# Do Amplifiers "color" sound?



## Todd Anderson (Jul 24, 2009)

I'm sure this is a question that a lot of us have asked... I believe that this was touched on in the top 10 myths link that was posted years ago.

Anyhow... this is an interesting read... the short end: in double-blind testing of several hundred people, the ability to hear a difference between amps (even discern between a $6000 amp and a $200 AVR) was essentially a coin flip. In other words, no better than a guess.

the article


----------



## Anthony (Oct 5, 2006)

The only problem I have with their methodology was that the participants were "guessing" which amp was which. A better methodology would be for people to rate or describe the sound of each without knowing which was which.

Another area they did not test was how well the amps performed over a broad range of listening levels or dynamic range. Some amps can sound great but be forced into distortion quicker than you'd expect or don't quite "pop" when the source should be getting loud.

That all being said, I doubt the results would have been that different. Amps have come a long way since the 70's and 80's when the super high feedback designs (the Japanese amp sound) produced power and low THD numbers at the expense of a shrill sound. Most modern amps I would expect to have a pretty flat frequency response over the audible range. The main difference among them being build quality, possibly power supply noise (I've heard good cheap amps that had horrible capacitor hum that drove me nuts), and power handling, especially for difficult speakers (like 4 Ohm loads, capacitive loads, low efficiency, etc).

Of course my favorite study like that was one that had people drink the same glass of wine twice and were told one was cheap and the other expensive. Most reviewers noted how much better the expensive wine was. I don't remember if the researchers told them they were the same at the end


----------



## Jungle Jack (Jul 28, 2009)

Hello,
This is something we have brought up many times and I have also linked to Richard Clark's $10,000 Amplifier Challenge as well. I am not familiar with the website you linked to and I am somewhat concerned about its design.
Cheers,
JJ


----------



## GoNoles (Jul 7, 2012)

When I swapped from a 2007 Onkyo to 2009 Denon, I noticed a slight difference.


----------



## pharoah (Jul 21, 2012)

i know there have been several arguments about this over the years.julian hersch <(possibly misspelled)who wrote for the magazine stereo review.made a comment about amplifiers all sound the same.which stirred up much controversy.then folks of the other side say they do sound different.i can tell a difference in the 2 amps i currently own.1 is a home built t-amp,and the other is a nad c326bee.i think the nad has a bit better detail.its not by much mind you.


----------



## tonyvdb (Sep 5, 2007)

The problem with the so called "Color of the sound" is more an issue of the implementation of the room correction and even the slight variances in positioning the mic.
If an amp is designed correctly there should be little to no difference in the sound. 
Another factor is distortion, if your running an amp to its max output (and that is not necessarily what the level meters say) A power supply or even the power from the outlet can also be a contributing factor.


----------



## RBTO (Jan 27, 2010)

Most amplifiers whether low cost or more expensive, have had flat frequency and phase responses for some years now. The only other thing which can color an amplifier's output is distortion (harmonic, intermodulation and transient-intermodulation - the latter having been addressed in most modern designs).

Harmonic distortion isn't as distasteful as intermodulation distortion, since we hear a lot of harmonic distortion in every day life. However, in most recent amplifier designs, both of those have been driven to very low levels so the main source of system distortion remains to be the microphone (little control over that), and speakers.

That being said, the distortion of the speakers is much greater than low cost or expensive amplifiers and hence, the amplifiers will sound very similar. Where higher cost amplifiers have the advantage is they are usually built to higher standards (physically and electronics-wise) and have better components which will fail less often, so they will endure much more usage and ultimately last longer (generally speaking). Sound-wise, it probably is a toss-up nowadays when many lower cost amplifiers are compared to their Hampton cousins. Coloration has all but disappeared (except when it's purposely introduced).


----------



## andy_c (Aug 8, 2006)

A PDF file of the original amplifier listening test article can be found here.


----------



## Todd Anderson (Jul 24, 2009)

Interesting responses!

I don't have a horse in this game... Just thought it was interesting. I guess I tend to believe that the design is well thought-out, knowing how obsessive academic types/stats-geeks are about study designs. In many ways, the fact that telling a difference in a double fashion proved to be a toss-up is really interesting.

Of course, I don't think this down plays a well made product. 

@RBTO: I enjoyed reading your take - thanks! ;-)


----------



## soundoff (Oct 3, 2007)

My first stereo was my parents, a tube powered record player. Speakers were housed in solid wood frames and were built like cabinets 4' tall 24" W 24"D. Anyway, when I got older and bought my first reciever built with solid state components I could say there was a different "color" to the sound (ignoring room modes and difference in speakers)


----------



## nova (Apr 30, 2006)

I suppose I have a rather simplified view of this issue. In my limited experience with various amps I believe tube amps do color the sound a bit. As for solid state amps I don't think there is a difference with one caveat; insufficient power. Again, in my limited experience I have found that my speakers sound better with a good amp. I don't think the amp colors the sound, I think the amp is better able to control the speakers resulting in (choose your favorite term) cleaner, crisper, tighter, tonal articulation, depth, detail, richer, etc. sound.


----------



## JBrax (Oct 13, 2011)

^^^ +1


----------



## yoda13 (Feb 14, 2012)

nova said:


> I suppose I have a rather simplified view of this issue. In my limited experience with various amps I believe tube amps do color the sound a bit. As for solid state amps I don't think there is a difference with one caveat; insufficient power. Again, in my limited experience I have found that my speakers sound better with a good amp. I don't think the amp colors the sound, I think the amp is better able to control the speakers resulting in (choose your favorite term) cleaner, crisper, tighter, tonal articulation, depth, detail, richer, etc. sound.


These few sentences pretty much sums up the way I see it. The room your in, your speakers and applied DSPs are more than likely to "taint" the sound providing your amp is running within specs. In other words, it's the delivery of the source to your ears that impact the sound, not the amplification of the source.

This is for solid state amps. I can't comment on tube amp as I have very limited personal experience with it.

cheers


----------



## bluemax_1 (Feb 14, 2011)

The answer to the thread title is not simple, as the answer can be appropriately Yes, and No under various conditions.

I've read a lot of articles as well as studies about acoustics and how the various components intermingle with each other.

First off, let's begin with the now famous Richard Clark amp challenge. Specifically with properly designed solid state amps, level-matched and driven within their design/power output specifications, with commonly available modern design speakers, the answer is no, which is why no one has beaten the challenge. Yes, different amps will have differing dynamic capabilities. A 1000 watt monoblock is going to be able to reproduce greater volume and dynamics without distortion (IF the speakers used can handle that kind of power) vs. a 75 watt avr channel. Try driving some 4 ohm, 83db speakers loud with either option and the difference is easily heard, but as the challenge stands, level-matched and within its designed operating parameters, they'll sound too similar to differentiate.

That said though, there's an interesting article online (perhaps someone with better Google-fu can dig it up) on another amp challenge with Bob Carver. He claimed that he could take one of his $100 (I think it was $100, or some fairly low price) amps and make it sound indistinguishable from any particular audiophile amp a select panel of reviewers for a magazine chose as the 'Reference' challenge amp. IIRC, there was also a time limit involved, of 2-3 days.

The panel selected an amp, which was one of the more highly regarded amps available at the time. The panel of reviewing skeptics also admitted to attempting to bias the challenge by deliberately selecting a tube amp not only because it was highly regarded, but also specifically because its architecture and design was as different as possible to the solid state amp Bob was proposing to replicate the sound with.

They proceeded to a/b the amps with the same speakers. The initial verdict was that yes, all the listeners (including Bob himself) acknowledged that the amps were easily distinguishable from each other even when blinded, and Bob even admitted that some of the audible differences of the challenge amp (which of course, cost multiple times what Bob's amp cost) were actually desirable and pleasing.

He then set about analyzing the challenge amp and in particular, comparing the input vs output signals of said amp with an oscilloscope and waveform analyzer among other things, and then set about modifying his own amp in his hotel room with the boxes of parts and equipment he had brought along. After a day or two, he called the review panel back for another comparison, at which time, they concluded (Bob as well), that although the 2 amps now sounded very much alike, that there were still some small differences that made them distinguishable from each other. So Bob went back to measuring and modifying.

One day after the time limit, he called the reviewing skeptics (now, not so skeptical) back for another comparison, and this time, dumbfounded, they all concluded that none of them could distinguish one amp from the other. They concluded that although it was slightly outside the timeframe agreed upon, that Bob had won the challenge by being able to mod his much cheaper amp to sound identical to the 'Reference' challenge amp costing many times more. Bob then explained that it was simply a matter of measuring the distortions produced by the 'Reference' amp, and knowing the design of his own amp inside and out, figuring out how to replicate these 'pleasing distortions'.

I don't recall the amp manufacturerz and model numbers, but in an update to the online article, the writer amended that since quite a few years had elapsed since the challenge, they decided to reveal the identity of the 'Reference' amp.

In this case the answer is Yes, an amp CAN color the sound, and the distortions it produces can actually be preferred by listeners.

The last case is an interesting one that I was completely unawares of till I actually heard the difference myself. A friend of mine likes collecting speakers, and in response to the "all amps sound the same" claim regurgitated by yours truly, proceeded to demo an old pair of speakers with an acoustic recording on vinyl, first with some old amp (unfortunately not having yet become z full blown a/v nut, I don't remember ANY of the brands involved), then with a solid state amp. The solid state amp sounded awful and lifeless.

He then showed me a printed article on the evolution of amps with the advent of solid state architecture, and... the resultant evolution of speakers which was influenced by the evolution of amp design (and the resultant evolution of pop music, influenced by the evolution of the amps and speakers). The article detailed that earlier speaker designs were built to mate well with pre-solid state era amplification. One of the common traits was that these amps tended to have low output wattage and low damping factors and as such, the speakers had to be easy to drive, and the drivers were built differently because the damping factor was not used to control the drivers.

When solid state amps first emerged, they tended to have damping factors orders of magnitude greater. This in turn allowed speaker designers and companies building drivers to develop drivers that could play louder and handle more power, but also dependent on those high damping factors to control them. He then explained that mismatching the types of amps with the wrong types of speaker designs both sounded awful, but in different ways.

He then demo'ed 2 sets of speakers, the old pair with the old tube amp and then with the newer solid state amp. The older speakers sounded great with the old tube amp, but sounded dead with the solid state amp. He claimed that the reason for this was that the old speakers were designed to be easy to drive and the drivers were more controlled without needing the higher damping factors. Pairing a solid state amp with them resulted in overdamping the drivers, and the result was relatively dead sounding.

