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$10k golden ears AMP challenge!


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#21 of 1046 OFFLINE   Mark gas

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Posted November 01 2002 - 03:24 PM

Richard Clark did a test on tube amps too. He said tube amps just add distortion and he could bet a/b class amps to sound the same when he added distortion to them.

#22 of 1046 OFFLINE   John Kotches

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Posted November 02 2002 - 04:11 AM

Seth,

What is written within this forum I've responded to. The series of posts specifies car amplifiers.

Non-dynamic speakers are excluded from the test -- which means planar magnetics, ribbons and electrostatics are not allowable.

This further skews the test in the favor of the person issuing the challenge, as the above speakers can be one of the most difficult to drive.

Of course once you start dictating the choice of speaker driver type, then start messing with the input and output loading -- in other words Real world conditions then yes, differences get diminished.

As far as having anything to lose, you seem to think my livelihood derives from my A/V writing. It doesn't.

With respect to my credibility, my body of writing speaks for itself.

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#23 of 1046 OFFLINE   Ludwig Crumb

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Posted November 02 2002 - 05:24 AM

Clark claims that you can duplicate the sound of a tube amp by adding s 0.2 ohm resistor (i think that was the value) on the speaker leads of the transistor amped speaker.

if the gains and volumes are properly matched (so the theory goes) there will be almost no difference between the tube and transistor amp.

#24 of 1046 OFFLINE   Michael Roderiques

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Posted November 02 2002 - 06:14 AM

Well I guess this just goes to show that some one can come up with some form of "evaluation" or "testing" method that like any other has little or no value.

Funny thing about statistics, they can prove just about anything you want. just depends on the data collection method.

Paper will lay still and let you write anything on it.
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#25 of 1046 OFFLINE   Ludwig Crumb

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Posted November 02 2002 - 06:33 AM

I respect his knowledge and when looking at the big picture, I believe he is right. My only problem with him is that his testing criteria is too lopsided. I suppose if it was my 10 grand at stake, I would try to swing all the variables in my favor as well.

#26 of 1046 OFFLINE   Chu Gai

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Posted November 02 2002 - 06:38 AM

I'd be pleased to simply have the levels matched at the speaker terminals with neither amp being driven past its ability to perform.

#27 of 1046 OFFLINE   Lin Park

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Posted November 02 2002 - 08:31 AM

If you normalize enough things, then you won't be comparing A to B - you'll be comparing A to A and have no chance of winning this. From a theoretical standpoint he may be right, but does everyone who purchases electronics have the ability to make the mods to the front and back end that are being proposed?

I'd propose you bring some solid state amps over to my house and we'll compare them to my tube amps. If I can't tell the difference 100% of the time, you can sit and watch me cry for the rest of the day. Posted Image

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#28 of 1046 OFFLINE   Chu Gai

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Posted November 02 2002 - 09:43 AM

Just ensuring the signals going to the speakers are the sam should be sufficient. You might find the following bit old history interesting.
Quote:
At the 85th AES Convention (Los Angeles, Nov. 3-6, 1988), a workshop entitled "Esoteric Audio: Can You Hear It?" was held: three days of controlled listening followed by a panel/audience session on the fourth day (disclosure of results, discussion of issues and PUOSU ultimatum).
At issue, representative controversial effects: the audibility of distortion, tube sound vs. transistor sound, and audible differences between speaker cables. Three separate listening rooms were set up and run by assigned room captains:
1) loudspeaker cable room by Ian Eales, a recording studio owner (whose studio is wired with cable of the same brand as tested) and proponent of specialty cables;
2) tube-vs.-transistor amp room by Michael Fremer, a contributer to some underground audio mags and proponent of "tube sound";
3) distortion room by Peter Sutheim, professor and audio talk-show host.

