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

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

    Votes: 139 48.6%
  • No... I do not believe there is any audibly significant difference.

    Votes: 147 51.4%

Can we really hear a difference between amps?

179K views 835 replies 96 participants last post by  jonathonsmith 
#1 ·
Can we really hear a difference between two amps?

More specifically... between two amps that have been level matched in a controlled listening test. We are not talking about amps that have been modified or are driven beyond their reasonable limits.

What a crazy and completely worn out question... I know, I know, but I figured why not have a bit of fun with it anyway.

Naturally our ZERO TOLERANCE FORUM RULES are going to apply as they ALWAYS do! So... if you are one of those who simply cannot have a sensible discussion on a hot and debated topic... STAY FAR AWAY from this thread. :D

Consider the following link and quoted articles:

LINK: Science and Subjectivism in Audio

Any amplifier, regardless of topology, can be treated as a “black box” for the purpose of listening comparisons. If amplifiers A and B both have flat frequency response, low noise floor, reasonably low distortion, high input impedance, low output impedance, and are not clipped, they will be indistinguishable in sound at matched levels no matter what’s inside them. Of course, some of the new “alphabet soup” topologies do not necessarily satisfy those conditions.

I really believe that all this soul-searching, wondering, questioning, agonizing about amplifiers is basically unproductive and would be much more rewarding if applied to loudspeakers instead. For various reasons that I have discussed in the past, people are more willing to change amplifiers than loudspeakers. That’s most unfortunate because a new and better loudspeaker will change your audio life but a new amplifier will not.

—Peter Aczel, Editor & Publisher, The Audio Critic
There has been a lot of hot chatter on the E-mail circuit over the past couple of months about the Steve Maki and Steve Zipser challenge in Miami. I thought you would appreciate a complete recount of the events. Zipser, a high-end salon owner, had issued a challenge that he would pay the airplane fare of any interested party who wanted to see him prove he could hear the differences between amplifiers.

On Sunday afternoon, August 25th, Maki and I arrived at Zipser's house, which is also Sunshine Stereo. Maki brought his own control unit, a Yamaha AX-700 100-watt integrated amplifier for the challenge. In a straight 10-trial hard-wired comparison, Zipser was only able to identify correctly 3 times out of 10 whether the Yamaha unit or his pair of Pass Laboratories Aleph 1.2 monoblock 200-watt amplifiers was powering his Duntech Marquis speakers. A Pass Labs preamplifier, Zip's personal wiring, and a full Audio Alchemy CD playback system completed the playback chain. No device except the Yamaha integrated amplifier was ever placed in the system. Maki inserted one or the other amplifier into the system and covered them with a thin black cloth to hide identities. Zipser used his own playback material and had as long as he wanted to decide which unit was driving the speakers.

I had matched the playback levels of the amplifiers to within 0.1 dB at 1 kHz, using the Yamaha balance and volume controls. Playback levels were adjusted with the system preamplifier by Zipser. I also determined that the two devices had frequency response differences of 0.4 dB at 16 kHz, but both were perfectly flat from 20 Hz to 8 kHz. In addition to me, Zipser, and Maki, one of Zip's friends, his wife, and another person unknown to me were sometimes in the room during the test, but no one was disruptive and conditions were perfectly quiet.

As far as I was concerned, the test was over. However, Zipser complained that he had stayed out late the night before and this reduced his sensitivity. At dinner, purchased by Zipser, we offered to give him another chance on Monday morning before our flight back North. On Monday at 9 a.m., I installed an ABX comparator in the system, complete with baling-wire lead to the Yamaha. Zipser improved his score to 5 out of 10. However, my switchpad did develop a hang-up problem, meaning that occasionally one had to verify the amplifier in the circuit with a visual confirmation of an LED. Zipser has claimed he scored better prior to the problem, but in fact he only scored 4 out of 6 before any difficulties occurred.

His wife also conducted a 16-trial ABX comparison, using a 30-second phrase of a particular CD for all the trials. In this sequence I sat next to her at the main listening position and performed all the amplifier switching functions according to her verbal commands. She scored 9 out of 16 correct. Later another of Zip's friends scored 4 out of 10 correct. All listening was done with single listeners.

In sum, no matter what you may have heard elsewhere, audio store owner Steve Zipser was unable to tell reliably, based on sound alone, when his $14,000 pair of class A monoblock amplifiers was replaced by a ten-year old Japanese integrated amplifier in his personal reference system, in his own listening room, using program material selected personally by him as being especially revealing of differences. He failed the test under hardwired no-switching conditions, as well as with a high-resolution fast-comparison switching mode. As I have said before, when the answers aren't shared in advance, "Amps Is Amps" even for the Goldenest of Ears.

