like distortion or response time (i.e. not just warm or detailed). The simple set of measurements usually provided with audio gear is insufficient; a larger set of measurements is better but often not done or at least not published. The audible differences I have clearly identified in my own testing are differences that I believe can be measured, and I have some expectation of what those measurements would look like.
 

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I went from an Onkyo 905 AVR to a pre/pro set up and the amps inside the Onkyo were very good, it was only when playing at very loud levels that I could tell the difference, the Onkyo strained and the sound hardened and became a little too uncomfortable to listen where as the Rotel 1575 did not when pushed harder and was easier on the ear.
 

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This is an interesting discussion.

I do think it is very hard to tell a difference in amps unless you can do a comparison at home at the SAME TIME. I once did a comparison of 6 or more different amps I had in my rack at one time with the help of a friend. 3 of them sounded very similar and we had to nit pick which we liked better, 2 others had the same dry quality to the sound which made them sound dull to me and 1 was horrible compared to the others. These were all high end names from Classe, Aragon, Krell, EAD, ADA, Parasound and Sunfire. I had my list of favorites which differed from my friends list but the similar sounding ones were all in the top 3 on both our lists.

I think a great amp is just that, it should not add anything but what is on the recording. An amp can only damage the signal so the better ones just have less flaws IMO.

I have tried a lot of amps over the years and even some which are HIGHLY regarded which I hated. I am now back to the amp that does the least damage in my system which I regretfully sold but found again.

I am pretty much saying that in my system my amp does the least damage to the signal than all the others I have tried.
 

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I agree with draudio that we need to address the question scientifically. Now many on the purely objectivist side will say that this has been done. In my opinion it has not been done from a truly objective and scientific perspective. We know a lot about reproducing sound, a lot about how amps work, and a lot about the psychological and physiological aspects of perception. What we have not done is addressed in a systematic manner the reasons that people hear what they do. While the vast majority of differences of many types can be explained by placebo, expectation bias, and other "soft" variables, there are also some clear possibilities for differences to exist in the hardware.

The question that we need to address is why people hear what they do, searching for explanations systematically. This involves more than just showing no difference in ability to identify amps in ABX blind testing. There are so many variables that this does not explain that the results are simply not that interesting. For instance, a constant theme in many of the more reasonable comments here is that amps have to be operating within their nominal range to assume little or no difference. Many years of experience have demonstrated to me that this is often not the case when people do experience differences. What are the parameters that matter? How do we identify them in the field with such high variability in loads, source material, and system design? How should we test amps to reflect more closely how they will be used? What parameters matter most when dancing around this assumption that amps are operating within their range of ability? How do we identify differences that might exist? What is there that matters beyond obvious clipping, THD, IM, and noise? All of these are good questions that have only been barely touched as far as reasearch and reporting goes.
 

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key words...operated within limits, not clipping.

I'd bet almost any money people clip their amps far far more than they ever realise.

Then you can tell a difference between a valve and ss amp. but only because it is clipping.
 

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Elite Shackster , HTS Moderator Emeritus
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Leonard, you bring up a good point about not knowing everything about the perception of sound.

Used to be that everyone said humans could only hear to 22kHz or so, so amps and speakers just cut off at that point (or thereabouts) without much worry. I read an article about harmonics a few years back that studied how we can hear detail up to 44kHz, even though we can't hear a pure sinewave tone at that frequency. It has to do with the transient response and how more transient (step function) waves are more like a summation of a fundamental + many harmonics. The more harmonics that are added in, the "crisper" the edge of the waveform. Mathematically, this is known as a Fourier series.

But if the amps and speakers can't reproduce those frequencies, the sharp edge of that square wave (or plucking guitar string, or drum hit) gets rounded and the transient response is altered somewhat.

So how we perceive this, how transient and high frequency response is affected by distortion, etc, etc, is still not fully characterized.

That all being said, if the amps measure EXACTLY the same, then you wouldn't be able to tell the difference -- I just don't think that's possible yet.
 

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Elite Shackster
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What an interesting subject, and debate!

Over the years Ive found it pretty much impossible to distinguish the difference between 2 similarly spec'd amps, and not been all that sure about the differences between quite differently priced amps. Maybe its just my listening levels, not sure, but I'm quite happy to settle on that result personally. I'm fairly happy with my Onkyo and its amps do a perfectly fine job for my speakers. I would upgrade it once I have speakers that might benefit, but I would go silly.

I certainly think money is better pushed on speakers you like, then simply put n amp with it that will drive them well. As recruit has pointed out, I think the more important area is the processing etc, especially in HT setups, and more so in HT setups that need to double a the main music system as well.
 

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We know a lot about reproducing sound, a lot about how amps work, and a lot about the psychological and physiological aspects of perception. What we have not done is addressed in a systematic manner the reasons that people hear what they do.
Actually: We've concretely established that people hear exactly the same thing because two properly built and not-overdriven amps are identical in output to a specificity higher than human hearing.

While the vast majority of differences of many types can be explained by placebo, expectation bias, and other "soft" variables, there are also some clear possibilities for differences to exist in the hardware.
Which, on properly built amps not driven to clipping have been clearly eliminated time and time again by blind comparisons.