For speaker cables, the comparison was between 12-gauge zipcord and cables from a well regarded exotic brand. The amplifier comparison was between a ("bad sounding", ugly looking) Crown transistor amp, a Threshold transistor amp and a VTL tube amp. Switching between the DUTs (for both amp and cable tests) was done by manual cable swap (probably not to have the "obvious" differences burried in the "audible" added distortion, and other "veiling effects", of a good switcher...)

The listeners were convention attendees (at the invitation of workshop Chairman David Clark), by all means experienced and critical listeners since AES conventions are usually attended by professional audio people, recording engineers, designers, ultra-serious audiophiles,... With such a large, educated listening panel, no doubt if there were "obvious" differences, they would be heard, and even the less obvious that would elude most RAO readers... (no insult intended here, just acknowledging reality)

Before announcing the results at the panel session on the fourth day, Chairman Clark asked those in the audience to express by a show of hands whether they believed that well designed power amps (measuring well in standard tests) sounded/would likely sound different from each other in level-matched listening comparisons (units operated within specs).
About 3/4 of the audience believed so, and this despite several carefully conducted/controlled listening tests (very likely well known to them prior to November 1988) that have indicated that sonic differences between amps are at best very small, if any.

For _both_ wire and amplifier comparisons, results indicated that these professional audio people (forming a large scale listening panel) were doing no better with their ears than they would have done with a coin to tell audible differences, with an average score very close to 50%, indicating that audible differences were extremely small, if there were any at all. I'm pretty sure the room captains tried to influence listeners with their biases but their efforts were randomized anyway
(matched levels and blind calling).[Listening, Mr. Dickson?]

The discussion panel was divided into two groups: the "men of faith" (the room captains and Noel Lee [Monster Cable]) and the "men of science" (Gene Pitts [then at Audio Magazine], Prof. John Vanderkooy [then at the U. of Waterloo, Ont., Canada], Prof. Dick Greiner [at U. of Wisconsin] and Floyd Toole [then at NRC of Canada]). The discussion extended to
the audience and became very lively at one point (to put it mildly ).

It is clear from the audio tape that Noel Lee didn't (want to?) know what he was doing and had no technical facts to offer to support his claims (not even a lame attempt a la MIT), but faith in what he believes a.k.a. personal opinions. He avoided as much as he could the issue of blind listening at Monster Cable. The scientific side of the panel argued solidly that, if there are real audible differences, they must be audible in controlled listening and if these differences are audible, they must be measurable in some way (cause ---> effect).
--
,
Sebastien


Sources: - 85th AES Convention Report, JAES, Vol.36, No.12, Dec. 1988.

Audio tape of "Esoteric Audio: Can You Hear It?", Workshop 18, 85th AES Convention (available from: Mobiltape, 25061 W. Ave. Stanford, Suite 70, Valencia, CA91355).


#29 of 1046 OFFLINE   Manuel Delaflor

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Posted November 02 2002 - 12:44 PM

I think the test is absurd, if we can't test the amplifiers at their limits, what's the point of the test?

I know, to see if there is a "sonic signature", or sonic differences due to the topology of the design, or something like that.

But for me this is like comparing a Ferrari with a Yugo, only that we most use the same seat on both cars, be unable to see or hear the engine or smell any difference and then asked to tell if we can perceive a difference in both cars running at 20MPH on a good paved road with no curves.
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#30 of 1046 OFFLINE   Gabriel_Lam

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Posted November 02 2002 - 01:47 PM

Or like comparing two different kinds of fruit purely by taste, only we cannot see the fruit, cannot smell the fruit, and the fruit is cut into exactly the same size, shape, and the more moist one is dried so that the moisture & texture levels are the same. Sounds pretty easy if there's a "huge" difference.
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#31 of 1046 OFFLINE   Seth_L

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Posted November 02 2002 - 02:03 PM

Quote:
I think the test is absurd, if we can't test the amplifiers at their limits, what's the point of the test?
Manuel I would stagger that most of the people here aren't testing the limits of their amplifiers on a daily basis. Even when you're listening to a movie at reference volume if you've properly sized your amps They're not breaking a sweat. So if typical conditions don't test the limits of the amplifier why test them under such grueling conditions?