Tom Nousaine
Cary, IL
Richard Clark $10,000 Amplifier Challenge FAQ

by Tom Morrow

Written 6/2006


The Richard Clark Amp Challenge is a listening test intended to show that as long as a modern audio amplifier is operated within its linear range (below clipping), the differences between amps are inaudible to the human ear. Because thousands of people have taken the test, the test is significant to the audiophile debate over audibility of amplifier differences. This document was written to summarize what the test is, and answer common questions about the test. Richard Clark was not involved in writing this document.

The challenge


Richard Clark is an audio professional. Like many audiophiles, he originally believed the magazines and marketing materials that different amplifier topologies and components colored the sound in unique, clearly audible ways. He later did experiments to quantify and qualify these effects, and was surprised to find them inaudible when volume and other factors were matched.

His challenge is an offer of $10,000 of his own money to anyone who could identify which of two amplifiers was which, by listening only, under a set of rules that he conceived to make sure they both measure “good enough” and are set up the same. Reports are that thousands of people have taken the test, and none has passed the test. Nobody has been able to show an audible difference between two amps under the test rules.
This article will attempt to summarize the important rules and ramifications of the test, but for clarity and brevity some uncontroversial, obvious, or inconsequential rules are left out of this article. The full rules, from which much of this article was derived, are available here and a collection of Richard's comments are available here.

Testing procedure


The testing uses an ABX test device where the listener can switch between hearing amplifier A, amplifier B, and a randomly generated amplifier X which is either A or B. The listener's job is to decide whether source X sounds like A or B. The listener inputs their guess into a computerized scoring system, and they go on to the next identification. The listener can control the volume, within the linear (non-clipped) range of the amps. The listener has full control over the CD player as well. The listener can take as long as they want to switch back and forth between A, B, and X at will.

Passing the test requires two sets of 12 correct identifications, for a total of 24 correct identifications. To speed things up, a preliminary round of 8 identifications, sometimes done without levels or other parameters perfectly matched, is a prerequisite.

Richard Clark normally has CD source, amplifiers, high quality home audio speakers, and listening environment set up in advance. But if the listener requests, they can substitute whatever source, source material, amplifiers, speakers (even headphones), and listening environment they prefer, within stipulated practical limits. The source material must be commercially available music, not test signals. Richard Clark stipulates that the amplifiers must be brand name, standard production, linear voltage amplifiers, and they must not fail (e.g. thermal shutdown) during the test.

Amplifier requirements


The amplifiers in the test must be operated within their linear power capacity. Power capacity is defined as clipping or 2% THD 20Hz to 10kHz, whichever is less. This means that if one amplifier has more power (Watts) than the other, the amplifiers will be judged within the power range of the least powerful amplifier.

The levels of both left and right channels will be adjusted to match to within .05 dB. Polarity of connections must be maintained so that the signal is not inverted. Left and Right cannot be reversed. Neither amplifier can exhibit excessive noise. Channel separation of the amps must be at least 30 dB from 20Hz to 20kHz.

All signal processing circuitry (e.g. bass boost, filters) must be turned off, and if the amplifier still exhibits nonlinear frequency response, an equalizer will be set by Richard Clark and inserted inline with one of the amps so that they both exhibit identical frequency response. The listener can choose which amplifier gets the equalizer.


FAQs:


How many people have taken the challenge?

Richard Clark says over a couple thousand people have taken the test, and nobody has passed. He used to do the test for large groups of people at various audio seminars, and didn't charge individuals to do the test, which accounted for the vast majority of the people who did the test. Around 1996 was the last of the big tests, and since then he has done the test for small numbers of people on request, for a charge ($200 for unaffiliated individuals, $500 for people representing companies).

When did the challenge start?


Sometime around the year 1990. Richard Clark says in a post on 7/2004 that the test with the $10,000 prize started about 15 years ago.

What were the results of the test?


Nobody has ever successfully passed the test. Richard Clark says that generally the number of correct responses was about the same as the number of incorrect responses, which would be consistent with random guessing. He says in large groups he never observed variation more than 51/49%, but for smaller groups it might vary as much as 60/40%. He doesn't keep detailed logs of the responses because he said they always show random responses.

Is two sets of 12 correct responses a stringent requirement?


