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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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#200 ·
I always just go back to the proof (see the first post) and that is the difference we are referencing for this thread. I think we can always come up with certain circumstances where one amp may outperform another in some way, but in a comparison like the first post, I think we don't have much choice but to come away with what that comparison proved... until someone proves otherwise with an acceptable testing method.
 
#202 ·
I dunno, to me this seems like a counter argument. If we cannot measure it, it cannot be real. That is a bit like happiness or sadness, hope or doubt, if we cannot measure those things how does one quantify them ? Can we measure how much soundstage an amp will produce ? How deep or wide will the sound be ? And no we are not changing anything else but amps in this thought process. How about dynamics, I understand that the Class D amps have tremendous power for the bottom end of a speaker system as there is so little power wasted in the transfer but the top end is not quite as nice. There are differences all over, to deny them because we cannot measure them...today anyway, is probably not correct.
 
#204 ·
I am sorry but there is no bias here on my part. I really have never cared about cost vs performance.
I have heard some costly amps that just did not sound good. The Audio Research D100 being a very good example. There are a good number of quite expensive amps out there that just do not sound right, while at the same time there are a plethora of inexpensive amps that sound wonderful, remember the NAD3020, that thing got the soul of the music right.
The differences may be subtle and take time to show themselves, but they are there if one listens.

As one great mind said, Not everything that can be counted counts, and not everything that counts can be counted.
 
#205 ·
Not sure how to respond in the poll.

I believe all amps sound the same but... I believe if you are comparing 2 dif amps that you can hear a dif due to capacitance, resistance of wires and also inputs and output not compatible.

Example... Years ago I had a Audible Illusions preamp and a Classe DR10 amp.. I could swap speaker wires, interconnects, dampening mats etc and hear a night and day dif. When I inserted a Classe 6 preamp into the mix none of the above made a dif at all. I had read and I am a firm believer of the output of the preamp and the input of the power amp being matched or you will be subject to audible dif in cables. When i look for a power amp I want a input impedance that is as low as possible to negate audible cable dif.
 
#207 · (Edited)
I was fortunate to be able to participate in and setup some very interesting blind comparisons back in the late 80's, early 90's. It all began when I wanted to put my hard earned cash down on a certain Harman Kardon amplifier and was chastised for even suggesting this. Why would I want to waste my money when I had the ability to score custom hand built mono-blocks at cost? Well, the reason was simple, the H/K at cost was about $600. The custom mono's were still $5K apiece. We setup the test and not a single person in the group including the resident golden ears could do better than 50/50. Case closed and my stance has remained ever since.

Of course there were still several skeptics that participated in the experiment and came up with many reasons why the test was not valid. So, over the course of several weeks I took every opportunity to stealthily disguise my lowly amp by placing it another room and leaving the very pricey amplifiers in full view. It was amazing how many incredible compliments the H/K then received from these same skeptics. Velvety, finely textured, revealing of every last musical nuance......... We are after all human and we often hear what our brains tell us we are hearing.

Does it matter that you can hear a difference between amplifiers? Of course it does. That is one of the most entertaining parts of this hobby and the single largest reason we have so many options to choose from. I love this hobby. :)
 
#209 ·
So, over the course of several weeks I took every opportunity to stealthily disguise my lowly amp by placing it another room and leaving the very pricey amplifiers in full view. It was amazing how many incredible compliments the H/K then received from these same skeptics. Velvety, finely textured, revealing of every last musical nuance......... We are after all human and we often hear what our brains tell us we are hearing.
That ain't even right... but I got a great chuckle out of it (more than once). :D

Velvety? Seriously? Someone has really created this term to describe a sound and there are others who can actually hear it too? :rolleyesno: Don't get me wrong... there are terms I have heard numerous times that I can somewhat relate to, such as warm, laid back, harsh, etc... (more simplified I guess), but velvety, finely textured must be terribly unique to only the golden eared folk... and apparently fictitious according to your sneaky little test.
 
#210 ·
Indeed I have read the article, have read much of Tom and Peter's writings over the years and and fully disagree with their findings. I do not think I have much of a bias, maybe I do, but having heard differences, I have to go with that....and yet to think that those two gents who reportedly cannot hear a difference between amplifiers are paid reviewers and both have megabuck amplification systems.
I find the information that they do not practice what they preach seems well odd.
Lets just say I am with the percentage of folks on here that can hear a difference.
 