Read more: Can we really hear a difference between amps? - Page 3 - Home Theater Forum and Systems - HomeTheaterShack.com
No. We cannot. Unless at least one amp is being over-driven or is improperly built (adds coloration). That's been proven time and time again by testing.
 

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Discussion Starter #33
Do you know of specific tests that have been done that are recorded on the web... maybe links to them or maybe we can copy and paste a few of them here for added discussion.

It seems evident that there are indeed tests that have proven there is no difference, but I have never seen any tests that show there is a difference... and I suspect there are none, but more tests would be interesting to read.
 

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I am not sure if we are talking about just home audio and pro amps? I have definitely noticed a difference in amps before when speaking of car audio (I have had a slew of car audio amps). The only difference that was clearly audible was when I was running Linear Power brand amps. The sounds was (without sounding like a fan-boy) all those cliche attributes. The bass esp. was extremely articulate. I have used and currently do amps that are way more powerful, but dont have the same quality of bass at any volume level. I never believed there was honestly a real world difference before, nor have I experienced one since. LP amps use TO-3's, and have a relatively high damping factor, is this the difference...I dont know. I still have one of the LP amps in a closet for a rainy day (2502 IQ).
 

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I am not sure if we are talking about just home audio and pro amps? I have definitely noticed a difference in amps before when speaking of car audio (I have had a slew of car audio amps). The only difference that was clearly audible was when I was running Linear Power brand amps. The sounds was (without sounding like a fan-boy) all those cliche attributes. The bass esp. was extremely articulate.
There are several options.
1) It's imagined. Let's just assume it's not imagined because we'd need a DBT to determine if it was.
2) The other amps are underpowered (please remember that blatant lies regarding power are rife in the audio amp world). Realistically, a very good car amp might be 25WPC.
3) There's EQ occuring in the amp you like.
 

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There are several options.
1) It's imagined. Let's just assume it's not imagined because we'd need a DBT to determine if it was.
2) The other amps are underpowered (please remember that blatant lies regarding power are rife in the audio amp world). Realistically, a very good car amp might be 25WPC.
3) There's EQ occuring in the amp you like.

((The other amps are underpowered))

((There's EQ occuring in the amp you like))

These are possibilities....and I know Rockford Fosgate for sure adds like 2-3 db boost in their amps, or at least did in the past (so other companies might as well).

I run an amp in my car now that is wayyyyyyy more powerful than the LP though and while is gets extremely loud it doesnt have the best sq. 600 rms rated LP...and 4k rms measured and ratedfor the Autotek MM4000.1

I honestly did run different sub(s) on the Autotek as I dont own the subs That were played on the LP amp anymore. I mention the Autotek because this is the most powerful amp I have ever owned and can say for sure now that the LP didnt sound better as a result of more power. I did run those subs on several amps although and sounded the same with the one exception.
Other amps run...Alpine, Autotek, Rockford Fosgate, Sound Stream, Infinity, Clairion, Zapco, Polk Audio, The Hott Setup, Jensen, Optimus, Sony, Pioneer, MMats, Precision Power.....and others as well. Other than one is louder than another never really a memorable difference in sound. Some were very very reliable some not some run cool some hot...But same basic sound.
 

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Is it not the desire of the audiophile to have electronic equipment which does not alter the sound?

Your thoughts and comments will be interesting.
LOL Sonnie, the Zipser test is my fave example of the DBT working correctly. I also agree that the gear ideally will impart no signature at all on the signal passing through it, unless it is meant to, eg EQ.

My current position, based upon many years of designing, building, modifying and servicing a lot of amplifiers of probably every type is that there should be no audible differences between well made units, operating within their specifications. If there is, the unit was not designed well or the perceived colouration intentional on the part of the designer.

As I am not much of a fetishist over brands, I simply want to know if it will perform as I need it to reliably. Many years ago however, I spent a lot of time even testing parts in the amps I designed; would brand A resistor/cap sound better than brand B in this position or that and I tried many permutations of parts as well as topologies. It was not unusual to have as many as a dozen stereo amplifiers on my floor at one time. Because I changed them in/out so often I made a standard connector arrangement for them all so it was one step to change between them. One night after many hours I'd done the last bit of testing and thought I'd made the best amp so far, left it on to soak and went to bed. Next day I listened to some music over breakfast, then went to turn off the 'best' amp to permanently solder in some parts; the music kept playing. I had mistakenly connected in my old mule amp a modest SS Rotel, not the great tube amp I thought I had been listening to for the last couple of hours before bed.

After that I did a lot of testing by close level matching and switching to test myself. Amazingly obvious differences were suddenly not something I'd bet a dollar on. To be sure it wasn't my hearing, I tested others who were sure they could tell differences between just about everything. No one picked such things as a 30yo SS Marantz integrated over a Fisher tube amp for example (I had very efficient speakers with an even Z curve so no real issues there). There were many others too, so it reinforced to me how much our visual perception and preconceived ideas play in what we think we hear.
 
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