Yes. Richard Clark intentionally made the requirements strict because with thousands of people taking the test, even random guessing would eventually cause someone to pass the test if the bar was set low. Since he is offering his own $10,000 to anyone who will pass the test, he wants to protect against the possibility of losing it to random guessing.

However, if the listener is willing to put up their own money for the test as a bet, he will lower the requirements from 12 correct down to as low as 6 correct.

Richard Clark has said “22 out of 24 would be statistically significant. In fact it would prove that the results were audible. Any AVERAGE score more than 65% would do so. But no one has even done that”.”

Do most commercially available amplifiers qualify for this test, even tube amplifiers and class D amplifiers?


Yes. Nearly all currently available amplifiers have specs better than what are required for the test. Tube amplifiers generally qualify, as do full range class D amplifiers. It is not clear whether Richard Clark would allow sub amplifiers with a limited frequency response.

Besides taking Richard Clark's word, how can the results of the test be verified?


Many car audio professionals have taken the test and/or witnessed the test being taken in audio seminars, so there isn't much doubt that the test actually existed and was taken by many people. One respected professional who has taken and witnessed the test is Mark Eldridge. Because the test has been discussed widely on audio internet forums, if there were people who passed the test it seems likely that we would have heard about it. Sometimes there are reports of people who believe they passed the test, but upon further examination it turns out that they only passed the preliminary round of 8 tests, where levels were not matched as closely as for the final test.

How can audio consumers use the results of this test?


When purchasing an amplifier, they can ignore the subjective sound quality claims of marketers. Many amplifier marketers will claim or imply that their amplifiers have some special topology, materials, or magic that makes the sound clearly superior to other amps at all volume levels. Many consumers pay several times more than they otherwise would for that intangible sound quality they think they are getting. This test indicates that the main determinant of sound quality is the amount of power the amplifier can deliver. When played at 150W, an expensive 100W measured amplifier will clip and sound worse than a cheap 200W measured amp.

Does this mean all amps sound the same in a normal install?


No. Richard Clark is very careful to say that amps usually do not sound the same in the real world. The gain setting of an amplifier can make huge differences in how an amplifier sounds, as can details like how crossovers or other filters are set. When played very loud (into clipping), the amplifier with more power will generally sound better than a lower powered amp.

Most people perceive slight differences in amplitude as quality differences rather than loudness. The louder component sounds “faster, more detailed, more full”, not just louder. This perceptual phenomenon is responsible for many people thinking they liked the sound of a component when really they just liked the way it was set up.

I changed amps in my system to another one with the same measured power and I hear a sound quality difference. Does this show that the test results are invalid?


No. Installing a new amplifier involves setting the gains and crossovers, and any slight change you make to those settings is going to affect how things sound.

Is adding an equalizer just a way of “dumbing down” the better amplifier ?


Richard Clark allows the equalizer to be added to whichever amplifier the listener wants. It can be added to the amplifier that the listener perceives as the weaker amplifier . The EQ is most likely to be used when comparing a tube amplifier (which exhibits slight high frequency rolloff) to a solid state amplifier . In that case Richard Clark says he can usually fashion an equalizer out of just a resistor and/or capacitor which for just a few dollars makes the solid state amplifier exhibit the same rolloff as the tube amplifier, and therefore sound the same. If the tube amplifier really sounded better, then modifying the solid state amplifier to sound indistinguishable from it for a few bucks should be a great improvement.

How might allowing clipping in the test affect the results?


It's impossible to know for sure because that would be a different test that has not been done. But Richard Clark seems to think that in clipping, conventional amplifiers would sound about the same, and tube amplifiers would sound different from solid state amplifiers.

Richard Clark reported that he did some preliminary experiments to determine how clipping sounds on different amplifiers . He recorded the amplifier output using special equipment at clipping, 12db over clipping, 18db over clipping, and 24db over clipping. Then he normalized the levels and listened. His perception was that with the same amount of overdrive, the conventional amplifiers sounded the same. With the same amount of overdrive the tube amplifiers sounded worse than the conventional amplifiers . On the basis of that experiment, he said “I believe I am willing to modify my amplifier challenge to allow any amount of clipping as long as the amplifiers have power ratings (actual not advertised) within 10% of each other. This would have to exclude tube amplifiers as they seem to sound much worse and it is obvious”.

If a manufacturer reports false power ratings, will that interfere with the test?


No. The test is based on measured power, not rated power .

Does this mean that there is no audible difference between sources, or between speakers?