He then hooked up the newer speakers to the same amps and turntable and this time, the old amp made the speakers sound anemic and flabby, where the solid state amp sounded great.

I still don't fully understand the recriminations of that demo, but the amps definitely sounded different on the different speakers.


Max


----------



## MagnusAtom (Oct 23, 2012)

bluemax_1 said:


> The answer to the thread title is not simple, as the answer can be appropriately Yes, and No under various conditions.
> 
> I've read a lot of articles as well as studies about acoustics and how the various components intermingle with each other.
> 
> ...


Cool story.


----------



## JerryLove (Dec 5, 2009)

All properly built amps which are not being over driven will sound the same (the waveform out will look just like the waveform in only bigger). Since the amps we are discussing are intended for *reproduction* (as opposed to a guitar amp, which is intended for production); that is what it is supposed to be.

Some people like the effect of clipping on a tube amp; and so run tube amp or pre-amp stages above what the tube can flatly render. This does color the sound (as all overdriving does)


----------



## MagnusAtom (Oct 23, 2012)

Amps have different sounds. The goal is to find one that has the highest level of fidelity. One way is to do a recording for yourself in the best possible manner, and have that replicated with the same speakers that you adjusted the recordings with. A good amp in a good system should be quieter than the system you use in your recording. Tone is something that must remain constant. Classical guitars are one easy subjects to compare tonality of amps with. A lot of SS amps I've heard on a reference recording changes the tone of the full value of the nylon tones- I've only tried them on high end amps. Be sure to play the amps in the same volume. Spl meters with pink noise is an easy reference to the difference in gain from 2 different amps. U can run a mic from the output of your system, change the amp and you should then see a difference already. Also, if you look into two amps of two brands, the varying parts with different brands and values will also contribute to the sonic differences. 

Good amps should have accurate tonality, for it is the most fundamental criteria to listen to music with. 

Outside from the high fidelity sphere, you may just choose to "enjoy" the sound-which most people loosely term it "hi-fi". 

The real question then is... What are you listening for?


----------



## lcaillo (May 2, 2006)

A very good point. Most people hear exactly what they are listening for, or expecting to hear or not hear. 

While I agree that there are differences among amps, I believe that they are smaller than in the past and far less than many would suggest. I would like to see some better definitions of terms like "accurate tonality." How do you assess that?


----------



## JerryLove (Dec 5, 2009)

MagnusAtom said:


> Amps have different sounds.


 Then here's how you can make an easy $10,000: http://tom-morrow-land.com/tests/ampchall/index.htm

Funny. Hundreds of people tried. No one managed to hear these differences in amps not over-driven.


----------



## yoda13 (Feb 14, 2012)

Seeing that some ppl suggest that amps running within their specs will "color" the original source material, I wonder what manufacturer's would say if one was to ask them if they purposely designed their amps to alter the source material?


----------



## chashint (Jan 12, 2011)

yoda13 said:


> Seeing that some ppl suggest that amps running within their specs will "color" the original source material, I wonder what manufacturer's would say if one was to ask them if they purposely designed their amps to alter the source material?


The specs on modern amps (and AVRs) for THD nominally being <.1% and frequency response often being +/-<1dB from 10HZ to >50kHZ suggests the answer to this is a resounding no.


----------



## Wardsweb (Apr 2, 2010)

From my experience, amps can, but not always, have a signature sound. McIntosh comes to mind, it is different than a Pass Labs, in turn different from the SST Ampzilla 2000. That and I haven't even talked about tubes. SET amps being very different from Push-Pull. Throw in Pentode, Triode, and we still have to talk about topology. So, for me they can sound different. 

This becomes very apparent when trying to get the synergy right in a system. An amp can compliment a speaker or it can make it unlistenable. Case in point, a speaker with a shrill high end can be tamed by a tube amp but the same amp can make a flat response speaker seem dull. 

Now all of this has to be taken from your point of view and how you hear it and want to hear it. Some people like highs and some perfer more bass. Some will notice a substantial difference and others more of a nuance. There is no black or white but shades of grey.


----------



## JerryLove (Dec 5, 2009)

The only spot I've noticed a difference between my McIntosh and Yammy Pro amps was on the B&W 801N, which spends a lot of time at 2ohms (where the Yammy doesn't really want to go).

I've noticed the difference between my Yammy and Marantz AVR's amp on more speakers than that; but again always on the hungry and/or low-resistance gear (hear it on the 801 MatrixII, but not on the PSB 400i).

Don't know if someone is still doing it: but there was a $10k challenge to anyone that could tell the difference between level-matched amps not driven into overload. Hundreds tried (at least one sponsor used to take the challenge to trade shows) but none won.

There are a lot of differences in amps; but a difference in sound between well constructed amps running (not overloaded) a speaker they are sufficient to run is not one of them.


----------



## MagnusAtom (Oct 23, 2012)

JerryLove said:


> Then here's how you can make an easy $10,000: http://tom-morrow-land.com/tests/ampchall/index.htm
> 
> Funny. Hundreds of people tried. No one managed to hear these differences in amps not over-driven.


Me, and a number of folks here might just be the outstanding ones with gifted ears then! 

I don't mind having a look at the registration form. ")


----------



## MagnusAtom (Oct 23, 2012)

Wardsweb said:


> From my experience, amps can, but not always, have a signature sound. McIntosh comes to mind, it is different than a Pass Labs, in turn different from the SST Ampzilla 2000. That and I haven't even talked about tubes. SET amps being very different from Push-Pull. Throw in Pentode, Triode, and we still have to talk about topology. So, for me they can sound different.
> 
> This becomes very apparent when trying to get the synergy right in a system. An amp can compliment a speaker or it can make it unlistenable. Case in point, a speaker with a shrill high end can be tamed by a tube amp but the same amp can make a flat response speaker seem dull.
> 
> Now all of this has to be taken from your point of view and how you hear it and want to hear it. Some people like highs and some perfer more bass. Some will notice a substantial difference and others more of a nuance. There is no black or white but shades of grey.


+1


----------



## ericzim (Jun 24, 2012)

JerryLove said:


> All properly built amps which are not being over driven will sound the same (the waveform out will look just like the waveform in only bigger). Since the amps we are discussing are intended for *reproduction* (as opposed to a guitar amp, which is intended for production); that is what it is supposed to be.
> 
> Some people like the effect of clipping on a tube amp; and so run tube amp or pre-amp stages above what the tube can flatly render. This does color the sound (as all overdriving does)


+1 Jerry hit the nail on the head.


----------



## MagnusAtom (Oct 23, 2012)

I think in the real world, we have different habits of listening- I don't think anyone listens to music within a limited spl range.


----------



## JerryLove (Dec 5, 2009)

MagnusAtom said:


> I think in the real world, we have different habits of listening- I don't think anyone listens to music within a limited spl range.


 I always listen to music in the range between 0db and 200db. In fact: I'd say I listen with an even more limited SPL than that, but I can say with surety between 0db and 200db.


----------



## robbo266317 (Sep 22, 2008)

JerryLove said:


> I always listen to music in the range between 0db and 200db. In fact: I'd say I listen with an even more limited SPL than that, but I can say with surety between 0db and 200db.


:rofl::rofl::rofl: 

I like your thinking :T


----------



## MagnusAtom (Oct 23, 2012)

So when you reach 100db, do you still think all amplifiers sound the same?


----------



## lcaillo (May 2, 2006)

100 dB would be very different under different conditions. Driving K-horns to that level and driving B&Ws to that level would likely have very different results, causing some amps to exceed their design limits and others not. We have to be careful about defining such conditions for the discussion to be meaningful.


----------



## JerryLove (Dec 5, 2009)

MagnusAtom said:


> So when you reach 100db, do you still think all amplifiers sound the same?


 If the amplifier is not being over-driven then, "yes".

If the amplifier is clipping, or if the power-supply in the amp is underpowering it, or if the Ohm load-drop is too much for the ability to put out current, then "no".

I've been in both. I've had to buy amps to resolve sound problems. In all cases: I can reasonably point to the load being too much. (for example: In all cases, where the weaker amp was not having a problem, hooking up the more powerful amp made no difference at all in sound)

This is true regardless of SPL.


----------



## MagnusAtom (Oct 23, 2012)

Pointing the mic from my listening position shows different curves with different amplifiers, in the same room setting-there was an obvious difference in frequencies of more than 10db, and in listening to different softwares, other amps were more exciting, another was more laid back, and then another, smoother. At the same gain, another brand had heavier bass, and then highs. 

While hundreds may not have succeeded in the "all amplifiers sounding the same" challenge, hundreds of thousands can tell the difference. 

Now, I have a 50 watt amplifier built to the design of a known amplifier brand, and while it is easy to be biased towards your own labour, I got to say, the known brand was better sounding, with and without a semi 'blind' test. 

While I think some audiophile beliefs border on psychological, quite a number of amps I've tried are not, and probably not in your list of amps you've heard. Sorry, I just can't wrap my head around your approach, til I hear and know for a fact, like a measurement curve, or a well written white paper with reasonable and practical perimeters. 

Well, I guess we'll have to agree to disagree.


----------



## ericzim (Jun 24, 2012)

MagnusAtom said:


> Pointing the mic from my listening position shows different curves with different amplifiers, in the same room setting-there was an obvious difference in frequencies of more than 10db, and in listening to different softwares, other amps were more exciting, another was more laid back, and then another, smoother. At the same gain, another brand had heavier bass, and then highs.
> 
> While hundreds may not have succeeded in the "all amplifiers sounding the same" challenge, hundreds of thousands can tell the difference.
> 
> ...


Different amplifiers with different pre-amplifiers or are they seperates?


----------



## AudiocRaver (Jun 6, 2012)

I'm going to add another voice of agreement with JerryLove on the topic, that different amplifiers operating within their linear ranges are going to sound the same. Then I'll disagree just a tiny bit, knowing that there are a lot of ways to design an amplifier, and that subtler types of distortion, like Intermodulation Distortion (IM) and Transient Intermodulation Distortion (TIM), when they exist (not so often these days), can be overlooked in specs and tend to only be heard with certain types of program material. One listener might hear it in the "tang" of a cymbal while another is paying attention to the vocalist. With a well-powered system, though, as already stated, it seems highly unlikely that such artifacts are measurable or audible.

The human ear is a very sensitive instrument. Unfortunately, it is also an instrument easily influenced, even easily fooled.

