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Double Blind tests *did* show amplifiers to sound different

MakeMineVinyl

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A very PC, good marketing type answer. ;)
If you were designing and manufacturing amplifiers, what would your development cycle look like? It appears you're good with designing something, running it on an AP, then making them and shoving them out the door without any listening phase. Is this what you honestly would really do?
 

sergeauckland

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If you were designing and manufacturing amplifiers, what would your development cycle look like? It appears you're good with designing something, running it on an AP, then making them and shoving them out the door without any listening phase. Is this what you honestly would really do?

Possibly so, but any listening would only be as a final 'reality check' to make sure that nothing had been missed or misinterpreted in the measurements, and as part of the final 'signing off' procedure before production. I certainly wouldn't include listening tests as part of the design or development cycle, or indeed as part of the QA procedure before despatch.

S.
 

MakeMineVinyl

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Possibly so, but any listening would only be as a final 'reality check' to make sure that nothing had been missed or misinterpreted in the measurements, and as part of the final 'signing off' procedure before production..
But surely, it it measures perfectly, there is no point in any listening at all, no? ;)
 

SIY

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But surely, it it measures perfectly, there is no point in any listening at all, no? ;)
That was Peter Walker’s philosophy, other than listening to some test tones during development.
 

DSJR

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Quad in the days of Peter Walker was very much like that. PW only ever used components that met the specification required, and was criticised in the HiFi rags for not using the flavour-of-the-month capacitor or resistor. A whole industry sprung up, largely still going, modifying Quad amps to put back all the goodness PW left out. :facepalm:

Much the same thing happens with loudspeakers where a specific marketing point is made of the capacitors used in the crossover, and providing bi-wire terminals.

S.

Ummm,

Have you seen (then) ten year old 303's and 405's made in PW's time with 'adequate' components? Supply caps with leaky 'mountains' on top of them (or dripping down onto the board underneath in the case of an early 303 (why they ended up standing said caps up in later samples), 34 preamps and FM3 runers with supply caps leaking over the main board they're soldered to, at the very least bulging in the case of my FM3 and so on? Maybe 'better' and more durable caps weren't available to the UK market then, but it's a real situation and in fairness, update kits a la Dada, do seem to use sensible modern replacement parts by and large which generally don't dramatically alter the original design. I suspect we in the UK weren't best serviced with decent quality electrolytics - or the designers didn't over-specify them at the time, I don't know...

I read an interview with Peter Walker some time back, where he readily admitted to 'listening' to his amps in development. What he was 'listening for' though, was audible distortion that got in the way and, back in those days, tweaking the designs to push said audible distortions as far out of the way as possible. I gather it wasn't so easy then..
 
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MakeMineVinyl

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That was Peter Walker’s philosophy, other than listening to some test tones during development.
Just curious, have you ever worked for an amplifier manufacturer as a designer - and your name is on the sign-off when the things are deemed ready to go out the door? You just tell your boss that "I've measured it - it is perfect - so go to hell cuz that's the hill I've decided to die on"!
 

SIY

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Just curious, have you ever worked for an amplifier manufacturer as a designer - and your name is on the sign-off when the things are deemed ready to go out the door? You just tell your boss that "I've measured it - it is perfect - so go to hell cuz that's the hill I've decided to die on"!

Amplifiers for audio, no. Other high volume mission-critical electronics, yes.
 

MakeMineVinyl

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Maybe 'better' and more durable caps weren't available to the UK market then, but it's a real situation and in fairness, update kits a la Dada, do seem to use sensible modern replacement parts by and large which generally don't dramatically alter the original design. I suspect we in the UK weren't best serviced with decent quality electrolytics - or the designers didn't over-specify them at the time, I don't know...

I've got amplifiers, pre-amplifiers and such which are well over 60 years old which have no issues whatsoever with components breaking down. So good components were available.
 

sergeauckland

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Ummm,

Have you seen (then) ten year old 303's and 405's made in PW's time with 'adequate' components? Supply caps with leaky 'mountains' on top of them (or dripping down onto the board underneath in the case of an early 303 (why they ended up standing said caps up in later samples), 34 preamps and FM3 runers with supply caps leaking over the main board they're soldered to, at the very least bulging in the case of my FM3 and so on? Maybe 'better' and more durable caps weren't available to the UK market then, but it's a real situation and in fairness, update kits a la Dada, do seem to use sensible modern replacement parts by and large which generally don't dramatically alter the original design. I suspect we in the UK weren't best serviced with decent quality electrolytics - or the designers didn't over-specify them at the time, I don't know...
And yet, and yet, My son has an original, completely unmolested Quad 303 working perfectly, and a Quad 44 ditto.

I have several amplifiers from the 1970s all working fine with original parts, none of them 'boutique', just decent ordinary commercial parts.

So, no, I don't see Dada's mods being of any value.

S.
 

