You are being a bit hard on Mr. Nelson Pass, but one could ask how many different model amps he has created since his Threshold days, I have owned a couple (pretty good amps actually). And now the J whatever, the pass Lab whatever, the FirstWatt whatever. What was wrong with last year's amp? Is he still unsure. Does he make spectacular new discoveries in circuit design every year or so?
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- Thread starter Msheridanjj
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Of course comments like that made by Ralph Camden may tell us a lot about the poster but very little of value about the subject.
I have always had the impression that Nelson Pass is genuinely passionate about audio and that quite a bit of what he does is about satisfying his own curiosity and creative urges. And his efforts to promote DIY audio are commendable. I have never owned any of his designs but have always had a lot of respect for him
I don't rate amps (or anything else) here, so you're barking up the wrong tree. Also, please don't attribute things to me I didn't say. This is what I actually said: "Our ears are highly sensitive to many things, but distortion with program material is not one of them." That's entirely different than "If we can't hear distortion..."
I don't mean to be testy here, but if you refuse to read what I say and start rewording things, it's useless trying to have a discussion.
I've spent a good deal of time on line and in person with him, and would agree entirely.
The question I have is if distortion cannot be heard, or at least at Pass Labs rated 1%, then why does it matter?
I’ve read the comment that Subjectivists cannot both claim the following:
1) that differences between amps are so obvious one would have to have “cotton ears” not to hear it, and
2) that a Subjectivist can’t discern a difference in an ABX test because the differences are too subtle in a less than perfect environment of which a “perfect environment” seems to be a moving target.
Okay, that seems to be a fair critique.
Conversely for Objectivists it seems, at least in this thread, that they’d like both of the following to be true:
1) Pass Labs has an unacceptable amount of distortion at 1%, and
2) that no difference can be heard between a Pass Labs amplifier with this level of distortion and an amplifier with a much lower amount like the Purifi one mentioned in this thread for example.
If the latter is indeed true, then why is the distortion unacceptable? If it cannot be perceived by the listener’s hearing, then why does it matter at all? If the former is true because distortion of 1% alters the sound of the amplifier different than one deemed “straight wire with gain”, then how is that not the same as saying that some amplifiers sound different?
I’ve read the comment that Subjectivists cannot both claim the following:
1) that differences between amps are so obvious one would have to have “cotton ears” not to hear it, and
2) that a Subjectivist can’t discern a difference in an ABX test because the differences are too subtle in a less than perfect environment of which a “perfect environment” seems to be a moving target.
Okay, that seems to be a fair critique.
Conversely for Objectivists it seems, at least in this thread, that they’d like both of the following to be true:
1) Pass Labs has an unacceptable amount of distortion at 1%, and
2) that no difference can be heard between a Pass Labs amplifier with this level of distortion and an amplifier with a much lower amount like the Purifi one mentioned in this thread for example.
If the latter is indeed true, then why is the distortion unacceptable? If it cannot be perceived by the listener’s hearing, then why does it matter at all? If the former is true because distortion of 1% alters the sound of the amplifier different than one deemed “straight wire with gain”, then how is that not the same as saying that some amplifiers sound different?
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I dunno about you, but I can hear 1% distortion at most frequencies.
I don't think anyone has claimed that 1% THD is inaudible. The key seems to be that Pass looks for a distortion pattern that his customers enjoy.
There's a difference in audibility between pure tones and program material. We tend to be a lot less sensitive to the latter, which is why I have some skepticism about "distortion patterns" absent actual evidence for those claims.
In regard to Pass Labs specifically one of the most interesting listening tests I’ve read about is the one between Steve Zipser and Tom Nousaine where Zipser could not hear a difference between his Pass Labs monoblocks and a Yamaha integrated amp. The details are given here in ASR within this thread:
https://www.audiosciencereview.com/forum/index.php?threads/catalogue-of-blind-tests.8675/
This certainly seems to lend evidence to the position there is not an audible difference. However, if this is true, then doesn’t it also mean there’s really not much meaningful in the low distortion specs often lauded for amps with distortion ratings of a fraction of a percent? While such an achievement might be a nice technical accomplishment for the engineer making the amp, if the level is well below audible levels for a listener, then why is it even worthy of mention?