No. There are listening tests that show small but significant differences among some sources (for instance early CD players versus modern CD players). And speakers typically have 25% or more harmonic distortion. Most everyone agrees that differences among speakers are audible.

Does the phrase "a watt is a watt" convey what this test is about?


Not quite but close. Richard Clark has stated that some amplifiers (such as tubes) have nonlinear frequency response, so a watt from them would not be the same as a watt from an amplifier with flat frequency response.

Do the results indicate I should buy the cheapest amp?


No. You should buy the best amplifier for your purpose. Some of the factors to consider are: reliability, build quality, cooling performance, flexibility, quality of mechanical connections, reputation of manufacturer, special features, size, weight, aesthetics, and cost. Buying the cheapest amplifier will likely get you an unreliable amplifier that is difficult to use and might not have the needed features. The only factor that this test indicates you can ignore is sound quality below clipping.

If you have a choice between a well built reliable low cost amp, and an expensive amplifier that isn't reliable but has a better reputation for sound quality, it can be inferred from this test that you would get more sound for your money by choosing the former.

Do home audio amps qualify for the test?


Yes. In the 2005 version of the test rules, Richard explicitly allows 120V amplifiers in a note at the end.

How can people take the test?


They should contact Richard Clark for the details. As of 2006 Richard Clark is reported to not have a public email account, and David Navone handles technical inquiries for him. Most likely they will need to pay a testing fee and get themselves to his east coast facility.

Is this test still ongoing?


As of early 2006 , there have not been any recent reports of people taking the test, but it appears to still be open to people who take the initiative to get tested.

Do the results prove inaudibility of amplifier differences below clipping?


It's impossible to scientifically prove the lack of something. You cannot prove that there is no Bigfoot monster, because no matter how hard you look, it is always possible that Bigfoot is in the place you didn't look. Similarly, there could always be a amplifier combination or listener for which the test would show an audible difference. So from a scientific point of view, the word “prove” should not be used in reference to the results of this test.

What the test does do is give a degree of certainty that such an audible difference does not exist.

What do people who disagree with the test say?


Some objections that have been raised about the test:

  • Richard Clark has a strong opinion on this issue and therefore might bias his reports.
  • In the real world people use amps in the clipping zone, and the test does not cover that situation.
  • Some audible artifacts are undetectable individually, but when combined with other artifacts they may become audible as a whole. For instance cutting a single graphic EQ level by one db may not be audible, but cutting lots of different EQ levels by the same amount may be audible. Maybe the amps have defects that are only audible when combined with the defects from a particular source, speaker, or system.
  • Some listeners feel that they can't relax enough to notice subtle differences when they have to make a large number of choices such as in this test.
  • There is a lack of organized results. Richard Clark only reports his general impressions of the results, but did not keep track of all the scores. He does not know exactly how many people have taken the test, or how many of the people scored “better than average”.
  • If someone scored significantly better than average, which might mean that they heard audible differences, it is not clear whether Richard Clark followed up and repeated the test enough times with them to verify that the score was not statistically significant.
Is there one sentence that can describe what the test is designed to show?

When compared evenly, the sonic differences between amplifiers operated below clipping are below the audible threshold of human hearing.

Links


Note from the author

I wrote this Summary/FAQ because I found that many of the people who disagreed with Richard Clark about the challenge simply didn't have the whole story on the challenge. I originally thought the challenge was flawed even after I read the rules a few times, but after reading lots of comments from Richard Clark, my objections were answered and now I believe that understanding the challenge is a very useful tool for learning what is audible and what isn't. I have no relationship with Richard Clark and have never communicated with him except that I've read his public postings about the challenge. If anyone finds typos or factual errors in this document please contact me.
I have leaned towards the camp of not being able to hear any significant difference between almost any two amps out there when played at moderate levels on the typical speaker system, unless there is something wrong with one or the other amp that might cause it to color the sound.

Granted... a low-end receiver may well have an issue driving a system of certain electrostatic speakers... or speakers with low sensitivity, especially if pushed to higher levels. There are going to be exceptions, but for the sake of this discussion, let's say we are using a pair of Klipsch RF-62 II speakers with a sensitivity of 97dB @ 2.83V / 1m ... or perhaps the Duntech Marquis speakers that Zipser was using above at 92db.