MakeMineVinyl

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As a real world example of things I have listened for on a current design, there is a sleep mode where in the absence of signal for 10 minutes, the amplifier goes into a low power mode. Yes, the threshold for "waking up" the amplifier is specified, but how does that actually sound when playing, say a real movie with extended soft dialogue? Does the amplifier clip off sound when it enters sleep? Does it clip off sound when it wakes up? Does the amplifier make strange noises or pops when it wakes up/goes to sleep? These things can only be determined by critical listening. If I just measured things, and shoved it out the door, I'd be toast.
 

sergeauckland

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But surely, it it measures perfectly, there is no point in any listening at all, no? ;)
Generally no, but usually part of the sign-off procedure is to show the product to Marketing and Sales and possibly finance, where a set of test results won't impress. A listening demo will be a lot more convincing, and anyway, it's always possible that a measurement was made incorrectly, and/or a fault has occurred, so a listening test as a final 'reality check' is sensible. What I don't see as sensible is designing by ear, changing stuff and listening to the results. That to me is a total nonsense, although is ostensibly the method used by some boutique manufacturers, especially some Japanese valve gurus, and one or two UK manufacturers.

S.
 

MakeMineVinyl

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Amplifiers for audio, no. Other high volume mission-critical electronics, yes.
Well, maybe actually do some work with a real amplifier manufacturer, and see how far not listening at all gets you?
 

MakeMineVinyl

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Generally no, but usually part of the sign-off procedure is to show the product to Marketing and Sales and possibly finance, where a set of test results won't impress. A listening demo will be a lot more convincing, and anyway, it's always possible that a measurement was made incorrectly, and/or a fault has occurred, so a listening test as a final 'reality check' is sensible. What I don't see as sensible is designing by ear, changing stuff and listening to the results. That to me is a total nonsense, although is ostensibly the method used by some boutique manufacturers, especially some Japanese valve gurus, and one or two UK manufacturers.

S.
Just tell them but dammit, I measured it and it is perfect - you can all go away because I know what's best, surely? Real resume enhancing......
 

sergeauckland

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But dammit, I measured it and it is perfect - you can all go away because I know what's best, surely? Real resume enhancing......
If it measures perfect, then it is perfect, and indeed, you can all go away!

If you want to put it into a box hewn from the solid and polished on the thighs of virgins, then fine, but the electronics is not being changed.

S.
 

MakeMineVinyl

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If it measures perfect, then it is perfect, and indeed, you can all go away!


S.

Your future as an amplifier designer is guaranteed (to be short lived). But at least you can say you had it your way...while it lasted. Just don't expect me to fly on an airplane you designed. o_O
 

DSJR

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And yet, and yet, My son has an original, completely unmolested Quad 303 working perfectly, and a Quad 44 ditto.

I have several amplifiers from the 1970s all working fine with original parts, none of them 'boutique', just decent ordinary commercial parts.

So, no, I don't see Dada's mods being of any value.

S.

They were to my 33 preamp in comparison to a known transparent reference in terms of noise and so on. I'm glad you have an entirely original 303 still working well - mine was totally and sensitively rebuilt by a former owner so I didn't/couldn't do anything to it. My experience - honestly - is that not all do and they've not been owned by metal-heads either.. Both 405's I had (one known since new) in the late 80's/early 90's had absolutely knackered supply caps, which were replaced along with the mk2 board update (the 405 went through several board layout changes before the mk2 came out).

Apologies, totally off topic. All I'd politely ask is that you don't dismiss *some* of these updates out of hand as UK manufacturers didn't 'seem' to have the component longevity that say, my vintage Crowns (used domestically to be fair) have and my times in the domestic audio industry were very 'enlightening,' believe me.
 

NTK

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Your future as an amplifier designer is guaranteed (to be short lived). But at least you can say you had it your way...while it lasted. Just don't expect me to fly on an airplane you designed. o_O
That's what separate good engineers from average ones.

Do you think those designing the James Webb telescope get to "verification test" a "prototype" by launching it to space to verify that it works in its intended operating environment before "shipping"?
 

MakeMineVinyl

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That's what separate good engineers from average ones.

Do you think those designing the James Webb telescope get to "verification test" a "prototype" by launching it to space to verify that it works in its intended operating environment before "shipping"?
No, but I don't believe they just throw up their first design either.
 

DSJR

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I've got amplifiers, pre-amplifiers and such which are well over 60 years old which have no issues whatsoever with components breaking down. So good components were available.

I have to be cheeky with respect and apologies - any UK made gear in that?

Interesting with B&O for a while. Their 60's builds seemed everlasting yet the stuff from the 70's onwards could be very troublesome, with boards full of bulging caps and so on. Maybe they just under-specified them so not a component issue perhaps. A few UK higher end makers did the same and this is where 'our' amp-servicing thing came from - I've seen the results of this in my time, although more modern gear seems a heck of a lot better in fairness..

Best I leave off as I'm drifting as usual...
 
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