#212 ·
Indeed I have read the article, have read much of Tom and Peter's writings over the years and and fully disagree with their findings.
So you fully disagree that those people could not hear a difference, even though they admitted they could not hear the difference? :scratch:


This is good too, 45% of the folks that voted can hear the differences and yet they get the roll eyes.
Hmm. You win.
The roll eyes are for those using the particular term mentioned (velvety). FOR THE RECORD... I have NOT rolled my eyes at the 45% who claim they can hear a difference and I NEVER indicated such. It is amazing how someone can twist around what someone has said to try to make it suggest something else. I should give that a roll eyes... but I'll give you a wink instead. ;)

I agree that 45% "think" they hear a difference... and some may have actually heard a difference at some point in time because of abnormal circumstances and it was NOT under the same type testing as in the first post. I suspect if these 45% setup the same test comparison as in the first post that the percentage would drop... probably to about 0%.

Did I still win? :R
 
#215 ·
Of course you win Sonny, you have more posts and those with the most posts wins... :)

Although, I have seen Pink Floyd in person for the road shows of Dark Side of the Moon, Wish You Were Here, Animals, A Momentary Lapse of Reason not to mention Roger Waters on his own 3 times in addition to the above. Can I win something too ???

It is my sincere belief that I hear a difference, albeit I have not participated in a short term blind test. However 45% is a pretty big number and maybe one day we shall overcome, oh I hear a song in there.
I dont think that the posters are lying necessarily, however, those truths they espouse are also biases. Maybe they have a preconceived notion that there are no differences, so they hear none. I really hesitate to say anything bad, I just know I have heard the velvety, silky melt in your mouth chocolate covered mint sounds coming from some amps and ground peppered tapioca pudding from others. :innocent: Or not...Ok I never heard velvet but I have felt it once in a store...or was it in a Chrysler, not sure now.


I do draw the line at some claims in way of top secret nonsense names for cables, interconnects and some of the other stuff on the market that does seem to be snake oil. Having said that, I must confess that there is a bias in that statement mainly because I have not heard the end of the earth differences in some of these things being reviewed. I guess if I ever win a bazillion dollars in the lotto I will give them a try and maybe they will make a believer out of me...as soon as one of those super clocks gets all the bad juju from my room for only $19.95.
 
#217 ·
Although, I have seen Pink Floyd in person for the road shows of Dark Side of the Moon, Wish You Were Here, Animals, A Momentary Lapse of Reason not to mention Roger Waters on his own 3 times in addition to the above. Can I win something too ???
You have already won if you have been all there and done all that. I definitely can't touch that... wish I could, but all I can muster up is one concert on the Pink Floyd Division Bell Tour.

I dont think that the posters are lying necessarily, however, those truths they espouse are also biases. Maybe they have a preconceived notion that there are no differences, so they hear none.
Keep in mind that Steve Zipser owned Sunshine Stereo, who sold very high end equipment. He had preconceived notions that he COULD hear a difference, until Tom came along and proved to him he could not. I can tell you that I would definitely want to hear a difference between a pair of $14,000 Class A monoblocks and a cheap $200 integrated amplifier, but he, his wife... nor any of his friends could hear a difference. Yet, we all know full well there was truly a difference in the amps... it was $13,800... and the Alephs looked prettier. :bigsmile:

I do draw the line at some claims in way of top secret nonsense names for cables, interconnects and some of the other stuff on the market that does seem to be snake oil. Having said that, I must confess that there is a bias in that statement mainly because I have not heard the end of the earth differences in some of these things being reviewed.
I am not going to say I will never be able to hear a difference in amps, cables or whatever, because I may get that opportunity to participate in a DBT one day and actually hear a difference. I think I have heard differences in the past between products, but those difference could be attributed to so many different variables and the differences were not determined under any type of organized testing setup. I do have a difficult time believing the differences some people claim, but that does not mean they are wrong or that it is not true, it just means I have a hard time believing it... to a point I occasionally poke fun at the thought. I think I am biased by what has been proven to me through tests that I have read about at this point, which I have zero problem admitting. It is what it is.