I have owned processor/amp combos and/or receivers from Sony, Denon, Sunfire, McIntosh, Adcom, NAD, Onkyo, Earthquake, Anthem, Rotel, Lexicon, Emotiva (and probably others I cannot remember) powering Snell B-Minors, Klipsh Forte, PSB Image, SVS, JBL, Boston Acoustics, VMPS RM30's, MartinLogan Ascents, ML Spires and recently the older ML Prodigy mains with a Theater center and Ascent surrounds powered by Emotiva XPA-1's and an Onkyo 906 Receiver. Currently (updated January 2104) I run an Onkyo 5509 with an Emotiva XPR-5 with MartinLogan Montis, Stage X and Motion 12's. The most significant difference I ever heard was moving to the Martin Logan speakers. NOTHING had EVER made anywhere close to a difference in sound as did the MartinLogan speakers. I thought at one time that my NAD receiver had more of a soft sound (maybe "warmer" as some will state the description), but was told (never did verify it with NAD or via measurements) that NAD intentionally setup their receivers with a rolled off high-end. However, I have heard significant differences in speakers. I have also performed A/B testing between several amps and have not found any differences outside of clipping and/or distortion.

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

Your thoughts and comments will be interesting.
 
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#387 · (Edited)
edit - I accidentally identified an Apogee Studio Grand as a Martin Logan. It was 20 years ago, but I remembered what they looked like, did a Google image search...

Hah, good enough for Fabio is good enough for me! Time to go to Manhattan and look for some used fpb 600s at the second-hand stereo shops, lol. In fact it was listening to a Krell powered system when I first realized that the ultra-high-end employed a fair bit of smoke and mirrors. I was listening to Apogee/Krell and I mentioned that a bassline from a Sly & Robbie track was missing the lowest octave. He responded 'if this system isn't reproducing the bass, it doesn't exist. It must have been imaginary bass'. Today I can play reference flat to 10hz and I can say in no uncertain terms - the bass was not imaginary. Of course the system I had back then (1991) was also capable of reproducing said 'imaginary bass'. That's the day my wish to own Krell died a quiet death.

I'm not saying that the Krell/Apogee system couldn't do the trick. On that day, the setup was less impressive than my own well tuned, less expensive rig.

So, armed with the knowledge gained from the discussion in this thread, I re-arranged my system at least two dozen times yesterday - genuine obsessive tear apart and rearrange behavior.

The end result is that the Crown XTi-1000 is back online, driving my L/R mains. If not for this thread, I would have retired it, thinking it to be flawed. It is sensitive to noise interference, enough that stray electrical noise was polluting the highs... but that was only partly the amps fault. Treating the room also means making sure there is as little interference as possible. Having fully isolated the AVR from any conductive interconnects, and having gone through the whole feed for my cable line tightening connections, I achieved a really low noise floor and whatever was affecting the highs is gone. Since I have two identical pairs of the same speakers up front, A/B testing is a piece of cake. There's no way I'd be able to pick the Pioneer Elite AVR vs. the Crown XTi-1000 in DB tests. I am thrilled with the extra headroom (+3db) the Crown buys me - and the extra power the AVR gets for the rest of the channels - it is a genuine qualitative improvement.
 
#389 ·
I was listening to Martin Logan/Krell and I mentioned that a bassline from a Sly & Robbie track was missing the lowest octave. He responded 'if this system isn't reproducing the bass, it doesn't exist. It must have been imaginary bass'. Today I can play reference flat to 10hz and I can say in no uncertain terms - the bass was not imaginary. Of course the system I had back then (1991) was also capable of reproducing said 'imaginary bass'. That's the day my wish to own Krell died a quiet death.
I handily doubt the Krell was the issue here as I am pretty sure back then they were all class A amps and would go to almost DC as directed. I am not sure the ML would hit anything near that low albiet with a completely down point below say 20 hz. Intersting to note that in the interview with Carver online, he was the first to be asked to make a system inclusive of subwoofer that could not only replicate an earthquake but the sound of a jet airplane as well. As such, he did create a system that could replicate the 140 db needed for a jet engine as well as the 7 hz noise needed to replicate an earthquake. He had to cheat to get notes that low so in doing he used hyrdaulics to move the speakers in and out as slow as needed. Quite an ingenius man.

Now I am not a big Carver fan, never have owned anything he made but in watching the video and doing some online research, I find him quite the interesting gent, a physists, an engineer and an audio manufacturer and I have none of the talen to do any of that...what a bummer. :huh:
 
#388 ·
Well Mr. King, that is incredibly cool actually. The discussion has caused you to get a bit closer to your system and what it will reproduce, and it appears improvements have occured that will allow you to listen more. I am happy to know that.

