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Amplifiers and the End of Science


George 47
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9 hours ago, rabski said:

One of my favourite forms of music.

I can't reproduce it faithfully, but the sub does manage the really low ocatves very well and the rest does a reasonable job. Most of the Bach organ works sound quite reasonable here, I am pleased to say. As does the stunning Gillian Weir recording of Messiaen's L'ascension. Probably the most wonderful piece of music ever.

I'll search that recording out, thanks.
Saint Saens' organ symphony is one with infra bass down to 16Hz - an impressive piece of music, even if the lowest stuff is not reproduced.
 

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On 9/4/2017 at 12:43, Valvebloke said:

Oh, I never said that what we hear is understood ;). Hearing involves our minds. Minds are far from completely understood. It has been proved countless times though that we can simply be wrong about what we think our senses are telling us.

VB

I agree, I was being facetious ;-) 

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On 9/2/2017 at 12:22, SergeAuckland said:

This quote says it all for me:-

"In the end, the subjective experience is what our customer is looking for. Our taste in sound may not appeal to everyone, but it's what we have to work with, and we only need a small segment of the market to be successful. I don't neglect the measurements; I put them to work."
 

It's pretty much the antithesis of what I've always looked for in audio design, the complete absence of a 'sound' that you can like or dislike. 

Peter Walker described the ideal amplifier as "A piece of wire with gain"  then went on to explain why a piece of wire wouldn't work, but no matter, a worthy aim as far as I'm concerned.

Of course all this was at a time when it was accepted that wires didn't have a sound.........

S.

It's what most designers work for surely?  They are also the cause of their own problems .. Walker designed the 405 to work into 8 ohms - if you ran it into less the power dropped and it sounded not good .. so they reworked it to come up with the 405-2 that would work properly down to 4 ohms.  I have never heard of an engineer trying to "voice" an amp (as some supposedly do with loudspeakers although I might suggest that it is not so much voicing with loudspeakers  e.g. the hump at 125 hertz or thereabouts on the LS35A to give an impression of bass)  BUT it is strange how amplifiers with a virtually ruler flat response and minimal distortion and ability to drive loads can sound so different. 

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There are lots of things you can do to "voice" amplifiers. Bit of a black art IMO, but really quite surprising what can be achieved by tweaking some resistor values one way or another. As an aside i don't think anyone would agree that a quad II sounds like a 405, although maybe mr walker did? I do wonder about the hearing sometimes...  Stan Curtis has interesting things to say about amplifier voicing, but I am not sure if he has all his outpourings accessible in one place.

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16 hours ago, JamPal said:

I agree, I was being facetious ;-)

James 

you know such behaviour is banned encouraged on the 'wam

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5 hours ago, dave said:

As an aside i don't think anyone would agree that a quad II sounds like a 405, although maybe mr walker did? I do wonder about the hearing sometimes...

You're absolutely right to wonder about the hearing. It's dreadfully unreliable as a tool for objective assessment of electronic performance.

The example of the Quad 405 vs the Quad II (and the Quad 303) was precisely the combination that no-one could tell apart in James Moir's tests once the listeners couldn't see which amplifier they were listening to. Some folks in the professional reviewing community, whose livelihoods depended on people believing that they (the reviewers) could hear differences, objected to details of Moir's tests. They cared so much about it that they decided to repeat the tests themselves, this time using a Quad 405, a TVA Export (80W/ch valve amp) and a Naim NAP250. Sure enough, before the tests the reviewers were convinced that these were three very differently sounding amps. But again once they were working blind they couldn't tell them apart (two out of the eleven participants just "scraped home" in the test, the rest did no better than chance). In my view it was commendably honest of them to say so in print. The results of the latter tests are reported in Hi-Fi News and Record Review Vol 23 No 11 (Nov 1978).

VB

EDIT: You can read the Moir paper here http://www.keith-snook.info/wireless-world-magazine/Wireless-World-1978/Valves versus Transistors DCD.pdf.