I guess if I ever win a bazillion dollars in the lotto I will give them a try and maybe they will make a believer out of me...as soon as one of those super clocks gets all the bad juju from my room for only $19.95.
I won't ever win a lottery because I won't be buying a ticket, but if I ever did come into a lot of money where I could spend it like there is no tomorrow :spend: ... I am sure I would search out the best looking amps around and pay whatever the price would be, but in searching for the absolute best sound I would be more concerned about what speakers to buy... which is what has made the most dramatic improvement for me.



I like to use the descriptive term "Velveeta" when I feel an amp sounds cheesy to me.....is that OK :huh: :bigsmile:
Absolutely, but you gotta tell us what cheesy sounds like. Does it sound like it has holes in it? :nerd:
 
#218 ·
Yep I realize those guys have heard some of the biggest and best and that is what makes this all so difficult to rationalize. All these years I have listened intently and believed to the core I could hear differences. (Dont tell anyone but I thought I heard cable differences as well) If there are no audible difference this would cause a personal global re-think on my part. I no longer have access to a number of components so it may be awhile before I do any comparative listening again, but when I was in Savannah and Chicago, I brought home so many things and was very familiar with the listening systems qualities or lack thereof.

So for now I will stick to my beliefs until proven wrong to my satisfaction, which if done I will readily admit to. Jack is now open minded. Or maybe I do have holes in my head from the cheese factor, :blink:

Yes, I was a Floyd nut and did attend all of those concerts live. No other band even came close to the stunning performances and sound of that band and their members. I remember seeing Animals in Chicago at Soldier Field and when the band got quiet, you could hear a pin drop the audience was soooo hypnotized. Stunning.

I will spend the long weekend listening, and YES speakers make the biggest difference, and will try to determine if I can repeat changes in sound from swapping out other components. This should be enlightening

I do have zillions of cables, several Dacs, SS and Tube, SACD players music files so if you ever need a good Blind test no problems there. Most importantly I have a door on the room, keep the pets out.
Lastly...I dont buy Lotto either, guess that makes it a bit hard to win. I suppose if I knew the money actually went to some good, schools, poiice, libraries, music programs etc, I may buy a few. At this time I dont wish to fatten the political wallet anymore than it is, but that is another discussion.
 
#219 ·
Some amps will definitely add an audible sound to your playback system. I've got a headphone amp that distorts on low impedance headphones, I've got my Emotiva that has an audible hum when all is silent(from my listening position, my tube amp has it's own unique character, and my t-amp has a treble boost with certain speakers and doesn't have deep bass(iow, it's an EQ as well lol).

So amps can make a difference if they are not as well designed--or designed to be inaccurate.
 
#222 ·
No disagreement with any of these situations but what you are describing are differences in sound when an amp is driven beyond it's design capability. Or in the case of the Emo amp it is low level noise which could be introduced via a grounding problem, cabling or inherent to the amp itself. In most cases this type of low level noise almost always changes very little in amplitude compared to the input signal. So when driving an input signal to normal listening levels the noise is buried and usually inaudible (although many will claim to hear this low level noise as well). There have been several tests regarding low level noise audibility over the years. Specifically when comparing ADC's and DAC's quantifying their performance based on noise floor and resolution. Again complete level matched blind testing is the only way to completely eliminate any bias.

I think everyone understands that tube amps add distortion to the input signal. Some people obviously enjoy this distortion and prefer it over solid state amplification which in almost all cases today is distortion free regardless of the design. The important thing is to use any amplifier within the parameters it was designed to operate. This is critical to understanding why the results of these types of tests are always the same.
 
#220 ·
There see, more positive proof, Dan knows that differences exist. Its a natural think, like gravy on taters or chicken gravy on a fried steak...whatever that is.

Anyway there are so many opinions for and against, some of us have to hold our ground. :T
 
#221 ·
No one has said that differences do not exist between two amps under the circumstances he referred to.

From the original post:

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.

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.
 
#225 ·
Good Number of qualifiers in that statement and a nice "Granted there are going to be exceptions"
Oh and a good one.." 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 blah blah blah.

Not gonna change my mind, i CAN hear the differences between SOME amps blah blah blah. We are saying the same thing only different. Y'all will read it to fit a certain belief as will I.