Test a QSC PLX3402 against a boutique amp. If your speakers can sucessfully test the limits of the QSC then the boutique amp will have given up already, or you'll be deaf. QSC PLX series amps are stable under just about any driving conditions you can create. This includes reactive loads. If 1100Wx2 into 4 ohms at .05% THD isn't sufficient I'm not sure who makes an amp that can drive the load in question. Odds are the electrical circuit that you have the amp plugged into will give out before the amp. The amp can draw 39A from a 120VAC line when delivering all it's power into twin 4 ohm loads.

Seth

#32 of 1046 OFFLINE   glen donald

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Posted November 02 2002 - 06:23 PM

Hi all,

Good to see we are having a healthy debate – as it should be, afterall why should be believe certain amps are best because it was claimed by the manufacturer or audiophile to be so, right?
Anyone who says “ampX” is better than “ampY” because it has “better imaging” should be able to PROVE it. Otherwise you should make such statements.

I’d like to clarify a couple of things:
The “rules” were originally written for Car audio amps, it is old and needs a little updating because it has been brought to home audio as well.
Firstly, you don’t have to be in the industry to take the challenge, ANYONE can take it if they are confident of their ability. ALL commercial amps are allowed – NO LIMITATIONS, if you have a $100k super amp, test it against a “cheap” amp. I think clipping should be allowed because it wouldn’t prove that amp A is better than amp B by virtual of better design and “super imaging” attributes that are claimed, rather than AMP just has more power than amp B. e.g a lot of expensive tube amps are only 10-15watts, so comparing power only isn’t fair on the tube amps. We are after differences in SOUND QUALITY – that’s where all the fuss is!

On to preliminary: The preliminary process is to judge if you are wasting your time due to things like “partial deafness” – e.g if you can hear the difference within +- 1db in volume. If you pass this (6 out of 6) then you take the important A/B sound quality test.
Remember in the A/B test, it can be done on your own speaker, cables, amps, lounge chair, you can supply everything – he has done this to extinguish *excuses* people make after they fail the test using his equipments.

If you feel like 12 out of 12 is too tough, then you can reduce it down to 6 out of 6 – but people who boasts greatness about their amps and are confident enough to turn it from a “challenge” into a “bet” – your money against his. Hey if you swear your amp is THAT MUCH BETTER, then how hard could 6 out of 6 be right?

This is what he has to say recently:


i'll take a challenger that thinks he has the worlds best home amp up against a run of the mill car audio amp any day of the week------whats so special about "high end" home amps-------nothing except that the marketing BS is deeper--------tell them to pack em up and "come on down"----------i guess you havent read about the challenge i did with the company that makes high end tube amps------"single ended triodes"-------i made that challenge $45K------with the requirement only 6 out of 6 against a commercial grade Crown DC-300--------and they lost!!!!!----- it wasn't my normal challenge------the sales manager visited our CD plant and commented that we could improve our studios if we upgraded our amps-------i told him i didn't believe it would make any difference------i stated that if he could show me that he could show me that he could hear the difference in his amps ( i believe they were 15K a stero pair) that i would buy them for all three of our mastering studios-------that would have been 45K-------i actually took a signed purchase order with me and laid it on the coffee table before the test------we did the test in his own listening room on his own equipment using LP records!!!!!!(you know cause vinyl is superior to CD's)------after only 4 or 5 tries he gave up and admitted he could not tell a difference--------if i remember correctly Manvill's wife Ellen was there and witnessed the entire thing.......... we did the test in his house on his personal system-------if you know them ask around------it is not possible for him to forget this even though i can see why he might want to...........RC


“Manvill” (Smith) referred to is Head Technical at JL audio, one of the leaders in CarAudio equipments.

Yep so he’ll also do a “top-of-the-line” home amp against a “run-of-the-mill” car amp, or any combinations of it.
Hope that clears one or two things!

