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Benchmark AHB2 / Class D Purifi Eigentakt / Mark Levinson 333 - Listening impression & Conclusion

Gorgonzola

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did you read #74? Best case there are very little differences between amplifiers. The likely explanation is that differences are not audible. Then X or Y came and tell they hear obvious differences between amps but they don’t have a methodology to reduce bias. Then X or Y have a hard time to convince rational people.

I have never been able to hear a difference between my accuphase and my crown. And I can tell you, I really wanted the accuphase to sound better.
Gosh ... my first reaction is 'Listen more carefully'. Then I realize that as an objectivist you are probably biased against hearing differences. We are all victims of our biases.
 

SIY

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I do not take it personally. Some folks here just refuse to even consider anything if they have never read a paper about it. The alleged facts (?) about distortion and scene size I have heard from amp designers and apparently it is a quite common lore in the field. Yes, there should be papers documenting proper experiments to confirm or confute these assertions. Sadly, in this field this is rarely done. I was a bit puzzled when I saw people here drooling at the idea Bruno Putzeys would answer their questions and the same people even refusing to consider that hysteresis distortion may be a fact because they are not aware of ABX experiments (of course, in a different thread, assuming that Putzeys won't read ;-) )
Evidence is what matters. Not papers or whatever. Forty years of assertions about the “sound” of electronics, and yet zero, nada, bupkis from anyone making the claims.

To quote Christopher Hitchens, what can be asserted without evidence can also be dismissed without evidence.
 

Inner Space

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Gosh ... my first reaction is 'Listen more carefully'. Then I realize that as an objectivist you are probably biased against hearing differences. We are all victims of our biases.

Genuine question - are you serious? Seems to me most anyone would be seriously biased in favor of earning 10 large for an hour's work. Yet the post referred to shows that thousands of people have tried and failed. If only they'd realized they should listen more carefully! Why on earth didn't they think of that?
 

audio2design

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Gosh ... my first reaction is 'Listen more carefully'. Then I realize that as an objectivist you are probably biased against hearing differences. We are all victims of our biases.

And my answer would be stop listening with your eyes.

I've lost count of the number of claims that audiophile friends have made that disappear in a blind level matched test. Heck I will sometime play with the level to get the exact opposite result of what they were expecting just to show them how critical comparisons must be and how flaky their perception is.
 

mocenigo

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Evidence is what matters. Not papers or whatever. Forty years of assertions about the “sound” of electronics, and yet zero, nada, bupkis from anyone making the claims.

To quote Christopher Hitchens, what can be asserted without evidence can also be dismissed without evidence.

You are however making a mistake here. I never asserted that it is like I said and that it is the absolute truth. I am sharing point of views and experiences which are clearly described as sighted and not controlled.

Also, the quote is not the most brilliant thing by Christopher Hitchens – if one asserts X without evidence, his assertion act can be dismissed without evidence. Not X itself, which may have supporting evidence independently. Of course if X is not only asserted, but it is also claimed that evidence is not necessary and, as in religion, even detrimental, well, then it is clearly bollocks :)

The challenge in post #74 is clearly for amplifiers within parameters that do not stress them - for the anecdotal phenomena I was mentioning you need to bring the amps to stressing them.

Since I switched to high efficiency speakers I doubt I will ever stress my amps in any way, so I do not think I would be able to perceive any difference.
 

mocenigo

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did you read #74? Best case there are very little differences between amplifiers.

Not only I read that, but I was very well aware of that challenge. The interesting point is that the allowed working parameters of the amp are presumably quite strict. And the I do believe that differences are non existent or non audible anyway. This is also why I designed my amp to be a bit overkill (Purifi modules, Neurochrome Universal Buffer) for my highly sensitive speakers. To be sure to be well within that optimal working area.
 

SIY

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You are however making a mistake here. I never asserted that it is like I said and that it is the absolute truth. I am sharing point of views and experiences which are clearly described as sighted and not controlled.

Also, the quote is not the most brilliant thing by Christopher Hitchens – if one asserts X without evidence, his assertion act can be dismissed without evidence. Not X itself, which may have supporting evidence independently. Of course if X is not only asserted, but it is also claimed that evidence is not necessary and, as in religion, even detrimental, well, then it is clearly bollocks :)

The challenge in post #74 is clearly for amplifiers within parameters that do not stress them - for the anecdotal phenomena I was mentioning you need to bring the amps to stressing them.

Since I switched to high efficiency speakers I doubt I will ever stress my amps in any way, so I do not think I would be able to perceive any difference.
So much handwaving to avoid basic controls.
 

Wes

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Nothing wrong with sharing points of view (engineering judgement is one) and experiences which are clearly described as sighted. But these things are mostly useful to guide where effort should be expended in doing a controlled listening test, or measurements.
 