Edited by Valvebloke
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8 hours ago, Valvebloke said:

You're absolutely right to wonder about the hearing. It's dreadfully unreliable as a tool for objective assessment of electronic performance.

The example of the Quad 405 vs the Quad II (and the Quad 303) was precisely the combination that no-one could tell apart in James Moir's tests once the listeners couldn't see which amplifier they were listening to. Some folks in the professional reviewing community, whose livelihoods depended on people believing that they (the reviewers) could hear differences, objected to details of Moir's tests. They cared so much about it that they decided to repeat the tests themselves, this time using a Quad 405, a TVA Export (80W/ch valve amp) and a Naim NAP250. Sure enough, before the tests the reviewers were convinced that these were three very differently sounding amps. But again once they were working blind they couldn't tell them apart (two out of the eleven participants just "scraped home" in the test, the rest did no better than chance). In my view it was commendably honest of them to say so in print. The results of the latter tests are reported in Hi-Fi News and Record Review Vol 23 No 11 (Nov 1978).

VB

EDIT: You can read the Moir paper here http://www.keith-snook.info/wireless-world-magazine/Wireless-World-1978/Valves versus Transistors DCD.pdf.

I don't necessarily disagree, but I would like to see that test repeated with speakers capable of high definition. I suspect the results might not be quite the same.

Generally, I tend to the 'it does actually all sound the same' school of thought. However, I have had a 405 and a Quad II here and I have to say that with a suitable decent (high resolution) source and decent speakers (ironically, ESL57s) they don't. I'm happy to state that I would find it hard to determine which was which, but equally I'd be happy to state that there are audible differences.

Peter Walker was great at marketing, but let's not get carried away by the hype. If he really thought that Quad IIs were perfect, why then would he have built and marketed numerous amplifiers subsequently?

Why make the 405 if the 303 was a 'straight line gain' amplifier?

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9 minutes ago, rabski said:

... but I would like to see that test repeated with speakers capable of high definition ...

The Moir test was done with Yamaha NS 1000s at the insistence of one of the listening panel. Moir doesn't say who, but Martin Colloms, who organised the HFN repeat tests, says of them "If there are any doubts that low distortion is possible from a loudspeaker system, the results obtained for the classic, pure piston Yamaha NS 1000 should dispel them" (I'm quoting from the 6th edition of his 500-plus page tome High Performance Loudspeakers dated 2005). That said, he does like ESLs even more.

Someone ;) asked the "Why make another amp once you've achieved sonic perfection ?" question pages and pages ago (Sept 4th 17:30). Serge provided an answer a couple of posts later to which I can't add anything I'm afraid.

VB

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2 hours ago, rabski said:

I would like to see that test repeated with speakers capable of high definition. I suspect the results might not be quite the same.

Exactly - there's a lot out there that 'doesn't make any difference', until you hear it in a revealing system!

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6 minutes ago, robbyd said:

Exactly - there's a lot out there that 'doesn't make any difference', until you hear it in a revealing system!

They don't get much more revealing than NS1000s.

S

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They probably do! :D

Edited by robbyd
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12 hours ago, Valvebloke said:

You're absolutely right to wonder about the hearing. It's dreadfully unreliable as a tool for objective assessment of electronic performance.

The example of the Quad 405 vs the Quad II (and the Quad 303) was precisely the combination that no-one could tell apart in James Moir's tests once the listeners couldn't see which amplifier they were listening to. Some folks in the professional reviewing community, whose livelihoods depended on people believing that they (the reviewers) could hear differences, objected to details of Moir's tests. They cared so much about it that they decided to repeat the tests themselves, this time using a Quad 405, a TVA Export (80W/ch valve amp) and a Naim NAP250. Sure enough, before the tests the reviewers were convinced that these were three very differently sounding amps. But again once they were working blind they couldn't tell them apart (two out of the eleven participants just "scraped home" in the test, the rest did no better than chance). In my view it was commendably honest of them to say so in print. The results of the latter tests are reported in Hi-Fi News and Record Review Vol 23 No 11 (Nov 1978).