Life is good when we have choices. Besides there literally has to be sonic differences as they are oft times constructed so differently, the ODDS are on my side.
 
#224 ·
Good question Jerry and no, you know I really did not see them, but they sure did sound good. I hope they used all the same amps so one side of the audience did not hear something different than the other side. Actually, they were all in surround sound, even DSOTM. Good stuff
 
#226 ·
Hey... not the first person that I know of is trying to get you to change your mind. A man's opinion changed against his will is of the same opinion still. Yet, it would be very interesting to see your response in a DBT as was conducted in the first post. :gulp:

We have always been talking about the typical norm, not the rare exceptions. I think everything you have brought up has not given any consideration to the first post, which is what the jest of the thread is about and why I keep pointing back to it. I read like it is and lean towards the facts that have been proven thus far. :dontknow:
 
#227 ·
There's basically 3 qualifiers.

The amp cannot be designed to color sound.
The amp needs to be correctly built (which is most commercial amps)
The amp cannot be asked to do more than it is actually capable of doing (run 1ohm loads (excepting amps that can do this like many McIntosh or Krell amps) or driven to clipping)

I think it should be really obvious that an AVR amp asked to run a 1ohm load @300w will catch fire and fail. Yea: it will sound different.
 
#230 ·
Very well said terry.

And Jerry... I wonder what percentage of solid state amps manufactured would fall into those three qualifiers? Obviously it would be a total guess, but I have to believe that most amps built today would be included, with only a few exceptions of the poorly designed amps that probably not a lot of folks are buying.
 
#236 ·
And Jerry... I wonder what percentage of solid state amps manufactured would fall into those three qualifiers? Obviously it would be a total guess, but I have to believe that most amps built today would be included, with only a few exceptions of the poorly designed amps that probably not a lot of folks are buying.
The third qualifier cannot be said of an amp: It can only be said of an amp-speaker pair.

I think most commercial separates would meet #1 and #2. I think that the exceptions would be the exotics.
 
#231 ·
I say I can hear a difference, although I agree I have not been in a double blind. However, this statement is not so cool..

"I just kinda get stuck on the 'arrogance' of people maintaining they have no biases without ever finding out. Sure, it's all well and good to simply maintain something (you know, the earth is flat) yet have absolutely nothing on which to base that stance. Hop on a psychology forum and tell them you have no biases and your conclusions are not influenced in any way from your past experiences in life. (that was the general you by the way) It would be interesting to see what the reaction would be!

So it seems if I disagree with what a percentage of others say, and because its different I am biased...well ok I may be biased by my experiences but I certainly am not arrogant. Please do not go to the location where believing in something without proof on which to base a stance. Much of life is believing in something which we do not have concrete proof.
Now obviously my conclusions are based on experience, as are everyone's here I am no different, my opinion is different and since my opinion is similar to just under half the folks that have taken this poll, I guess that opinion is pretty popular. All these opinions work 2 ways, ours and theirs. Because someone has not proven something means little in way of science today. Many things are yet unproven. Higgs Bosen sound familiar or maybe something a little more everyday...memory, can we show how memory works, not just where it might be stored. And if we cannot prove how folks recall short, long term does that mean it does not exist ? The brain and body do work on electrical impulses, we should be able to hook us up to some gizmo and voila, an answer. Even the great Thomas Edison admitted he did not know everything by saying he did not fail,he just found 10,000 ways that dont work. It would be sheer hubris to admit we can tell everything that is going on in the reproduction of sound because we dont. Things change daily....just wait and someone will get it.
 
#260 ·
I say I can hear a difference, although I agree I have not been in a double blind. However, this statement is not so cool..

"I just kinda get stuck on the 'arrogance' of people maintaining they have no biases without ever finding out. Sure, it's all well and good to simply maintain something (you know, the earth is flat) yet have absolutely nothing on which to base that stance. Hop on a psychology forum and tell them you have no biases and your conclusions are not influenced in any way from your past experiences in life. (that was the general you by the way) It would be interesting to see what the reaction would be!

So it seems if I disagree with what a percentage of others say, and because its different I am biased...well ok I may be biased by my experiences but I certainly am not arrogant. Please do not go to the location where believing in something without proof on which to base a stance. Much of life is believing in something which we do not have concrete proof.
You missed the point.

