In article , Andy Evans
wrote:
The moral of this tale is that if you want to make sure nobody can
disagree with you, just say stuff that is devoid of any meaning.

OK, Don. you are by your own admission a consultant and this is a thread
about valve amplifiers. What I propose is that you give me a selection
of your own valve amplifier circuit designs

Is there a reason to limit this to valve amplifiers? If not, why not expand
it to using SS designs as a basis for camparing the (possible) audible
differences between components?

I am curious about this as most of my own work/experience has been in SS
designs. Hpowever it is my understanding that valve amps (particularly
older designs) tend to be typified by factors like having low overall
feedback, valve microphony, and the problems of output transformers. Given
these effects I can see that component changes might be more noticable with
such a valve amp than with many SS amp designs. However for the same
reason I might personally tend to prefer a SS design precisely because it
might give less scope for component variations having an audible effect.


with your detailed construction notes which prove that substituting
componants has no effect on the sound.

How could a set of notes 'prove' this? Are you perhaps using 'prove' when
you may mean 'evidence' or 'personal impression'? You might percieve a
difference, but be mistaken. Somone else might fail to percieve a
difference, but simply have missed it. Neither can clearly be said to
'prove' anything beyond the report in itself.

Or do you mean notes on measured results or something like a double blind
series of comparisons?

I'd be interested to know how you verify or test your own perceptions in
this area. In my experience it is one thing to have an impression that a
change has had an effect. It is something else to test this over a period
of time in a way that can reliably rule out uncontrolled variables or
variations in hearing. How do you do this when coming to your conclusions?

In return I will give you a selection of my own valve amplifier circuit
designs with my detailed construction notes on the diverse effects of
substituting componants. You are welcome to breadboard my circuits with
the relevant parts to check whether your own ears confirm the effects I
have found. That sounds reasonable doesn't it? Let's put this to the
test.

Who is paying for the components (and the time and testgear)?... ;-

Slainte,

Jim

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