Phorize

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Ok. pace and rhythm or PRAT factor is perceived speed or attack. There are big differences in that among amps. How it is possible? I will explain.
When amp has very high dumping factor it grips the speaker driver firmly, thus bass stops fast and do not go deeper due to inertia (opposite is loose bass, that may go deeper but the accelleration from "the deeper point" takes longer time). Class D is perceided as "fast" (but in fact the rhythm is the same of course, that is only the perception of the character of the bass).
Mixing quasi-engineering language with audio marketing terms as above may be common approach on other forums but it’s not considered helpful here. Specific falsifiable claims were made further above, unsupported with actual evidence unfortunately.
 

Phorize

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I do not take it personally. Some folks here just refuse to even consider anything if they have never read a paper about it. The alleged facts (?) about distortion and scene size I have heard from amp designers and apparently it is a quite common lore in the field. Yes, there should be papers documenting proper experiments to confirm or confute these assertions. Sadly, in this field this is rarely done. I was a bit puzzled when I saw people here drooling at the idea Bruno Putzeys would answer their questions and the same people even refusing to consider that hysteresis distortion may be a fact because they are not aware of ABX experiments (of course, in a different thread, assuming that Putzeys won't read ;-) )
Something of a straw man of the challenge you’ve received don’t you think? No one is complaining about general conjecture-the forum is full of it. How ever when you advance statements such as ‘A signature aspect of high-tier Class D amplifiers is that the image is stunningly stable, not particularly wide, but with a deep stage, and sounding a bit rolled off in the treble with respect to high bandwidth AB amps’, which is clearly intended as a statement of fact, expect to be asked for substantiation.
 

pierre

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Gosh ... my first reaction is 'Listen more carefully'. Then I realize that as an objectivist you are probably biased against hearing differences. We are all victims of our biases.

As a mastering eng. I find your answer amusing. You are trolling right?
 

restorer-john

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The requirements were stringent. They included level-matching, limiting loudness according to the lower-powered amp, running each amp in its linear range (no more than 2%THD), and eq'ing out any baked in frequency-response non-linearity (often just by adding a cheap capacitor to one amp's speaker leads).

Adding a capacitor anywhere (either series or parallel) over speaker leads is only going to handicap one amplifier with respect to the other. It'll either act as an HPF (series- high value) or a LPF (parallel- low value).

EQ'ing out frequency response anomalies makes the entire "test" useless. So, he made the amplifiers sound the same, excludes the amplifiers with residual noise (all of them), handicaps the powerful ones and wonders why nobody can claim the prize in his stacked 2x12 correct ABX challenge? :facepalm:
 
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boXem

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Adding a capacitor anywhere (either series or parallel) over speaker leads is only going to handicap one amplifier with respect to the other. It'll either act as an HPF (series- high value) or a LPF (parallel- low value).

EQ'ing out frequency response anomalies makes the entire "test" useless. So, he made the amplifiers sound the same, excludes the amplifiers with residual noise (all of them), handicaps the powerful ones and wonders why nobody can claim the prize in his stacked 2x12 correct ABX challenge? :facepalm:
I would have added a bit of DSP, just to be sure...
 

DHT 845

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Mixing quasi-engineering language with audio marketing terms as above may be common approach on other forums but it’s not considered helpful here. Specific falsifiable claims were made further above, unsupported with actual evidence unfortunately.
That is pure rhetoric, zero correlation to the truth
 

Purité Audio

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I have compared Benchmark, and March Audio’s iterations of both the Hypex and Purifi class D, couldn’t hear any difference whatsoever.
Haven’t tried the Levinson.
Keith
 

Katji

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Evidence is what matters. Not papers or whatever. Forty years of assertions about the “sound” of electronics, and yet zero, nada, bupkis from anyone making the claims.

To quote Christopher Hitchens, what can be asserted without evidence can also be dismissed without evidence.
Yes but human psychology is even more "inaccurate" than human sensory perception. ...The general thing is that the widespread repetition of the assertion becomes the evidence, so to speak, and so it is not dismissed.
 

restorer-john

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Pink noise. Surely, we can all agree it is a reasonable and representative environmental/stimulus sound, not terribly artificial (been to a surf beach lately?) or diabolically dangerous to HiFi gear.

Use it for comparing anything you like, particularly amplifiers in A-B comparisons.
 

Gorgonzola

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Gosh ... my first reaction is Listen more carefully. Then I realize that as an objectivist you are probably biased against hearing differences.
As a mastering eng. I find your answer amusing. You are trolling right?
No, I wasn't trolling. Subjectivist audiophiles' SQ opinions are dismissed on the basis the they are confirmation bias. How is that objectivists, (apparently including mastering engineers), may be assumed to be without bias? Perhaps they hear no differences because hearing none confirms their biases.
 
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