We are ALL biased and influenced by the sum and cumulation of everything before us in our life. It has absolutely nothing to do with you having different thoughts than others as being proof of being biased.

Being human is sufficient proof you have bias, nothing more. Give us, in whatever amount of detail you are able or feel the need to, all the points of fact and data you have that shows us not only that you investigated whether you have biases or not (include details of the experimental procedure) but also that indeed, at least in the case of amplifier differences that you are completely unbiased.

If, as I suspect you have not done anything of the sort then it is nothing more than a claim on your part of being 'special'. You are indeed different from every other being on the planet.

Your moral indignation and sputtering actually did little to disprove every part of my post you quoted, rather it instead proved my post completely. And I am even more stuck on your arrogance I am afraid.




You know that is a good point but I personally do not believe in DBT. It just is not how our brains work. There is a reason that most people are said to do no better than chance.
I am not even sure what this sentence says. Strangely tho, there is something accurate in there and even more strangely one that runs counter to the point you are trying to make. You are correct it is not how our brains work precisely because it intends to remove the biases which (yourself excluded it seems) we all fall prey to.

You claim also to be intellectually curious and honest, so is it at all possible another plausible reason most people seem to return chance results is that most amps not driven past their limits do indeed sound alike?? Why was that possibility not part of your list of plausible explanations? Why instead did you run to it (sounding alike) being some proof that dbt's don't work?

Can you show us your investigations into why dbt's don't work. Or is that just another 'just cause I say so' type of thing.

I have heard differences in amps, some interconnects and cables, pre amps, DACs etc and I know this as a fact. There can be no way to convince me otherwise.
We all agree with you, and all agree it is a fact. We have no doubt that for a fact you have heard differences between amps, pre's and cables et al.

There is no need to convince you otherwise nor do we want to. To do so would be to call you a liar, we believe you when you tell us you have heard differences. We do not think you are lying.

Look up something done by Jon Dunlavy, you have probably heard of him. Equally, if you know of him you also respect him and his contributions to audio. His views on cables (NOT AMPS AS BEING DISCUSSED HERE) (, sorry bout caps lock) but as you will see, none the less pertinant.

ALL he had to do was to get his assistants to hold up and show to the listening audience some python sized cables behind his speakers.

Not say a word, do nothing else. Then they would bend down out of sight.

It was never said of course, apart from the holding up, but the audience assumed that those cables were now in use when NOTHING was changed at all. The original cables were still connected to the speakers.

Naturally all listening were flabbergasted at the improved resolution, the sudden appearance of previously unheard details in the music.

Bias, suggestion and other cues are part and parcel of the human existence. We cannot but help to be influenced by our conclusions.

You gonna tell me someones conclusion that they are not subject to error and have no bias will NOT have an effect on their perceptions or stance on matters?? And that that somehow magically disproves the statement they will be affected??


That would truly be awesome.
As an owner of a respected forum you, with time taken and care to do it would be in a position to garner good results.

It will never change things much tho. We as humans can rarely examine our stance dispassionately. That works both ways...you'll never convince the amp guys by a result, and let's say you found a difference you'd never convince the naysayers.

I find it rare that people are honestly after the truth.
 
#233 ·
With all the qualifiers, no doubt you guys are correct.

Anyway,
It is the Emotiva amp that hums. They told me it might be audible b/c my speakers are fairly efficient. I was actually shocked that it is. With music on though... It's certainly not much of an issue. Can't say it's detrimental to my enjoyment. I just wanted more power b/c I had clipped my old amp a few times. Haven't had that happen on the Emotiva. The hum that one of my sub amps make gets my goat a bit though.

The T-amp made sonic compromises to be portable/efficient. Not a bad amp even if not HiFi. Funny that so many were crowning it, but it's certainly not sonic magic. I didn't think it would be though. Just wanted a boom box.