AudiocRaver


----------



## JerryLove (Dec 5, 2009)

MagnusAtom said:


> Pointing the mic from my listening position shows different curves with different amplifiers, in the same room setting-there was an obvious difference in frequencies of more than 10db


Can you please post your FR charts and describe the setup?

I could actually run a similar test (though if amp performance differences showed up on objective tests: this would have been settled *long* ago (note the lack of "do speakers color sound" discussions)).

Put up what you've got and I'll try the same with my mic, PSB 400i's and a trio of amps. See if I can replicate your results.

Human hearing is "below average" in the mammal world, and then brain processing kicks in to fool you further. There're upper-atmo balloons which listen for the tell-tale sounds of a nuclear explosion from the opposite side of the world; there is sonar and RF gear that can image spaces passively from background signal. 

Let me know when you can walk into a room and, from ambient noise, describe the room to a resolution of a cm with even an active source (see bats), much less a passive one (see passive sonar array)


----------



## yoda13 (Feb 14, 2012)

AudiocRaver said:


> The human ear is a very sensitive instrument. Unfortunately, it is also an instrument easily influenced, even easily fooled.
> 
> AudiocRaver


:T there you go!


----------



## phreak (Aug 16, 2010)

AudiocRaver wrote:
The human ear is a very sensitive instrument. Unfortunately, it is also an instrument easily influenced, even easily fooled.


Best comment in the thread? Gets my vote.


----------



## bluemax_1 (Feb 14, 2011)

There seem to be two different sides of the discussion that aren't necessarily meeting in the middle.

1) Amps that are designed to replicate the input as accurately as possible (flat frequency response) AND working within their design limits sound the same with the same speakers

2( Different amps CAN sound different if:
a) one amp is working within its specs and the other is in distortion
b) one of the amps is (intentionally or otherwise) built with a 'house sound', i.e. a NON-FLAT frequency response. If you measure the input signal vs the output, these are easy to identify.

Personally, I prefer NOT to use amplifiers (or cables) as tone controls. I'd rather the amp not roll off the frequencies above 7-12kHz to make everything sound 'warm'. I'd prefer they not boost the 2kHz region slightly to make vocals sound more forward etc.

I would optimally prefer that the entire chain reproduce the recording as faithfully as possible, but as with any preferences, others may differ. Some prefer the types of distortions certain amps produce. IMO, a speaker that NEEDS a high frequency roll off to sound good is a flawed design. Likewise, a speaker that inherently and innately (due to its design and construction) rolls off the high end is also flawed. Both of those examples usually have some kind of odd behavior in the frequency response and/or off axis response.

If the amps play flat with minimal distortion and have enough power for what I'm using them for, that's good enough for me.


Max


----------



## gsmollin (Apr 25, 2006)

bluemax_1 said:


> There seem to be two different sides of the discussion that aren't necessarily meeting in the middle.
> 
> 1) Amps that are designed to replicate the input as accurately as possible (flat frequency response) AND working within their design limits sound the same with the same speakers
> 
> ...


Well said, Max. It is worth noting that Mr Clark qualifies the amplifiers he uses in the amplifier challenge. So if he finds a prospective test amplifier with enough distortion to be audible in the test, he won't use it in the amplifier challenge, since that would cost him. So this "challenge" is pretty bogus. It is precisely those amplifiers with peculiar responses, and including clipping or power supply overload that makes amps sound different. Virtually identical amplifiers running under identical conditions sound the same. Ho hum.


----------



## JerryLove (Dec 5, 2009)

gsmollin said:


> Well said, Max. It is worth noting that Mr Clark qualifies the amplifiers he uses in the amplifier challenge. So if he finds a prospective test amplifier with enough distortion to be audible in the test, he won't use it in the amplifier challenge, since that would cost him. So this "challenge" is pretty bogus. It is precisely those amplifiers with peculiar responses, and including clipping or power supply overload that makes amps sound different. Virtually identical amplifiers running under identical conditions sound the same. Ho hum.


 How does that make anything "bogus".

I don't think anyone has disputed that an amp which *deliberately* colors sound colors sound. 
No one has argued that amps which distort the output (for example: by running into clipping) color sound.

Properly built amps, running within their tolerances, do not color sound. 

You will not hear a difference between my Marantz, McIntosh, and Yamaha amps running my PSB 400i's at (say) 40w peak output.

That is the claim. That is what the challenge is to prove. That is what it does prove.


----------



## gsmollin (Apr 25, 2006)

JerryLove said:


> How does that make anything "bogus".
> 
> I don't think anyone has disputed that an amp which *deliberately* colors sound colors sound.
> No one has argued that amps which distort the output (for example: by running into clipping) color sound.
> ...


Who decides which amplifiers are "properly built"? Clark does. So if Joe Audiophile claims his amp colors the sound, and he can hear the difference, Clark checks it out ahead of time, and if it is true, he will not " challenge" the amp. That's the bogus part. For instance, I had a Pioneer amp that colored the sound. It would color the sound so bad, that certain sounds would make it trip off. Played just below this point, they were very audible. Clark would have disqualified this amp, or de-rated it to 10 watts to cover up its problems. But people who claim they hear differences are hearin these kinds of things. So Clark's claim, in fine print, is that amps that sound the same don' t sound different.


----------



## bluemax_1 (Feb 14, 2011)

gsmollin said:


> Who decides which amplifiers are "properly built"? Clark does. So if Joe Audiophile claims his amp colors the sound, and he can hear the difference, Clark checks it out ahead of time, and if it is true, he will not " challenge" the amp. That's the bogus part. For instance, I had a Pioneer amp that colored the sound. It would color the sound so bad, that certain sounds would make it trip off. Played just below this point, they were very audible. Clark would have disqualified this amp, or de-rated it to 10 watts to cover up its problems. But people who claim they hear differences are hearin these kinds of things. So Clark's claim, in fine print, is that amps that sound the same don' t sound different.


I don't think you're understanding the idea of the challenge properly. Sure I can take ANY amp in the world, no matter how expensive, place a capacitor across the output terminals inside the amp and ANYONE can hear the difference (the capacitor across the terminals will cut off the frequency spectrum depending on the capacitor).

The idea is that a properly made amp, working within its specifications should NOT be modifying/distorting the signal. An amp that DOES distort the signal is a poorly built amp (no matter how expensive, and despite the liberal use of gold, platinum and pixie dust). All properly built amps that DON'T modify the signal, and aren't driven past their limits into distortion sound the same, whether they cost $200 or $20,000.

The idea that an amp costing 20x more than another amp, would sound better or clearer 'as if a veil was lifted' (how many times have we read that silly line?) when both amps measure the same is simply ridiculous placebo effect/expectation bias. But yes, I can build an amp that cuts these frequencies or boosts those and claim that not all amps sound the same. So what? Is there a point to that? I could haul in an empty box with speaker terminals and claim that it's an amp and I can absolutely hear the difference between it and my $10,000 amp and I would. Isn't that the ultimate definition of a device that modifies and distorts the signal? It cuts ALL the frequencies it receives. The biggest possible difference from any other amp out there. But I wouldn't call it a properly built amp.

Who decides which amps are properly built? It isn't just a person with arbitrary requirements. We're talking simple, standards here. Basically, the amps that distort the signal the least, within certain tolerances for things like THD and all the other specifications that decent amp manufacturers provide.

Why do I use Emotiva XPA-1's to individually power the speakers in my HT? Simple, they measure right up there with some of the best for minimal distortion of the signal, and have the power requirements (plus headroom) to cleanly hit the SPLs I want at my listening distances with the speakers they're paired with AND they can do all this at a fraction of the price of most other amps with specs anywhere even close. , they measure better than amps costing multiples of their pricepoint.

The room is treated and my sound system is also calibrated to ensure that the frequency response is as even as possible. I don't particularly care WHAT might be causing a dip or peak in the frequency response (whether it's the room, the speakers, the amp, the cables or whatever), I want the delivery system to be as true to the recording as possible.


Max


----------



## jackfish (Dec 27, 2006)

Hmm, then I guess I am mistaken that a Pass Labs X250.5 sounds better in my system than my Emotiva UPA-1 monoblocks?


----------



## steve1616 (Apr 6, 2009)

Who knows if your mistaken. You would have to do a double blind test to confirm this. I think that what this whole study is trying to show is that you don't have to spend rediculous money to have the same sound as the guy that spent 100k on an amp. I have heard many differences in speakers, but any decent amp will sound the same as long as it isn't being pushed beyond its limits. I have seen some super expensive amps out long before some el cheapo's. It is sad how many lies have been spread through the audio industry to sell voodoo. Electricity in an amp is simple, but you wouldn't know it with all the lies spread about it. I have done many double blind tests, and it is sad how many owners can't tell the difference between their 20k monoblocks and their cheap receiver. Even after they prove it in the listening tests, they will still make excuses as to maybe their hearing being bad that day, and etc. It shows you how much marketing, lies, and illusions affect our buying preferences.


----------



## jackfish (Dec 27, 2006)

steve1616 said:


> Who knows if your mistaken.


Why would you say that, and then go on to imply that I have to be? The problem is objectivists declaring that subjectivists are wrong, that they cannot be hearing or experiencing what they are. I think that the Pass Labs X250.5 running in Class A sounds better than the Emotivas running in Class A/B. And I think there are observable/measurable reasons it does. Once past 15 peak watts then its likely all bets are off.


----------



## bluemax_1 (Feb 14, 2011)

jackfish said:


> Hmm, then I guess I am mistaken that a Pass Labs X250.5 sounds better in my system than my Emotiva UPA-1 monoblocks?


It's possible. I don't have any idea how the UPA-1 or X250.5 measure, OR how you're using them and what you have them connected to.

I DO know how the XPA-1 measures and I got it because of that, AND because I wanted at least 500 watts at 8 ohms and 1000 at 4 ohms to be able to hit THX Reference cleanly.

That said though, have you ever tried a true double blind test of the two? I've known several people who swore that they could hear a subtle but distinct difference who upon blind testing, discovered that they couldn't really tell the difference when they didn't know which was which.

One of the funniest accounts I'd ever read (and I can't even recall where I read it), was about this person performing a test of expectation bias in college. He set up his system with a 'switchbox' and told people that it was connected to 2 different components, an average and a high end component. They could audition the two by simply switching between them using the switchbox. In reality, all the box did was make a loud CLACK when the switch was flipped back and forth. The vast majority of folks commented on how the high end component sounded better, to varying degrees, some claiming it was a subtle difference, others that it was an obvious difference, even though they were listening to the exact same setup. Out of the numerous people he tested, he said only ONE person sat down, flipped the switch, CLACK. Flipped it again, CLACK. Looked at him and said, "Very funny" and walked out of the room. Everyone else claimed that they'd heard a difference.