For example, Benchmark amps are much praised for their excellent measurements and in this specific case distortion level, or lack thereof. However, if a listener cannot hear distortion in any meaningful way beyond perhaps a test tone at 1% distortion, then that shows engineering prowess on Benchmark’s part, but why would it be a factor in a buyer’s purchasing choice? On the Harbeth User Group there seems to be more of a sentiment that since amplifier technology is a solved problem, one should focus on cost savings and buy something like a Yamaha S-701 or S-801, being an affordable product with sufficient power to power many speakers. Certainly from a cost perspective alone $800-$900 for the Yamaha is a much smaller expenditure than $5500-$6000 for a Benchmark amplifier and preamplifier.
There are of course other factors one can consider in the assessment and purchase of an amplifier such as customer support, product features, and product reliability for instance, but distortion level would seem to be one not worthy of considering unless audible. Then if that is the case, my question is at what levels has distortion been shown to be reliably audible with meaningful material, meaning content beyond test tones that a listener would enjoy in his or her regular life such as music, movies, TV programming, etc? I would think these tests and studies have been conducted so that manufacturers of these products can ascertain what will make an acceptable product consumers will buy.
https://www.audiosciencereview.com/forum/index.php?threads/catalogue-of-blind-tests.8675/
This certainly seems to lend evidence to the position there is not an audible difference. However, if this is true, then doesn’t it also mean there’s really not much meaningful in the low distortion specs often lauded for amps with distortion ratings of a fraction of a percent? While such an achievement might be a nice technical accomplishment for the engineer making the amp, if the level is well below audible levels for a listener, then why is it even worthy of mention?
For example, Benchmark amps are much praised for their excellent measurements and in this specific case distortion level, or lack thereof. However, if a listener cannot hear distortion in any meaningful way beyond perhaps a test tone at 1% distortion, then that shows engineering prowess on Benchmark’s part, but why would it be a factor in a buyer’s purchasing choice? On the Harbeth User Group there seems to be more of a sentiment that since amplifier technology is a solved problem, one should focus on cost savings and buy something like a Yamaha S-701 or S-801, being an affordable product with sufficient power to power many speakers. Certainly from a cost perspective alone $800-$900 for the Yamaha is a much smaller expenditure than $5500-$6000 for a Benchmark amplifier and preamplifier.
There are of course other factors one can consider in the assessment and purchase of an amplifier such as customer support, product features, and product reliability for instance, but distortion level would seem to be one not worthy of considering unless audible. Then if that is the case, my question is at what levels has distortion been shown to be reliably audible with meaningful material, meaning content beyond test tones that a listener would enjoy in his or her regular life such as music, movies, TV programming, etc? I would think these tests and studies have been conducted so that manufacturers of these products can ascertain what will make an acceptable product consumers will buy.
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MarkS
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Solid state amps have been essentially perfect since the 70s (at least). All this testing is meaningless. They all sound EXACTLY THE SAME. If you don't care about impressing yourself or others with technical specs, buy the cheapest that looks nice enough.
Me, I use a 10-year-old consumer-level Marantz 2-channel receiver and 16-gauge lampcord for speaker wire.
Me, I use a 10-year-old consumer-level Marantz 2-channel receiver and 16-gauge lampcord for speaker wire.
It does seem that an amp operating on the edge of audible distortion may well have some long term reliability concerns, i.e. that the distortion way well become audible.
I do agree with MarkS that any amp with significantly lower distortion (say <0.5% 20hz-20khz) should be chosen on the basis of power, features, looks, reliability, etc.
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I am going to continue to hammer on the nail that simple test tones may not give us the best test for hearing distortion.
The Benchmark is designed to reduce crossover distortion BTW - so some sort of test that has music continually requiring the amp to switch from A to B would be fun.
OTOH... speakers, people!
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