In follow up to the remainder of the discussion, I realize I will not change anyones mind, without proof it is not going to happen and that makes sense...why would my rantings make any difference is quite realistic. But as mentioned above, if someone can get something out of a discussion that improves what he has in house, then some good has come of all this. I did come across a bit of new information that I did not know and has apparently been put aside with age. In watching some online interviews with Bob and also Nouisane there was a test done by The Audio Critic as a blind test between the Carver amps and as SS Levinson amp. It also ended in a cannot tell the difference, but with The Audio Critic that seems to be what everyone would more or less expect. Black box and blind testing was done and here is a description I found online that shows, Carver did manage to make it work.

Carver caused a stir in the industry in the mid-1980s when he challenged two high-end audio magazines to give him any audio amplifier at any price, and he’d duplicate its sound in one of his lower cost (and usually much more powerful) designs. Two magazines accepted the challenge.
First, The Audio Critic chose a Mark Levinson ML-2 which Bob acoustically copied (transfer function duplication) and sold as his M1.5t amplifier (the “t” stood for transfer function modified).
In 1985, Stereophile magazine challenged Bob to copy a Conrad-Johnson Premier Five (the make and model was not named then, but revealed later) amplifier at their offices in New Mexico within 48 hours


I really do not like that he sold his stuff once he copied the amps, however, in reality he could have done that from his facility in Washington without the challenge...so that seems a moot issue.
 
#392 ·
Carver caused a stir in the industry in the mid-1980s when he challenged two high-end audio magazines to give him any audio amplifier at any price, and he’d duplicate its sound in one of his lower cost (and usually much more powerful) designs. Two magazines accepted the challenge.
First, The Audio Critic chose a Mark Levinson ML-2 which Bob acoustically copied (transfer function duplication) and sold as his M1.5t amplifier (the “t” stood for transfer function modified).
In 1985, Stereophile magazine challenged Bob to copy a Conrad-Johnson Premier Five (the make and model was not named then, but revealed later) amplifier at their offices in New Mexico within 48 hours
(of note: no testing was done blind in that case).

What carver did was invert one amp and then sum the signal (with false identical loads). He got the summed signal to flat (within -70db) by modifying his amp (supposedly: this was all behind closed doors).

The first time they listened, they though there were differences. The second time, they thought more differences. The third time they could not tell them apart.

Which is confusing because I'm not aware that it would be possible to make any changes after the first set based on the testing method used to conform the changes in the first place. -70 is -70. Perhaps there's more he didn't tell, but since that testing was the point he was trying to prove...
 
#399 · (Edited)
The only time amps sonic signatures differ from one another is when they are being pushed well beyond their output capabilities. If the power draw is well within the weakest amp in a comparison, then there will be no audable differences. I am assuming competently designed amps whichh would exclude boom boxes and things of that ilk.
 
#404 ·
Considering the fact our eyes can be fooled this easily:



It's not a surprise one can also fool the ears with ease.
 
#406 · (Edited)
But is it fooled into believing there is a difference or there isn't ? :ponder: :D

I can't this debate is still going on, there is no right or wrong answer that anyone on either side of the argument will agree on. I am dizzy from running around in circles :run2::run::sick:
 
#414 ·
It's entirely in the shading and how your eye compensates. You've seen the illusion with the black and white grid, where phantom gray dots appear - that's what's going on. The green has nothing to do with it.

 
#416 ·
So amps do sound differently because of shading? :D J/K

With so much affecting the signal chain and purist always wanting to limit what goes in the signal chain I would have to agree that some amps can change the sound of any original input signal.

I am dizzy now from all this foolish imagery.:rofl:
 
#417 · (Edited)
Suffice to say, the method by which one's brain takes what's coming in through the ears as cobbles together the illusion that there is a musician standing in the space between their two speakers is dependent on a similar mechanism.

For the sake of sticking with sound, here' the 'Shepard Tone' audio illusion - the 'endless gliss'

http://youtu.be/iupWWsh8YCo

So amps do sound differently because of shading? :D J/K

With so much affecting the signal chain and purist always wanting to limit what goes in the signal chain I would have to agree that some amps can change the sound of any original input signal.

I am dizzy now from all this foolish imagery.:rofl:
 
#418 ·
I was not able to grasp the thought of imaging early on in my quest for sound that brought me closer to the music, performers and what was trying to be reproduced. I now very much believe in imaging, the formation of a volatile sound space between, behind and outside of the speaker plane.
The down side of knowing this is available but some pieces of equipment will not replicate the illusion. That has allowed me to on occasion easily know that some amps do not reproduce this as easily as others. And no it is not indigenous to amp, cd players, dacs, preamps and some speakers can drain the sound space from the room in a heartbeat.
 