Personally, I added the XPA-1s to my system after testifies the system powered by my Onkyo 5008. I have to say, the 5008 does a remarkable job on its own, but when I went from regular connections to bridged, I could hear a difference, but ONLY when listening above about -15db from calibrated THX Reference. I decided to try the XPA-1s to see how they would sound, and to me, they sounded identical, until I turned the volume up past about -5db from Reference. The built-in amps in the 5008 are incredibly good. Very low noise floor and quite flat, until they're pushed too far, as with any other amp.

I realized I had added the XPA-1s simply for clean headroom at THX Reference. One of these days, I'm going to get a Crown XLS2500 to see how THAT sounds (and measures) with the rest of my equipment. $899 per monoblock is a great price. $275 per channel is even better if the results are equal.


Max


----------



## JerryLove (Dec 5, 2009)

Exactly: If it's so different that you can tell minutes apart, then you should be able to tell second apart.

I was at an event last weekend where one of the vendors (Jim Salk) actually had a rapid-switching controller with the ability to level match. I drooled on that almost as much as his speakers as it makes ABX testing *so* easy. 

He used it to let people compare his gear. Serious Kudos.


----------



## steve1616 (Apr 6, 2009)

Jackfish, I didn't mean to imply that you were or weren't actually hearing a difference. I was merely stating that you really don't know whether you are hearing a difference unless someone helps you to do a double blind test with level matching the volume. I am not saying that all amps sound the same. Some people build amps on purpose that distort because they like the sound. 

I will state without a doubt that you can get great quality without spending a bunch of money. It is sad that some of the super high end amplifiers like certain tube amps distort the sound way more than certain el cheapo receivers. So the next question, if you can hear a difference, which one is correct. There is an audo magazine back in the day that did a good job of debunking all of the voodoo that most magazines sell. I will try to find the name of it because it was a truly good read that really shows how many lies the audio industry tries to sell.


----------



## 8086 (Aug 4, 2009)

Lower end amplifiers are more likely to color sound. As you go up to the higher end of the amplifier stratosphere, things begin to plateau and most higher end stuff will more or less sound about the same.


----------



## steve1616 (Apr 6, 2009)

Just curious, what do you consider high end?


----------



## jmschnur (May 31, 2011)

I suspect that the differences one hears have to do with they way an amp handles varying impendence loads presented by a particular speaker. This will affect damping factor and in some cases for some speakers and some amps lead to distortion (e.g impedance less than 0.1 ohms at one frequency and 7 ohms at another.)


----------



## steve1616 (Apr 6, 2009)

I agree with you about the impedance rating, but there are some very reasonable receivers that will even handle the impedance loads of very demanding speakers. The SVS MTS-02s are very low impedance loads but in their defense are truly not that hard to drive. I have a sunfire that drives them great, but my brothers $450 Onkyo receiver drives them just as good at the highest levels he listens to. I could not hear the difference in a double blind test.


----------



## jmschnur (May 31, 2011)

steve1616 said:


> I agree with you about the impedance rating, but there are some very reasonable receivers that will even handle the impedance loads of very demanding speakers. The SVS MTS-02s are very low impedance loads but in their defense are truly not that hard to drive. I have a sunfire that drives them great, but my brothers $450 Onkyo receiver drives them just as good at the highest levels he listens to. I could not hear the difference in a double blind test.


Try driving an electrostat at high volumes at high frequencies with an onkyo receiver.

I did not all amps had problems nor did I say all speakers. I said a reason for possible coloration was the impedence of the speaker can affect some amps.


----------



## GranteedEV (Aug 8, 2010)

Do amplifiers change the sound produced by the speaker? Sure. They may put the sound through a phase shift, they may add low level distortions that are level dependant and possibly even rise at low SPLs. They may interact differently with varying phase angles. 

Do amplifiers audibly affect the sound heard by the listener? I think if you're hearing such differences between good amplifiers, your room is too dead, which is IMO not a good thing for stereo (perhaps a pro for multichannel though). In a moderately live room such things will be masked. 

I always suggest that people focus on the first 95% first - the room and speakers. Getting those two things right SHOULD be more expensive and time consuming than finding what you presume is your favorite amplifier, preamplifier, DAC, CD Player, etc.


----------



## steve1616 (Apr 6, 2009)

jmschnur, I was just giving an example. There are so many different scenarios. Everyone keeps missing the point. Also, the electrostats might be fine on an onkyo. It depends more on the sound levels you want to run. There are some high end tubes that would be fried just as easily pushing high loads as a cheap onkyo. Do you not understand that I am trying to say that price does not determine the amps capability. 

GuaranteedEv seems to have my same thought process. The amp is little compared to the speakers and room.


----------



## jmschnur (May 31, 2011)

Sure. Room first speakers second .


However the synergy between speakers and amp need to be considered as one strives for the best sound.


----------



## gsmollin (Apr 25, 2006)

bluemax_1 said:


> I don't think you're understanding the idea of the challenge properly... Max


Well, no, I do think I understand the challenge properly. Here is what I think it says: "All high fidelity amplifiers, operating well within their limits sound the same." Clark apparently went on this crusade because marketers from audio companies were claiming their amplifiers had, as you said, "pixie dust" in them, and were doing things that were beyond the ken of mere mortals to understand. I have seen many such claims, not only for amplifiers but for even simpler things like speaker cables, where you actually can't even measure the difference between $20 zip cord and $2000 pixie dust. At least you can measure IM distortion differences between similar, "properly built" amplifiers.

I don't have any argument with the challenge's premise, driven by $20k amps claiming to be better than mere $15k amps, when, actually, neither one is substantially better than a $1k amp.

My argument with the challenge is that there are problems with the simple act of connecting various amplifiers to various speakers and placing them in various rooms, and that these combinations do sound different. The cause of the differences is usually due to the speaker and room, but occasionally an amplifier problem crops up. The deficient amplifier may not have been designed to drive the speaker, so replacing it changes the sound. Hence the claims that amplifiers can change the sound. Was that amplifier not "properly built"? Maybe, but it was also made by a major manufacturer who sells tens of thousands, and the problems are real. When there _are no problems _, then yes, amplifiers all sound pretty much the same. I think the challenge would have served audiophiles better if it had shown that when there are audible differences they come from identifiable, and correctable sources. But this wasn't Clark's agenda, and it was his "amplifier challenge" after all, so there it is.


----------



## showcattleguy (Jun 30, 2011)

I recently heard a Class D offering from Bell Canto i believe that had a very unique sound compared to the Class A/B McIntosh with which I am accustomed. The McIntosh was very authoritative, maybe a little more mellow, and just had a sweeter sound. I didnt really believe there was much of a difference until i had the opportunity to hear the new configuration. Also both power amps were similarly priced. I heard enough to make me give up on Class D switching amps.


----------



## AudiocRaver (Jun 6, 2012)

gsmollin said:


> My argument with the challenge is that there are problems with the simple act of connecting various amplifiers to various speakers and placing them in various rooms, and that these combinations do sound different. The cause of the differences is usually due to the speaker and room, but occasionally an amplifier problem crops up.


Big agreement here, the test methodologies to be used in "The Challenge" matter greatly. A true double-blind setup with quick-switching capability - in the range of a few seconds - would be called for. Then there's the question of what "golden speaker" would be selected for that setup, and of course you'll never get universal agreement on that decision. Even the best thought out double-blind approach will have some listeners claiming that the setup somehow masked the very differences that it was supposed to allow the listener to try to hear, making the whole test invalid. Sigh. But all we can do at this point is use our best science and a single double-blind test room, which I believe would show that all well designed amps - designed NOT to color the sound, with flat response and near-zero distortion - not being over-driven during the test, will sound the same.

For those who believe otherwise, there is no valid proof _to them_ that their belief is incorrect. That's where respectful disagreement comes in, and who am I to tell someone what she/he can or can't hear? Peace and love!:T


----------



## JerryLove (Dec 5, 2009)

You basically have to trick them into naming two sufficient amps (perhaps which they already have in their house) which "obviously sound different". 

Fortunately: the same crowd tends to believe that audio memory lasts more than a few seconds; so you can do what is really a bad ABX test and manually switch the cables rather than try to use a pair of matched speakers.

Of course, if they can't tell the difference a few seconds apart: then how did they notice the difference.

Sometimes there really is a difference. If someone's trying to run their Maggies off their Sony AVR (assuming the AVR doesn't actually melt) that won't sound good; and a real amp will be clearly different.

But a difference between a 300w Adcom and a 300w McIntosh running a set of (say) Paradigm S2's at (say) 50w peak output? No.


----------



## MagnusAtom (Oct 23, 2012)

I had some trouble loading the photos from the iPhone App. 

Anyway, here it is: 

Both amps cost almost as much as the other, everything else remained the same, big speakers, duo mono configuration amps with separate power supply, top of the line SACD/CD player. Only the Amplifiers are different, but played over the same overall SPL, with the same Pseudo Noise tones. Both amps hardly, hardly stressed as you can tell from the SPL on the graph. 

The difference is that one sound thumpy, solid punchy bass, lack mid range- classical guitar tones for example, were less full and round as they should be (the other amplifier replicated it perfectly), and more exciting highs, which made the overall sound seemingly more exciting. The other amplifier was just smooth and overall, fantastic sounding. 

I hope this does state clearly that amps differ from one another. Emotiva is the best value for money amp. For most parts of the reproduction, it sounds great. There are details that seemed lacking versus more expensive amplifiers that I've heard, at a low or high volume.


----------



## 3dbinCanada (Sep 13, 2012)

MagnusAtom said:


> I had some trouble loading the photos from the iPhone App.
> 
> Anyway, here it is:
> 
> ...



Can you add some detail to the graphs as its hard to read? Does each graph represent two different power amps at two different power output levels?


----------



## GranteedEV (Aug 8, 2010)

jmschnur said:


> Sure. Room first speakers second .
> 
> 
> However the synergy between speakers and amp need to be considered as one strives for the best sound.


Why?


----------



## MagnusAtom (Oct 23, 2012)

Both the graphs' thick lines represents the sound recorded. Ignore the thin line at the bottom of each graph. The only difference between the set ups during the recording is the mono block power amplifiers. The volume taken from an SPL meter showed an overall same-decibel reading, in the same room, measurements taken one after the other. 