Dan
 
#239 ·
It is the Emotiva amp that hums. They told me it might be audible b/c my speakers are fairly efficient. I was actually shocked that it is. With music on though... It's certainly not much of an issue. Can't say it's detrimental to my enjoyment. I just wanted more power b/c I had clipped my old amp a few times. Haven't had that happen on the Emotiva. The hum that one of my sub amps make gets my goat a bit though.
I may have to reconsider whether amps sound different or not. If an amp produces audible hiss when there should be silence I would say that would meet all of the qualifiers and would indeed sound different and be easily identified by the most casual observer.
Or would that put Emotivia in the poorly designed category ?
Would there be any benefit in Emotiva creating an amp that performs better with lower sensitivity? If not then it would have to be considered a poor design, would it not?

If I go to a DBT and hear hum in one amp and none in the other, no doubt I am going to hear a difference. If one of the amps were mine then I would be able to identify the amps when comparing them. I would not want to buy an amp with audible hum and would look for one that works best with my speakers, which is apparently what I did.

I am having to replace one of my Behringer EP2500 amps because it developed a hum... one of those that prevented the sub driver from performing as it should. However, I have the Emotiva XPA-1 monoblocks powering my MartinLogan Prodigy's and have no hum, but the ML's are a little more difficult to drive too.

I purchased my XPA-1's because I like how they look, I wanted a lot of power, Emotiva is a sponsor and I got a good deal on them. Let's suppose that I was in the market and did not care what the amps looked like... Emotiva was not a sponsor and the market was wide open for me. I could afford any amp I want, but I prefer to get the best bang for the buck, because like I said, I don't care what they look like. I just want them to work, sound like they are supposed to sound and power my speakers like they should. What makes a $25-30,000 pair of Krell 600e's (1200wpc) sound that much better than using a pair of $1,700 XPA-1's (1000wpc) or a pair of EP2500's in a bi-amp (600w + 600w per speaker) setup for less than $600? Should I be able to hear a difference between the three?


I am a bit curious to find out if any of those that responded in the affirmative have ever participated in a blind comparison. Another poll could shed some interesting light on the results here.
I have only ever heard/read about DBTs where participates could not tell a difference between two amps, but I would like to participate in one anyway just to see if I can hear a difference.
 
#237 ·
I may have to reconsider whether amps sound different or not. If an amp produces audible hiss when there should be silence I would say that would meet all of the qualifiers and would indeed sound different and be easily identified by the most casual observer.
Or would that put Emotivia in the poorly designed category ?
 
#251 ·
That's the signal-to-noise ratio or "noise floor". Assuming it's actually being introduced by the amp; it's likely a problem with the amp. There's actually considerable discussion on Emotiva threads regarding this where some report hiss and others do not. In cases where it has been reported: I believe the power transformer was identified as the issue and Emotiva replaced it under warranty.

It's also possible to be introduced pre-amp. The signal coming into the amp is not truly silent. If you add enough gain, you'll hear hiss on anything. It could be an interconnect or some component earlier in the chain.

All that said. Unless the hiss is so loud you are hearing it at your listening position and at normal volume settings; you are unlikely in the extreme to notice any difference during actual playback.

But yes: if the Emotiva is hissing and another amp at the same spot is not hissing, then there's a problem with the Emo.

For example: http://emotivalounge.proboards.com/index.cgi?action=display&board=speakers&thread=9886&page=1#156420
 
#238 ·
I don't know that I'd even say it's poorly designed. It does kind of stink that my old HK3490 doesn't produce an audible hum with the same speakers. I don't recall my Onkyo doing it either. None the less, the Emotiva has a little more headroom--or it least it should. Anyway, I could have returned this and got a different one, but I didn't.
They told me I may need to get the cheaper amp or I may hear a hum with my speakers. They said it was d/t the higher gain on this one. :/

Dan
 
#240 ·
What makes a $25-30,000 pair of Krell 600e's (1200wpc) sound that much better than using a pair of $1,700 XPA-1's


I dont think it fair to say better necessarily, but Different, most probably. This will of course depend on the listener and interaction between the speaker and the amp.
 
#241 ·
That is why we need DBT, to help determine if there is a difference and be able to identify it... describe what that difference is. Why is it different, especially if it is not for the better. Why does that difference cost so much, especially if it is not for the better. Why are there no DBT with anyone recording and confirming these differences?

I know that I have a very long list of amps I have tried and I cannot remember ever being able to hear a difference... including receivers. What made the most difference to me was speakers. It would be great to be able to hear a difference if it were better. I would love to have an experience equal to that of finally finding the right speakers.
 
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