#420 ·
:unbelievable:

I find it odd that people place imaging qualities on their electronics and not so much on speakers/room acoustics where it should be. If the imaging is poor, change out the speakers, fix the acoustic space the speakers are located in before driving over the electronics cliff of no value added.
 
#419 ·
My quest for finally hearing a "live recording," sound like a live recording was when I heard a Yamaha baby grand piano connected to one of ML's bigger ESL speakers. It was playing a SACD with classical jazz. Was just amazing. Unfortunately that is only one particular genre.

I like the fact that I could build my own amplifier, tone characteristic and all built in. But with all the music I listen to and so much of the music industry being electronic instruments I am liking the pro audio amps consistency of sounding similar.
 
#422 ·
I have to admit to ignorance in this case, I have used pro amps when playing in the band, I have a big ole pro amp in the garage wrapped up, but have never used on or heard one in a home stereo.

I know I know, but I always had a mind set that they were not up to home audio standards in way of sonic attributes. Me thinks I may have to get some adapters and try this out one day, although that could shatter a long held belief. Oh the horror......:yikes:
 
#421 ·
Maybe I was not clear and frankly that seems to be happening a lot these days. Yes Speakers must be able to do this first and foremost and they have the largest portion of the responsibility in the creation of the soundspace. However, what I mean to say is that other components in the chain of reproduction, including the original medium be it cd, vinyl, tape of computer. Each piece has to work together to make this happen. When it works, dang it is a very nice experience for a 2 channel stereo.
 
#423 ·
Jack - you have been holding out on us. Sounds like you may have everything you need to conduct your own blind A/B testing. Just enlist a friend to do the swaps or get a simple A/B switch. I would volunteer but fear I have eliminated myself from the possible pool of candidates. :)
 
#425 ·
Not sure it will do me any good as I just opened the bubble wrap and it is a Peavey 2.6C and the front panel is stamped with 130 Watts per channel in stereo, which is much less than the Emo's in the system now. None the less, it cant hurt to get the proper adapters and float it in the system one day soon. I could pull the B&W's out of storage and move the Martin Logans aside for a night. Could be fun to just mess with stuff.
 
#426 ·
Either way you never know until you try. I dont think anyone should go out and buy a power amp just to try it. Just use what you can and see if you like is all. Then you can A/B the amplifiers to see which amps tone you like. :D
 
#427 ·
I voted yes but I dont neccesarily believe that it is a "significant" different. In my studies of amplifier design which I have been doing in my free time there has been much discussion in my books about 2nd and 3rd order Harmonic Distortion and how the 2nd order sounds more pleasing to us than 3rd order distortion.

Because of this I believe it is possible that you can hear a difference as a amplifier of 2nd order harmonic distorition of say 10%(I know this is really high) compared to one with 10% of 3rd order distortion...the majority would take the former as their choice.

Now I know some of you will bring tube amps up because they have a higher 2nd order distortion and I think that is why so many find them to sound more musical, but with the problem of Intermodular Distortion I do not believe that they will work in the majority of situations. I also find them to be a bit finnicky. I have a Bottlehead Quickie in my office and think it sounds great going to the amp and speakers....but the tubes in the Quickie are infrasonic which can be annoying and having to replace tubes with "matched" pairs gets pricey.


So I think in my amplifier studies I am going to focus more on Mosfet designs than anything else.
 
#429 ·
Validity of a test is whether it tests what is intended. Whether results are convincing or not depends upon how you define your statistical test and how you interpret the results. There are well established statistical means to determine whether a result represents a better than chance outcome and depends upon the number of choices and the number of trials.
 
#433 ·
Im still here but have not had time nor inclination to do any swap outs. My wife has been quite ill and she takes first place for time of course. Hopefully this week I will be able to mess around.
 
#434 ·
Indeed. Best wishes to your wife for a speedy recovery.
 
#436 ·
Health is a precious gift, equal only to being loved or being with somebody you love...
Best Wishes and a speedy recovery.