As you can see, the graph above showed bass frequencies that influences the speaker to be more punchy because of a slight dip in the range shown on the first circle from the right, and less roll off highs towards the end, there was a dip in the mid-high frequency versus the bottom graph; it has less disparity on the lower bass and the upper bass, the bass heard was that the bass was defined, but not necessarily punchy, building up towards 1kc, was a bump. Music played showed lots of richness which was extremely enjoyable, and not found in many solid state amplifiers. This gave instruments a lot of detail, very natural guitar tones, texture on stringed instruments on classical was more presentable, and took less effort to hear. Piano pieces were again, rich, and full bodied. The graph above sounded "faster", and seemed cleaner, forsaking the texture and tones of instruments, but overall excellent sound still. Piano sounded lively. 

Now, both are great amplifiers, but for comparison sake (during the measurements-which were done about a month before I participated in this forum), I wrote down my impressions of each amplifier within the setup, only known to me as Brand A & B, and was later shown the curve, which made sense to me, and I could relate to the responses. 

The curve represents the overall sound of the entire system in the room when looked at individually, and to me, it doesn't look bad. The room's SPL stands at about 44dB when absolutely quiet, so looking at about 70db there 'abouts isn't so loud, which tells me from experience that an estimate 500 watt amp at 8ohms on an 8ohm speaker that is 88dB in sensitivity, is working effortlessly with plenty of headroom seating about 10ft away. This can be mathematically calculated if necessary (on absolute, without external environmental considerations). 

Marantz receiver vs McIntosh power amplifier sounds different even at 1 watt. Theta Digital vs Mark Levinson upright mono blocks sounds different. Emotiva XPA-1 vs a Krell Evolution sounds different. Unison Research vs Audio Research sounds different, Pass Labs vs Karan sounds different. Pioneer vs Marantz sounds different. McIntosh's lower models vs higher models have similar tones in general, but different performance and presentation even at 1 watt - I'll explain this, at the sweet spot seat, an MC1.2KW will have more depth, contrast between quiet levels to music phases, ability to do transients better within the values of the lesser model- headroom is also very much appreciated. A 250 Watts integrated McIntosh MA7000 vs a 200 watt integrated MA6600 sounds different at 2.5 watts. The bass is much better delivered vs the MA6600. 

There are only so many ways a normal amplifier is built. Input stage, Amplification Stage, Output Stage. Amps sound the same when all components are used equally - or within the elasticity of a slight change in frequency responses that our ears are not sensitive to pick up. For those that believe that different designed amplifiers sound the same at 1 watt, good for you, you merely need the basics to get you by, less outlay on the pocket. 

For those that think amps sound the same, you could say we prefer the drive and performance of a Ford vs a Chery QQ; they are hardly the same even getting you one place to another at 40miles/hour. The only similarities are the functions - that they are cars that get you from point A to point B, with seats, a handbrake, a steering wheel, wipers for rainy days. 

Does an amplifier color sound? by its definition, it is not supposed to. it is only meant to amplify signals. however, in the real world, amplifiers have sonic characteristics, which can be due to many different reasons: measurement tools used by manufacturers are not as accurate as others, components meet values, however due to inferior quality, degrade the quality and transparency of signal transfer. Chassis in the matter of damping vibration caused by large transformers demand of supply, affects in quiet levels, contrast in sound presentation - while will in turn, will color the exact response of what should be a neutral amplifier. Also, addition of protection circuitries, sensing circuitries, ensuring delivery of stable power at varying ohms are also challenges manufacturers face against speakers, and these may also influence the eventual sound of the amplifier. Integrated amplifiers share power supply in a manner of two-in-one function will also depreciate the overall sound vs separates, spec-ed at the same wattage. 

So yes, amplifiers in the real world sound different from one model to another unless their ingredients are identical or too similar. Get the room right, and get the flattest response speakers on and off axis, then think about what amplifiers drive the speakers best, to best measure a perfect flat line vs the curve attached earlier from the overall room. That would be truly an honest/transparent system, once you are about that response, its up to you do do what you prefer for your ears and your money. 

Another thought: marketing for the lesser companies may inform audiences that it doesn't matter what amplifiers they buy, they are all the same, the only difference is the look! might as well purchase a high wattage amplifier at a fraction of the price and get great sound. It's all the same anyway! And these are mono blocks! Oh yes, we are not certified for fire safety, and we don't believe in middle man fees- and charge customers higher than they would dealers on a rebadged model (great commission!).
Think about the idea! 3x500watts mono block for LCR, how awesome is that on paper?! An Emotiva set will cost less that $3k for that, and about $18k for a McIntosh, for the same wattage RMS! 

Come on. 

Amps may color sound, but we don't know which amp has the flattest freq res 5hz-100khz, or 20hz-20khz. I'll say from the little experience I have, amps don't sound the same- it is the overall curve of the entire system, including the room that matters most, but it is only as important as your choice/decision of the degree of fidelity.


----------



## MagnusAtom (Oct 23, 2012)

GranteedEV said:


> Why?


Actually, it really depends on your ears/choice of degree of fidelity. 

If you like a brilliant tone, and something lively, you start off with a speaker designed that way - eg, metal tweeter, big woofer. 
You like the tone of the speaker selected, and you want to keep that tone, you look for amplifiers that are as flat on the bench as possible. If you feel the speakers are too brilliant, but love the depth it has, the common approach is to use a tube. Or if you feel you need that little more push of liveliness, then you get a typical sounding SS amplifier. Or you like tight bass, and love the effect big woofers have, look for a high powered amplifier with a high damping factor, which will typically tighten the bass - neat, big woofer with deep bass, and great tight control with the amplifier. Typically, the later the electronics in line the more effect it has on the eventual sound. 

Just examples. 

As an ideal, the speakers and room interaction should result in the flattest curve possible, so high fidelity is intact- and for the listener to hear EXACTLY the details in the recording, without compromise. It is almost impossible to achieve that in our practical living, 

Some manufacturers believe there is a certain frequency curve our ears are most inclined to, and design great sounding speakers/amplifiers that way.


----------



## jmschnur (May 31, 2011)

GranteedEV said:


> Why?


Impedance changes can be a big factor for some amps with some speakers. Some amps do well with impendece varying from 0.1 ohms to 15 ohms in pne speakers. some do not. Also the damping factor can make a real difference with some speakers in some rooms.

Listening can discern these effects to lead youvtovbest matches between speaker and amp. First speaker, then room, then match the amp to the speaker , then gett best low distortion pre one can get, then good material .

However, each to her/ his own in terms of taste.


----------



## AudiocRaver (Jun 6, 2012)

A good point has been made - we tend to think of power amplifier nonlinearities occurring mainly at or close to the clipping level, but there can be speaker & environmental factors that coax different nonlinearities out of different amps even at levels way below clipping.

One assumption of this discussion has been that in "properly designed" amplifiers all these below-clipping nonlinearities have been ironed out and made equal, but perhaps that is not always the case. Perhaps it is not even possible.

I'm reminded of an early engineering job with an audio manufacturer, now long gone, where our chief circuit designer had a major challenge convincing the bosses that Transient Intermodulation Distortion even EXISTED. He finally ended up designing a circuit with good "standard" bench specs and grossly exaggerated TIM with the right signal/program material, and let their own ears do the convincing, which led to a new family of designs for that company. Knowing what to look for, new bench measurements were implemented so we could measure slew rate and test for the causes of TIM directly, and we all ended up a bit smarter about how an amplifier can _sound_ and how to design circuitry that measured well and sounded good, too.

That said, we've come a long way, and absent a true double-blind, volume-compensated, quick-switch test setup with the amplifier the only variable, I still tend to believe that amplifiers intended to have flat response and little-to-no distortion and equivalent damping factors and running well below clipping - will sound the same. And if they don't, one of them needs some more drawing-board time. Probably. I would truly appreciate the opportunity to participate in a well-thought-out demo that shows otherwise. I am teachable. A little.


----------



## primetimeguy (Jun 3, 2006)

MagnusAtom said:


> I had some trouble loading the photos from the iPhone App.
> 
> Anyway, here it is:
> 
> ...


Can you provide better graphs? Very hard to tell what is going on from those charts. Change the scale rather than 20db per division and also show them on the same plot so we can compare rather than looking at circles?

Also, what smoothing is applied to the charts and what is the repeatability of the measurement device?


----------



## JerryLove (Dec 5, 2009)

primetimeguy said:


> Can you provide better graphs? Very hard to tell what is going on from those charts. Change the scale rather than 20db per division and also show them on the same plot so we can compare rather than looking at circles?


 Agreed.

My thanks for putting these up, and my sympathies for your difficulty with the iPhone app (which app?)

Multiple runs would be nice: Especially "A then B then A then B" order to help reduce the chance that room changes are the issue. (I assume the mic is in a fixed location)

The must be large speakers indeed to have no dropoff at 20Hz. What speakers were you powering? (and in a shockingly neutral room).


----------



## MagnusAtom (Oct 23, 2012)

Speakers were Focal Maestro Utopia. 

Assumption that the mic was in the same position is correct.


----------



## MagnusAtom (Oct 23, 2012)

It was only the third time using the measurement system during the recording, hence the curves weren't saved the best way possible. But you can try placing them above each other from power point, copy the image and superimpose them above the other, and increase the transparency. You'll see the curve generally takes the same shape, because room, speakers and system are not touched, just amps. The differences would be amplifiers then. 

Since then, I've measured a couple of rooms, and have learnt how to save graphs properly for direct comparisons. The measurements have helped me design acoustics, and translate audio opinions to curves and associate frequency ranges more accurately. 

I had the rare opportunity of sitting in with 4 amps in a semi blind shoot out. The measurement tool would have been so useful-if only I had them then.

We'll have better graphs in future. ")


----------



## MagnusAtom (Oct 23, 2012)

AudiocRaver said:


> A good point has been made - we tend to think of power amplifier nonlinearities occurring mainly at or close to the clipping level, but there can be speaker & environmental factors that coax different nonlinearities out of different amps even at levels way below clipping.
> 
> One assumption of this discussion has been that in "properly designed" amplifiers all these below-clipping nonlinearities have been ironed out and made equal, but perhaps that is not always the case. Perhaps it is not even possible.
> 
> ...


I think some amps have similar characteristics-just at different degrees. But those that sound exactly the same, I've not heard. 

Could you point me to models that I could maybe put together to audition them? Based on your personal experience, you may be right, but I would like to hear it for myself, if they are within my means. 