VB

EDIT: You can read the Moir paper here http://www.keith-snook.info/wireless-world-magazine/Wireless-World-1978/Valves versus Transistors DCD.pdf.

The problem here is that was two tests that's not enough to come to any conclusion you need to do it hundreds of times probably thousands. So few Abx tests are statistically insignificant but still used to discredit the people that say amplifiers. cables etc... sound different. The problem is no-one is going to do full scientific research into this phenomenon because the cost would be ridiculous for something so trivial and unimportant to the advancement of science we have more pressing things to put the money too. So for me I'll enjoy the differences I perceive because its a pointless merry-go-round argument that's lasted 50 bloody years. 

https://en.wikipedia.org/wiki/ABX_test

Edited by whizzkid
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33 minutes ago, whizzkid said:

... is that was two tests that's not enough to come to any conclusion ...

It wasn't two tests, it was two sets of tests. In the second set the first round was conducted by a panel of seven people listening for a whole day, divided into mutliple repeats of three sets of 20-minute sessions. In the second round thirteen people listened individually to twelve 4-minute music sections each. Martin Colloms is a clever guy. He understands the details of statistical significance and he wrote those details up in the HFN article.

Here's the conclusion that you can come to. There was a group of professionals who made a living by asserting that there were large differences, note LARGE differences, between the sound of amplifiers. These differences were sufficiently large that they could be judged and reported on in detail, note IN DETAIL - not just "This is amp A and that one's amp B", but, for example, "A is more more cold, has more PRAT, presents a better-defined soundstage whereas B is more warm, more musical, delivers a greater sense of close-in presence etc, etc ). These differences could be established reliably, month in month out, by carrying out careful but relatively straightforward listening tests. It was worth reporting the results in magazines to ordinary listeners because the differences were so clear that not just professionals but pretty much everyone who bought the mags would be able to hear them perfectly well. They were not vague or marginal. They were big and important. Except when the first blind test was done people couldn't even tell the amps apart. And when the test was redesigned and carried out again by the professionals themselves they still couldn't tell the amps apart. That's going to need some explaining away.

VB

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I would be happy to re do that test (in a few years!!), for entertainment purposes. I have some NS1000s and i have got a quad II (on the back burner at present,) rebuild in progress. don't have a 405 or a 303 yet...... It is my suspicion that there are some environmental and system issues that are not optimal for allowing the character of the amplifier to be heard.

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It wasn't two tests, it was two sets of tests. In the second set the first round was conducted by a panel of seven people listening for a whole day, divided into mutliple repeats of three sets of 20-minute sessions. In the second round thirteen people listened individually to twelve 4-minute music sections each. Martin Colloms is a clever guy. He understands the details of statistical significance and he wrote those details up in the HFN article.
Here's the conclusion that you can come to. There was a group of professionals who made a living by asserting that there were large differences, note LARGE differences, between the sound of amplifiers. These differences were sufficiently large that they could be judged and reported on in detail, note IN DETAIL - not just "This is amp A and that one's amp B", but, for example, "A is more more cold, has more PRAT, presents a better-defined soundstage whereas B is more warm, more musical, delivers a greater sense of close-in presence etc, etc ). These differences could be established reliably, month in month out, by carrying out careful but relatively straightforward listening tests. It was worth reporting the results in magazines to ordinary listeners because the differences were so clear that not just professionals but pretty much everyone who bought the mags would be able to hear them perfectly well. They were not vague or marginal. They were big and important. Except when the first blind test was done people couldn't even tell the amps apart. And when the test was redesigned and carried out again by the professionals themselves they still couldn't tell the amps apart. That's going to need some explaining away.
VB

Excellent post, sir. I'm sitting on the fence on the underlying argument about whether there may be audible differences between (in spec etc) amplifiers; part of me knows I've heard them and another would be delighted to know that my Arcam solid state kit will see me into my dotage because I won't hear anything (solid state) better. Well-considered and carefully constructed posts like this swing me strongly to the latter, which is nice.
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