#33 of 1046 OFFLINE   glen donald

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Posted November 02 2002 - 06:46 PM

To answer the question about where it can be done:

Well normally – you go to his company, he has some of the most expensive equipments that you and I could only dream of owning – speakers, amps ect….ALSO he has some of the “budget” stuff. If you want to use his equipments - OR to save on all the *excuses*, you are welcomed to bring your own.

As you read my previous post, if the challenge is BIG enough, he’ll go to your place. But because he is very busy, no time wasters – ONLY serious people! (Read my previous post). But hey if you are confident, spend a grab yourself a plane ticket, take the challenge and win $10k – after expenses, you’ll still end up with $9k profit atleast. It shouldn’t take more than a couple of hours, but if you fear “listening fatigue”, take all the time you need to complete the challenge or come back another day when you are fresh! How often do you get to profit $8-9k from listening to music for an hour or two.


The way claims are made, as if it’s like “night” and “day” – Should it take longer than 1-2 hours to pick 6 out of 6 or 12/12?

And again, ALL COMMERCIAL AMPS ARE PERMITTED. Krell and Mcintosh – he has the lot at his company – bring your own or use his.

There’s a good reason why non-dynamic speakers are not allowed – Think about it in terms of manufacturer’s claims and think about ALL amp designs. It is clearly better to use dynamic speakers.

[edit]
One more than, the reason why the "challenge" must be at least 12/12 is because he wanted to eliminated the possibility of a complete fluke...it's bound to happen that someone could win it by accident. Again those who can HEAR differences shouldn't need the possibility of fluking through.
[edit]

#34 of 1046 OFFLINE   Saurav

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Posted November 03 2002 - 03:27 AM

Quote:
To answer the question about where it can be done

Thank you for providing this information.

#35 of 1046 OFFLINE   Guy Usher

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Posted November 03 2002 - 04:25 AM

You won't catch me going 200 mph in a YUGO. . . Why do all these tweakers hate double blind test... You know why. . .
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#36 of 1046 OFFLINE   Lin Park

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Posted November 03 2002 - 10:52 AM

Let me get this straight: he says there is virtually NO difference between amps but that there is a chance that someone could get lucky 6 straight times but NOT 12 straight times? Riiiiiiiiiigggght.

Lin

#37 of 1046 OFFLINE   RobertR

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Posted November 03 2002 - 11:44 AM

Quote:
he says there is virtually NO difference between amps but that there is a chance that someone could get lucky 6 straight times but NOT 12 straight times? Riiiiiiiiiigggght.


Despite your sarcasm, he's right in saying that the odds of getting it right 12 straight times due to sheer luck are very low, and that the odds of being lucky 6 times in a row are much higher. Randomly getting an A/B choice correct is the equivalent of a coin toss. You are aware that the odds of having a coin toss come up heads 6 times in a row (1 out of 64) are MUCH higher than having it happen 12 times in a row (1 out of 4096), yes?


#38 of 1046 OFFLINE   Craig_Kg

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Posted November 03 2002 - 11:48 AM

Why doesn't someone in Burlington just give it a go? They'd have nothing to lose (except face).

I'd be rollingup with a different amp every week Posted Image
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#39 of 1046 OFFLINE   Ludwig Crumb

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Posted November 03 2002 - 01:50 PM

Anybody remember Peter Aczel?

#40 of 1046 OFFLINE   Andre D

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Posted November 03 2002 - 02:06 PM

Quote:
Despite your sarcasm, he's right in saying that the odds of getting it right 12 straight times due to sheer luck are very low, and that the odds of being lucky 6 times in a row are much higher. Randomly getting an A/B choice correct is the equivalent of a coin toss. You are aware that the odds of having a coin toss come up heads 6 times in a row (1 out of 64) are MUCH higher than having it happen 12 times in a row (1 out of 4096), yes?


You took the words right out of my mouth. It's just it funny that everyone is so quick to dismiss the challenge when it makes a lot of sense.


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