Thanks.


----------



## bluemax_1 (Feb 14, 2011)

MagnusAtom, 

are you claiming that the Emotiva XPa-1's are not flat?

If so, care to explain these independent review and measurement results? They're certainly easier to read than your smoothed out graphs with 20db spacing.

http://www.hometheaterhifi.com/powe...view98/page-4-emotiva-xpa-1-on-the-bench.html

Of course, the graphs in the link are pure input-output measurements, unlike room measurements where who knows what the rest of the equipment chain is doing. The ability to isolate the results to a specific component makes reviewing the results a lot easier.

As I mentioned in previous posts, sure, one could take a bright sounding speaker with a boost in the treble, and then mate it with an amplifier that rolls off the highs, but why do that? It simply makes more sense to choose an entire equipment chain that is flat. Speakers that play flat, amps that do not alter the frequency response of the signal, cables that don't attenuate certain frequencies to produce a specific 'cable sound' etc.

With flat equipment, you can place it in any room, then measure it and see what needs correction in the room. With equipment that is all over the board, sure you need this amp for that speaker because you need the distortions of one to cover the distortions of the other. Amps shouldn't be tone controls, neither should cables, interconnects or any of these other pieces of equipment.



To sum up my position, the original question in the thread title has a simple answer:

Do Amplifiers "color" sound? Not if they're designed and built properly.



Max


----------



## GranteedEV (Aug 8, 2010)

MagnusAtom said:


> If you feel the speakers are too brilliant, but love the depth it has, the common approach is to use a tube.


being a common approach does not make it a sensible approach. If you feel the speakers are too "brilliant" then they were the wrong speaker in the first place for you.



> Or you like tight bass, and love the effect big woofers have, look for a high powered amplifier with a high damping factor, which will typically tighten the bass - neat, big woofer with deep bass, and great tight control with the amplifier


Any moderately decent damping factor (an "inverse word" for low measured output impedance) will not affect the sound. Further, unless you know explicitly the speaker's impedance curve in frequencies above the bass, using any amplifier with a sufficiently high output impedance is just a bad move anyways. Why would one make a move which is clearly not sensible?



> Impedance changes can be a big factor for some amps with some speakers. Some amps do well with impendece varying from 0.1 ohms to 15 ohms in pne speakers. some do not.


Obviously there's a bare minumum of bad design which is unacceptable. This starts at the speaker of course - if the speaker's impedance curve is needlessly difficult, than that's a speaker design issue. If the amp can't drive a moderate load, then upgrading amps is not a "bonus" as you imply but a necessity and should have been done from the very beginning.

My understanding of your earlier implication was that once good sound has been achieved - it can surely be improved by upgrading electronics. I disagree based on my experiences. My basic assumption is that the amplification is adequate with respect to the loudspeaker load and headroom. If the speaker requires some extreme amplification, then clearly there is a speaker issue. If the speaker already sounds great, then electronics will not make a meaningful difference because they are literally 5% of the sound - which gets masked by the speaker and the room. Even if a preamp has 0.0001% distortion instead of 0.003% distortion for example - it won't matter - it will all be masked by the speaker's .1 to 3% distortion. It's not that once you've sorted things out, then the electronics can only improve things - but rather that once you've sorted out the speakers and room, you've sorted out the sound.

Trust me, I understand that electronics aren't perfect. For example, whereas a speaker's distortion will only drop as SPL demands drop, many class AB amplifiers will have a rising distortion as voltages drop.

But this does not automatically mean it will be audible, either. A 5th harmonic at -50db (which is 1% distortion and higher order too!) sounds bad... except for one thing. If your SPL is 40dbSPL, then that means that 5th harmonic is at.. 10dbSPL. 

There are a lot of measurable issues in electronics. But that does not mean they are audible, so chasing that goal does not mean that anyone looking for the best possible sound needs to chase great electronics. 



> Also the damping factor can make a real difference with some speakers in some rooms.


But do you have empirical evidence of this in an anechoic space before we even mention the room?

Even besides that, all rooms have a vast masking effect on system effects. So if the above case were true (that the damping factor makes a difference anechoically) it would still be subject to the effect of the room below the shroeder frequency. This will absolutely mask this already minor abboration at system resonance.



> Listening can discern these effects to lead youvtovbest matches between speaker and amp.


Blind, 0.1db level-matched listening? Or does it need to be sighted, random level listening?


----------



## MagnusAtom (Oct 23, 2012)

I was just stating- I do think we need the speakers to perform best on/off axis, 30-60. No speaker does this perfectly. But there are speakers that look real good on charts off the anechoic chamber. 

So it doesn't matter how accurate your set is on the bench until it is put into the room, and measured. It does point us in the right direction though. It really depends what people do with what they've got and the degree of fidelity they are content with. 

So match the speaker with the room if you're being technical. Otherwise match the room to the speaker. No right or wrong approach, as long as the sound is accurate at the final measurement. 

Amps have different sounds, we just don't know which is the flattest/quietest at all frequencies, and one that manages all resistance the best. And know them truly. There is no one-body within the audio industry that is an authority enough to certify these things.

On another thought, perhaps bi-amping would be best, because lower frequencies seem to vary most in resistance, and requires good solid amps to keep pace.


----------



## MagnusAtom (Oct 23, 2012)

The graph indicates any changes in frequency response. I did not do it with the intention to point out any scientific proofs. But it does show varying frequencies between the set ups, with only variable being the amplifiers.


----------



## Savjac (Apr 17, 2008)

Lessons learned from this most excellent post.

If you believe that amplifiers color the sound then YES they do and ways will be found to theoretically prove that belief.

If you do not believe that amplifiers color the sound then NO, they do not and ways will be found to theoretically prove that belief. 

There, that sums it up. This appears to be a very personal issue.


----------



## JerryLove (Dec 5, 2009)

Given the speakers (and if I understand one of those amps was an Emotiva); therre likely is coloration. The Focal Maestro Utopia is a 3ohm speaker (per Focal: the Stereophile measurement spends real time at 2ohm), and Emotivas are only rated down to 4. 

From Stereophile: As taxing as this will be for an amplifier, there are combinations of 3.75 ohms and –37° phase angle and 2.3 ohms and +40° at 62Hz and 126Hz, respectively, which will also demand very high currents from the amplifier. As all music has considerable energy in this region, the Focal's owner will have to use an amplifier that can genuinely deliver high powers into 2 ohms if the speaker is to be allowed to sing as it should. Even then, as I found with the otherwise superb Simaudio W-7 amplifier, the high phase angle at infrasonic frequencies may well cause the amplifier to go into protection with a wideband pulse as it encounters what appears to be a short circuit on its output.

I have the same issue with my B&W 801N's. That's why I don't run them on Emotiva (I can hear problems). 

Though if we go back to my "two kinds of amps: sufficient and insufficient" position; I'd assert that an Emo is "insufficient" for loads <4ohm.

We'd want to compare certain models of Krell, McIntosh, Parasound, and perhaps Crown (all of which have 2Ohm amp models) if using those speakers.

I thank you very much for putting up the graphs and taking the time: but I'm afraid (unless I misunderstand what amps you were using) you have supported what we already agreed on: insufficient amps color sound.


----------



## steve1616 (Apr 6, 2009)

One other thing to add to the equation is that I have the same sub in my room and if I take a different frequency response chart even throughout the day, they will look different. That is why the anechoic chamber is the best way.


----------



## MagnusAtom (Oct 23, 2012)

Anechoic chambers are best for measurements. 

Amps used for measurements were not emotiva, although we have compared them on a separate listening sessions with 4 other solid state amps. With three of them having similar characteristics, and differences were heard- mid range was the main debate, and bass control was the next significant factor that was different. The amps were emotiva, theta digital, mark levinson, McIntosh during the listening session. 

Maestros are supposed to be rated at 8 ohms, I clarified with Focal staff, and the Internet specs is not correct, their manuals and brochures will also show 8 ohms. 

The requirement for the high resistance is found on the lower frequencies mainly. Overall room is catered to the speakers. Hence, a pretty nice curve from the overall room. 

Are you suggesting that if I placed a bookshelf speaker, that does well within 4 ohms minimum, and 8ohms nominal, putting back both amplifiers and measure, I will have the same response at say 50db or about 1-12 watts on amplifiers that will do minimum 500 watts on 4 ohms? 

in the topic where amps color sound, it depends on speakers paired with it, and room the speakers are in. 

Universally with no exceptions, amps do not sound the same, regardless of power, and capability. In a way, amps sound the same if they are specified to be the same, and I believe that can be achieved. But in the real world, you pick out a bunch of 10 amps on your wish list, chances are that they will be different, because top-end brands sound different as they are designed differently, using various components that influence the sound- it would be matter of the degree, and critical-ness the user is. I'm pretty sure the mic will also reflect the difference.

Another thought: The idea that amps are built the same is could have the same impact as Pre-amplifiers sounding the same, since they are less subjected to varying external environments. Input from source to volume controls, and output to amps. Lesser voltage, not needing, to contend with speaker ohms, or cd sources sounding the same. Oppo 95 uses ess sabre 32 bit DAC, hardly sounds the same as a McINTOSH mcd1100 on ess sabre 32 bit DAC. 

If all amps sound the same, there is no need for technical differentiation in this case, just look for the components that look the prettiest. 
We would be undermining engineers from the manufacturers severely, who take great pride in their work if we agree to this don't you think?

Again, amps may sound similar, I will accept, but amps from different brands (non rebadged) will sound different or not exactly the same, when it comes down to listening for details & tones, and dynamism among others.

Appreciate your summary. 

Thanks.


----------



## JerryLove (Dec 5, 2009)

MagnusAtom said:


> Maestros are supposed to be rated at 8 ohms, I clarified with Focal staff, and the Internet specs is not correct, their manuals and brochures will also show 8 ohms.


The speaker mentioned as being the one used to create the graphs tests as 2 ohm minimum. Please see the link I provided earlier from Stereophile.



> Are you suggesting that if I placed a bookshelf speaker, that does well within 4 ohms minimum, and 8ohms nominal, putting back both amplifiers and measure, I will have the same response at say 50db or about 1-12 watts on amplifiers that will do minimum 500 watts on 4 ohms?


I'm not merely suggesting: I've stated that (generally speaking: there's more than ohms to worry about) yes, they will sound and measure identically.

I'd be happy to ABX test that theory. If I get the gumption: I may setup my mic and pull multi-run graphs on level-matched amps in my living room (the FR chart will be messy, but should line-up)



> in the topic where amps color sound, it depends on speakers paired with it, and room the speakers are in.


