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Old 05-05-2012, 06:31 PM
mutescream mutescream is offline
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Default Richard Clark Amplifier Challenge Discussion (split from the FLACs And MP3s thread)

This edit was inserted into mutescreams post to by skip252 to explain why posts were moved here

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The Software forum sticky "FLACs and MP3s" initial post contains a reference to the Richard Clark $10,000 Amplifier Challenge FAQ. A forum member felt that the reference and testing weren't appropriate. That triggered a debate/discussion that was outside the original intent of creating a sticky that members could use as a reference when discussing ABX testing of audio files.

There were appeals to either delete or relocate the posts that were outside the original purpose of the sticky. saratoga's response was
Quote:
Originally Posted by saratoga
I'll probably just delete this crap once its over. Until then, its probably easier for everyone if we keep it in the same thread.
Members appealed to not have that happen as they felt the discussion was interesting and informative. Moving these posts here is an effort to fulfill that request and stop the disruption of the original thread.

Please use this thread for any further discussions about hardware testing once it's unlocked. Hair splitting as to what constitutes hardware vs. software testing won't be tolerated.

Moving the posts and then unlocking this thread may take a bit as I'm trying to be careful to not break the continuity the discussion in the other post had. I'm also trying to make sure any information that might be helpful won't be lost.

Also any continuation of the rudeness that cause the other thread to be locked and triggered the clean up won't be allowed. If you can't figure out how to play nice you won't be able to play at all.
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Quote:
Originally Posted by Enigmatic View Post
land.com/tests/ampchall/index.htm"]Expensive amplifiers sound better than ordinary amplifiers debunked.[/URL]
From that link:

Quote:
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
and

Quote:
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.
but this is where it kind of gets to the point:

Quote:
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.
What this test ignores is that a more expensive amplifier's quality difference is by and large going to be based on several factors... Such as linearity, or a preferred sound characteristic. Such as a warmer sound, as comes from tubes... Due to solid state amplifiers inherently relying on negative feedback for stability (which cancels out even order harmonics).

His tests rely on coloring the results to make "all things equal", when in fact they are not. He stacked the deck in his favor, before the test even began. I could respect it, if he wanted to place limitations on the volume control to ensure no one clipped an amp to reveal its identity. But, he went waaaay beyond that.

As for the wire one... I agree that wire would not make a difference the vast majority of the time. The only time I could see it making a difference at all, is in situations of a very high powered amp pushing inefficent speakers (such as planars). The only reason I believe it to be possible under that circumstance, is that issues such as capacitance and signal degradation due to resistance (not to mention the characteristics of the speaker wire changing due to temperature) of using too small of a cable for the signal going through it. According to Magnepan, some of their speakers can take 1KW. On a 5ohm load (what their speakers are rated at), that's a 14A 72V RMS signal (which would be ~103 VAC peak, ~206Vp-p) going through the wire. Using 16 or 18 gauge wire is just not going to cut it (not just for SQ, but also for fire safety reasons). Then you also take into consideration the length of the wire itself and the inherent resistance of the wire itself increasing with length...



I concede that the vast majority of the time, and for most applications the wire itself won't make much of a difference. But making the broad sweeping statement that it never makes a difference is just as false.

Amplifiers have their own signatures, based on their linearity and on their odd and even order harmonics. Unless you cripple one amplifier, either through equalization or limitation of power, you will NOT be able to make all amplifiers equal in the real world, when driving certain speakers and headphones.

Were that the case, then those two tests would make a case for external headphone amps being purely placebo effect and non essential for driving certain headphones. They could even be extrapolated to conclude that all headphones sound the same.

Truthfully. neither of those ABX examples are even remotely relevant to comparing codecs for audio compression (or lack thereof). Better examples would be comparing analog and digital recordings (mastered the same) or DACs to one another.

Last edited by skip252; 05-11-2012 at 08:51 AM.
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