I've found a simple remedy, "Rescue Remedy" has an alopathic ingredient of zinc and several homeopathic ingredients that help knock down first signs of cold or flu symptoms and also support the immune system for a faster recovery. Use this especially at first signs of cold or flue and use sparingly but daily during a cold or flu. Everybody is different but for me colds last 3-4 days and are never severe. I cannot remember when I've had a cold or flu. It was at least before collage in 92'

Regards
 
#437 ·
Thank You gentlemen and y'all are of course correct. When loved ones are ill it shines a bright light on what is truly important in life. Thanks Greg for the advice but it is not the flu she suffers from, she has Crohns and had to have several feet of her intestines removed a good many years ago. Well this disease never quite goes away and the Sunday before last it came back with a vengeance. She is home now trying to recuperate for a bit so she can go back to the hospital and have some additional surgery.

Yes I am being a good boy for once and playing her plenty of music, and truth be told, she does not give a wit about the equipment being used, she likes the sound and that is cool. I have tried to break her in to the constant frustration of upgrades and change outs and she more or less shakes her head and gives me THAT look. :blink:
 
#438 ·
Ok everyone that has been holding their breath can now let the bad air out and take in some fresh breaths I have done my comparison and the results are not surprising but....and this is a big question, did my initial biases that I of course do not have, influence the results ? I am not sure but I did give this a good go. Inserting the Peavey into the system was fun and a neat romp with different electronics. I did not think the Peavey sounded as good as the Emo and just did not have the same sense of drive. The pro amp just sounded somewhat less authoritative and less colorful if you will. I was just not drawn into the music in as positive a way when the Pro amp was involved. Now please note this could be due in part to the adapters that have to be inserted and the fact that the Pro was much less powerful I am just not sure, so it is quite possible they were not playing on a level field, but as it was the only Pro amp in the house, it was worth a try. Could I live with the Pro amp, yep, but I would not wish to replace anything with it at this time.
What does this mean ?? I really do not think it means a whole lot because of the differences in everything surrounding the test. It was, I have to admit, much less of a difference than I anticipated and that thought alone causes me to explore further.
 
#439 ·
My sister has crohns for 25 plus years so my prayers for both of you. Back to the amp question.One guy was right, speakers are the limiting factor , room treatment is second most important. But matching the right amp to the speakers is very important. Over my 35 years of careful listening (my system and a handful of other peoples) I have heard many tube amps which blended well with the speakers. Highend class "A" amps have done a wonderful job with the right speakers several times. Back in the early 80's there was a cheap $200 NAD intergrated amp that many people wanted for the pre-amp section which drove small speakers really well. So find the right combo , its not just spend as much as you can. Good luck , oh yea amps sound different ,listen more- its for fun......
 
#440 ·
Best I can recall, back in the early '80s my Technics receiver did just fine running a pair of EPIs. Honestly, by the time 1980 rolled around, I already was an "audio atheist". I still believed the hype about amps sounding different, but now that I'm a grown up I know the difference between fantasy and reality. If an amp is solid state and features typical FR and THD numbers, then it sounds the same as the next amp, so on and so forth. As has been discussed already, tube amps add distortion to the signal, which amounts to a 'signature sound'... so of course tube amps do sound different from each other, and different from solid state amps.
 
#441 ·
Amps will be sonically indistinguishable if the follow caveats are met:

- the load presented to the amps is well within the intended design paramaters of the amps
- the same load is used to test among the amps
- the room acoustics are identical and speaker/lietener position remains identical through out the tests.
- listening tests are conducted as Single Blind Listening tests. Doesn't have to be double blind tests.
 
#442 ·
Might I suggest subscribing to the Paul McGowen news letter, he of PS Audio. He is quite clear that different topologies sound different and has proven it over the years. Interesting reading. I think that most designers do the same thing. One can find many discussions from the designers about how and why they use certain products to tailor the sound of their products. Having not designed one before I can only say that different types of components imo do sound differently. In building speakers I find that using better components in the crossover certainly did change the sound, ergo, they should do the same in any electrical component that is manipulating sound/electricity.
 
#445 · (Edited by Moderator)
Paul has issued a series of articles that start from design to execution of many different components and he seems to be quite adept at what he is doing, Personally I do not take stock in blind testing as it really limits our acclimation to products that may or may not be closely familiar to us. I do understand than half the folks polled hear no difference and that is quite important. But maybe if the have that cannot hear the difference would spend more time with the products they may. Who knows. I do believe that differences have to be there if for no other reason than so many different components are used.
http://www.psaudio.com/product-page/

When you reference articles without links it really takes away the credibility of the reference.
PS Audio does not even sell amplifiers.
And of course you take no stock in blind tests because the results always discount your position.
 
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