How does this even make sense? How does a room affect an amp?!? An amp has no knowledge of soundwaves once they leave the driver.



> But in the real world, you pick out a bunch of 10 amps on your wish list, chances are that they will be different, because top-end brands sound different as they are designed differently


In the real world there was a public $10,000 offer that they didn't (again: excepting amps *deliberately* coloring sound and amps insufficient to the speakers being driven).

In the real world (because this challenge was taken to audio shows) hundreds of people tried.

In the real world no one could tell the difference.



> I'm pretty sure the mic will also reflect the difference.


You have some hope that the mic will find something. It's more sensitive than your ear. Though "flat beyond human tolerances", no amp is *completely* flat. There's always some resolution that they will not be.

The problem is the temperature in the room is going to have more effect. With a sensitive enough mic: you won't get two measurements to match even on the same amp.



> Oppo 95 uses ess sabre 32 bit DAC, hardly sounds the same as a McINTOSH mcd1100 on ess sabre 32 bit DAC.


This feels like a red herring



> If all amps sound the same, there is no need for technical differentiation in this case, just look for the components that look the prettiest.


Once you establish sufficiency to the speakers: yes. The differences are about efficiency, reliability, and aesthetics. 



> We would be undermining engineers from the manufacturers severely, who take great pride in their work if we agree to this don't you think?


Yep. Remember the psychic from the 70s who the universities started showing as proof of all their hard work? Remember his response when asked how he did it?

But I don't think that as large a percentage of amp builders as you seem to think actually assert that there's a difference in sound. More a difference in quality and ability.


----------



## Savjac (Apr 17, 2008)

This is not meant as an insult, but one must ask, how is it that so many folks who actually took the test as laid out earlier in this post, were unable to reliably tell the difference between products. This surely cannot be a scam, but there must be something to this train of thought if thousands of folks, including some golden ears cannot hear the differences we are extolling here. Have any of us tried the test ? $10,000 is a good deal of money.


----------



## MagnusAtom (Oct 23, 2012)

JerryLove said:


> The speaker mentioned as being the one used to create the graphs tests as 2 ohm minimum. Please see the link I provided earlier from Stereophile.
> 
> I'm not merely suggesting: I've stated that (generally speaking: there's more than ohms to worry about) yes, they will sound and measure identically.
> 
> I'd be happy to ABX test that theory. If I get the gumption: I may setup my mic and pull multi-run graphs on level-matched amps in my living room (the FR chart will be messy, but should line-up)


I will conduct the experiment. Focal Chorus 806v. Let me know if there's anything about this speaker that is beyond the capabilities of amps that will do 4 ohms.

QUOTE="JerryLove;562495"]
How does this even make sense? How does a room affect an amp?!? An amp has no knowledge of soundwaves once they leave the driver. [/QUOTE]

Sound heard by the listener is influenced by the room, speakers, amps, etc. you will never know if the amp colors sound if you don't know what the amps sounds like in the first place. Practically, you'll need a source of reference. This is merely the next best scenario. 



JerryLove said:


> In the real world there was a public $10,000 offer that they didn't (again: excepting amps *deliberately* coloring sound and amps insufficient to the speakers being driven).
> 
> In the real world (because this challenge was taken to audio shows) hundreds of people tried.
> 
> ...


I will investigate. I hope he qualifies my amp choices. 
Hundreds of people is not a significant number against the number of people who choose their stereos because of sound. I have taken some tests and have done well in them. I don't know the scores of hundreds of people, but these tests explores hearing sensitivity, and familiarity of frequencies, and I'm pretty sure, being free, many would have taken them too. 

I think what would encourage people to take the challenge is if they were more transparent in how the tests are conducted, list qualified amps and models. I'd buy those amps and try them out myself, and not have to pay admission fee for a hypothesis. 

Before this thread, I never knew that $10,000 was up for grabs. 

Regarding the mic, I think, within reason, a person can tell the difference in 3dB bump in a frequency response. I took a Harman Kardon test that did that. Full marks. 
There are frequencies there that we can't hear- fine. But in the middle chuck of the curve is something we can. And if the mic shows differences by at least 3dB at some frequencies, it would be reasonable to believe that there are differences. I'm likely to believe temperature affects sound in some way, but not at 3dB, and at the expense to say the same amp will sound different because of room's temperature. 



JerryLove said:


> This feels like a red herring


Well, the point is that it may have similar parts, but every board in the chassis plays a part. Just as it does for amplifiers. Technicians/music lover friends have replaced parts in an amp with inferior-though same value components on an amp. And it sounds different from the original (Always best to get original parts from manufacturers or the exact parts used by the manufacturer). 



JerryLove said:


> Once you establish sufficiency to the speakers: yes. The differences are about efficiency, reliability, and aesthetics.
> 
> Yep. Remember the psychic from the 70s who the universities started showing as proof of all their hard work? Remember his response when asked how he did it?
> 
> But I don't think that as large a percentage of amp builders as you seem to think actually assert that there's a difference in sound. More a difference in quality and ability.


HAHAHA. Ok, you may be right there. But only as right as I am. 

I hear you on build quality, reliability. It is also in these factors that influences the sound of the amplifier. Quality on rigidity of chassis, and absorption of vibration, thermal management affects sound- some in contrast of quiet levels to music phases. Quality components makes amps more reliable, and the difference in that quality has a difference in sound. I know some amp engineers that have different views on sound.

Some speaker engineers I know personally have personal preferences on amps used for their speakers ; they know which amplifiers serve their speakers best- but none have exact sounds, but only similar sounding ones. 

One of them whom I just spoke to, discussing this thread, believes amplifiers have different sounds, and that our brain is intelligent enough to differentiate the differences even with little variables. We discussed certain designs of amplifiers having different designs to handle different pressures from the amp because of the speaker design, and even then, two brand amps with a similar approach will not do these the exact same way, influencing sound reproduced by amps, and there's an audible difference. 

Anyway, I'd just like to share the following picture.


----------



## JerryLove (Dec 5, 2009)

Wow.

Thanks for the post and the picture; and thanks for taking all the time to do these experiments! 

Looking at the speaker's measurements: I would think that one would be an excellent one to test multiple amps on; as there are many amps that (as far as I can tell) should be sufficient to full drive it.

I love your speaker choices BTW. 

Bluntly: If I'm wrong, I want to know. It give me another place to direct my time and study to improve my sound.


----------



## MagnusAtom (Oct 23, 2012)

Jerry, I must say that I'm surprised at the similarities the sound is when plugging those amps into the bookshelf. 

Nevertheless, on a blind test, we found that we still could pick out one amplifier from the other all the time, although much harder.

Now, I can understand where you are coming from. I can imagine amps with similar characteristics will sound even closer. 

We heard vast differences with the big speaker and less with the small speaker, nevertheless we were able to pick out one from the other. One amp was again smoother/rounder. This time, highs were clearer, bass was full, where as the 'typical' designed amp was more mellow, however still sharper, more spacious, but not as crystal clear now, and not punchy. 
The punchy-ness was completely gone, as speaker just would not play frequencies below about 55hz, and hardly invoked musical body in the room. 

We then looked at the curve:

The curve recorded showed very little change- between 1db to 2db at certain frequencies, and as a general rule, an obvious difference consideration would be 3db. They were the same at certain frequencies even. 

Conduct:
Mono block Amps were brought out. Must have weighed 120lbs each! 
had my friend facilitate the test. He did all the connections. Perimeters of the experiment were
Same speakers throughout, same electronics throughout, same cables throughout. Only variable are two mono block amplifiers. One on each side of the room. 
I left the room while my friend did the rest of the work. I had no clue which was going to be played, and had no immediate last memory of the system's sound. 

On the first sitting, after about twenty seconds of listening, I told my friend facilitating the test my answer, and was right. I left the room and when it was ready he called me back in. The amplifiers were all covered up, no one except him would know which was connected to the speakers. 

After a few sittings moving in and out of rooms, we determined the amps were identifiable. The wattage played was about 1-10 watts, at about 70 db peak, 65 on average. 

Conclusion, smaller speakers do not require too big an amp to drive, because it doesn't provide much value for money. Smaller speakers do well enough with smaller amps. A three way speaker may not be the same because bass resistance varies.

If you dabble with small speakers, i guess you don't have to be as particular with amps. 

Bigger woofer speakers will require big amps to drive, because you'll need an amp stable enough to manage resistance of up to about 2ohms typically to get better values off the speakers. Unless you have real sensitive speakers, then the same would probably apply to the paragraph above, the amplifier influence is less. 

Amps have sounds. I think there is no doubt about it. Just need to care which speaker you play them off. I think you'll never know the difference until you put them side by side, or unless you are very critical. Thank goodness I picked my amps correctly, otherwise I'd seriously be doubting myself, and all those years of advocacy on high fidelity components!

This was an enjoyable experiment. I hope shack readers gained something out of this. 

Thank you.


----------



## Savjac (Apr 17, 2008)

Quite the interesting threat and opinion set.
I did several very lengthy tests between different quality amps, Macintosh, Luxman, Audio Research, Grand Integra, Adcom, Hafler and conrad johnson. These were powering either Dahlquist DQ10's or Magnepan MG2 and Acoustat 3's.

We could hear differences in Preamps, turntable cartriges, some cables, most were similar but Amps was another story. The only one that seemed to stand out from the others was the conrad johnson premier one in that it had incredible power reserves, there was no denying it could not only drive the Acoustats but could make the sit up and beg. I really cannot define why that amp sounded so powerful even at the same levels the other amps were run at, using a db meter. THe AR seemed to work especially well with the Maggies, but we could not always tell. The solid state amps, we could not reliably guess what amp was driving either of the speakers. This was very scary when we did out first big Japanese amp, the Luxman 5M50 to the awesome Mac MC2250. We could not for the life of us hear a difference. And we had been listening for many years. The Mac had double the power and yet....no audible difference with our volume choices.

I remember this so very clearly and yet, others hear the difference. Humans, we are all so very different. That is a good thing.


----------



## 3dbinCanada (Sep 13, 2012)

Savjac said:


> Quite the interesting threat and opinion set.
> I did several very lengthy tests between different quality amps, Macintosh, Luxman, Audio Research, Grand Integra, Adcom, Hafler and conrad johnson. These were powering either Dahlquist DQ10's or Magnepan MG2 and Acoustat 3's.
> 
> We could hear differences in Preamps, turntable cartriges, some cables, most were similar but Amps was another story. The only one that seemed to stand out from the others was the conrad johnson premier one in that it had incredible power reserves, there was no denying it could not only drive the Acoustats but could make the sit up and beg. I really cannot define why that amp sounded so powerful even at the same levels the other amps were run at, using a db meter. THe AR seemed to work especially well with the Maggies, but we could not always tell. The solid state amps, we could not reliably guess what amp was driving either of the speakers. This was very scary when we did out first big Japanese amp, the Luxman 5M50 to the awesome Mac MC2250. We could not for the life of us hear a difference. And we had been listening for many years. The Mac had double the power and yet....no audible difference with our volume choices.
> ...


Were these sighted tests or blind listening tests? I find sighted tests only offer up a listener's personal biases rather than focusing on what really matters, the sound. If levels are matched and all amplifiers are running well within their power limits, then it will be impossible to consistently choose which amp is driving the load. Only when you begin to push the power envelope do the differences come out.


----------



## Savjac (Apr 17, 2008)

These were semi blind, we shut our eyes, at least I know I did. The key here is we tried this over a period of weeks not minutes and it was so difficult to pick. Even when I knew, knew that one amp was playing, it was never more accurate than if I were guessing. I am a musician, have attended hundred of concerts of all kinds, 10 years as a patron at Chicago Symphony Hall, 5 years at the Opera House until the tickets got sooooo expensive so I thought I knew. Maybe playing the guitar and going to large venue concerts was not the best thing eh ???

The power envelope with the amps did not matter. They would all outlast anything I cared to listen to and frankly the speakers would go into melt down before the amps would change timber.


----------



## 3dbinCanada (Sep 13, 2012)

Savjac said:


> The power envelope with the amps did not matter. They would all outlast anything I cared to listen to and frankly the speakers would go into melt down before the amps would change timber.


Maybe I was not clear enough in my statement. Given to amps, one high powered, the other moderately powered, the load being such that even the moderate powered amp could drive the speakers to comfortably loud levels, as long as outputs were level matched, it would be impossible to tell them a part. Its only when you pus the moderately powered amp such that it goes into clipping at the extreme point is where one would hear sonic differences.


----------



## MagnusAtom (Oct 23, 2012)

3dbinCanada said:


> Were these sighted tests or blind listening tests? I find sighted tests only offer up a listener's personal biases rather than focusing on what really matters, the sound. If levels are matched and all amplifiers are running well within their power limits, then it will be impossible to consistently choose which amp is driving the load. Only when you begin to push the power envelope do the differences come out.


Did a semi blind test-semi because I knew there were two brands on the floor, blind because amps were completely covered up, not even a hint of cables were seen connected to the amps, and picked out the amps correctly all the time. Amps do differ from each other. They may sound very close, but not identical as mentioned in my earlier posts. Again, both amps were very high powered amps (costing about as much as the other) driving a speaker with hardly any bass- it was a two way- this qualified my amps to be working effortlessly. The impedances should not have floated below 4 ohms on those. Focal 806Vs. 

The measurements came up very close, but there was still a difference, and that difference translated well when the preamp, with multi-band eq was used on otherwise was flat 0.: the measurements showed 200hz lower from amp a vs amp b. I raised it by a tad bit, and found tones to be even more similar- but still not the same. I thought I had concluded, so I didn't proceed with the 5khz knob adjustment. 

It was close, but difference is there. But difference was ALMOST as significant as changing cables from one model to the other. 

With all that said and done, I'd just say, go with what you like. Eyes and ears, for they are the consumers to enjoy, and if it makes you happy, who's to stop you. 

I'll give confidence to those who belief that amps differ in sound from one another. Because I experienced it, and I measured it, with consistent results that tally with my humble hearing. 

Only if you are using small speakers, I might just qualify that amps would MAYBE sound the same. 

On a side note, to Jerry and 3dbinCanada, or others who think amps do not color sound: what speakers do you use, to ensure the amps purchased is more than capable of driving the speakers without strain, to ensure the amp is performing up to conservative measurements? 

Those that purchase Emotiva, I would like to say, they are good amps, and truly best value for money. They do not rank the same as the bigger brands typically in my book, but excellent value for money, and look great! 
I have the utmost respect for McIntosh, especially their big models for delivering all the time, in my experience, no matter the size of the speaker. Build and reliability is No.1. 
For Oppo users using them for CD, please take time to conduct a shoot-out between sources, pit them against other brands like denon, marantz, even sony (for value) and others before making the jump. They are not like Emotivas in the realm of amps for Universal Players, and I have found them to be very over hyped.


----------



## 3dbinCanada (Sep 13, 2012)

MagnusAtom said:


> The measurements came up very close, but there was still a difference, and that difference translated well when the preamp, with multi-band eq was used on otherwise was flat 0.: the measurements showed 200hz lower from amp a vs amp b. I raised it by a tad bit, and found tones to be even more similar- but still not the same. I thought I had concluded, so I didn't proceed with the 5khz knob adjustment.


Were the same front ends employed? Were the outputs level matched? 



MagnusAtom said:


> It was close, but difference is there. But difference was ALMOST as significant as changing cables from one model to the other.


I'm a staunch non believer in cables emparting sound as there has been no scientific methodoloical tests done to date to indicate differences. Its all subjective here say... no offense intended. 



MagnusAtom said:


> With all that said and done, I'd just say, go with what you like. Eyes and ears, for they are the consumers to enjoy, and if it makes you happy, who's to stop you.


Not me.  Consumers should buy what they like.


----------



## MagnusAtom (Oct 23, 2012)

3dbinCanada said:


> Were the same front ends employed? Were the outputs level matched?
> 
> I'm a staunch non believer in cables emparting sound as there has been no scientific methodoloical tests done to date to indicate differences. Its all subjective here say... no offense intended.
> 
> Not me.  Consumers should buy what they like.


Output levels were matched to same dB on spl meter. 

Cables wise, no offense taken. Point is, the difference is little between the amps when they are not strained, hence understanding why it is said that amps are same as long as they are not strained. My blind test proved otherwise. I obviously heard the difference, and pointed out one amplifier from the other at least 6 times, 100% accurate. From the mic, seeing frequencies lower than the other amp, by boosting the frequencies on the preamp, the sound was even more similar. There were two frequency ranges that differ from the other amp. I only adjusted one. Perhaps by adjusting the other, we would have 98% same sound. Perhaps. But without adjusting, it could be identified, concluding amps sound different. 

Agree that consumers should by what they like, to their ears and eyes. As I mentioned. At the end of the day it's the consumers money, and self satisfaction. 

If two amps are packaged the same, and the buyer cannot tell the difference between amp A at $10,000, vs brand b at $1,000, aside from other factors like look, self assurance, one should pick the $1,000 amp. But if you can, then you should weigh if the difference between the amps if they are worth $9,000 difference to the buyer- to put it simply.


----------



## 3dbinCanada (Sep 13, 2012)

MagnusAtom said:


> Output levels were matched to same dB on spl meter.
> 
> Cables wise, no offense taken. Point is, the difference is little between the amps when they are not strained, hence understanding why it is said that amps are same as long as they are not strained. My blind test proved otherwise. I obviously heard the difference, and pointed out one amplifier from the other at least 6 times, 100% accurate. From the mic, seeing frequencies lower than the other amp, by boosting the frequencies on the preamp, the sound was even more similar. There were two frequency ranges that differ from the other amp. I only adjusted one. Perhaps by adjusting the other, we would have 98% same sound. Perhaps. But without adjusting, it could be identified, concluding amps sound different.
> 
> ...


You missed one question.. Were the source components and the source of music identical for both systems? I have to ask to be thorough.


----------



## MagnusAtom (Oct 23, 2012)

Exactly the same, played over and over. 

Diana Krall's Temptation from her single, USA pressed by Verve.


----------



## MagnusAtom (Oct 23, 2012)

Mic recording was done with Sine Sweep.


----------



## TheHammer (Dec 16, 2012)

Count me among those who believe that the difference between amps is inaudible. There are provisos: the amps have to have identical frequency response - and almost all transistor amps do, they have to be run below clipping, and they have to be at the same volume (apparently even 0.1 db is audible according to some reports).

When I focus on sound, it is speaker and speaker placement. I had a beloved pair of speakers and moved them from apartment, to house, to house and they sounded like a different pair of speakers each time I moved them.

However, there are differences between amps when it comes to features, inputs/outputs, power/headroom and (likely most important) auto speaker balance.

Now if I can just figure out which AV Receiver to purchase....


----------



## MagnusAtom (Oct 23, 2012)

TheHammer said:


> Count me among those who believe that the difference between amps is inaudible. There are provisos: the amps have to have identical frequency response - and almost all transistor amps do, they have to be run below clipping, and they have to be at the same volume (apparently even 0.1 db is audible according to some reports).
> 
> When I focus on sound, it is speaker and speaker placement. I had a beloved pair of speakers and moved them from apartment, to house, to house and they sounded like a different pair of speakers each time I moved them.
> 
> ...


You mean when you place two different branded amplifiers (other than those you can get within $5,000), change nothing but cables from one unit to the other, you cannot tell the difference? 
I'm likely to believe among the affordable top five avr brands will sound almost identical, if not identical... Not anything above. 

Looking at Harman Kardon's avr, transformer is so much bigger than say an onkyo. I think that will be different. Between the denon & marantz, perhaps similar. Put two amps in the room, you should hear a difference. If not, don't waste your time on spending extra $ on anything more expensive. 

I'm not against anyone's decision, whether they choose to be inclined any way. Based on experiments, they are different to my ears, and a number of my friend's. I do have a marantz sitting at home. And it sounds different from my McINTOSH, even when it's just driving my DIY mid range driver alone with overall spl being the same. 

Another point to note, you probably require more than what those avrs can do if you have 3-way floor standing speakers. Chances are, the avrs aren't going to deliver the full value of those speakers, because the impedances will vary from the nominal impedances, and hence, amps will be stressed especially when you turn them up to the vol you expect to hear in the cinema. A better amp will manage this better, and will give you a proper delivery of the speakers. 

It's also a good thing that differences cannot be heard in whatever set up you have. Save the $! 

I like the marantz sr7005. I think the sr7007 will be just as good with more features. 
Have you heard residential components now have Dolby Atmos ($15k and up for a processor)? In time to come these receivers should have those. Meantime, 4k passthru is the thing to look out for, I would suspect. Brave, and the hobbit were recorded in that format. 

Cheers.


----------

