In article , Rob
wrote:
Jim Lesurf wrote:
In article , Rob
wrote:
Jim Lesurf wrote:

My concern (such as it is) is simply this: I maintain different
modern SS amplifiers can sound different.

It is essentially self-evident that they 'can'. Indeed, you can choose
to design two amps so that they do. However when people have done
tests on amps that were not specifically designed to do this and which
were designed to amplify, then they tend to be able to distinguishg
one from another. i.e. they are found not to 'sound different'.

But if you choose a design which is - either by deliberate choice or
incompetence - making the output sufficiently different from a scaled
version of the input then it may well 'sound different'.


I wouldn't mean to use or buy an incompetent amplifier. I take it you'd
consider anything from the big names (Sony, Cambridge, Rotel, NAD, Quad,
Behringer etc) to be competent - in the sense that if they did turn out
to be incompetent you'd be surprised.

Actually, I have long ceased being 'surprised' by what makers do at times.
:-) Hence I'd wary of placing too much reliance on the name badge.
Particularly now that various brands are no longer owned by the original
people who built them up to have a reputation for quality.

e.g. Despite Sony being a regarded name I recently tried a DVD recorder
from them. It had a cooling fan that was so loud that it was distracting
when listening to dialogue on items recorded. This is absurd and needless,
yet when I asked a local Sony center their reaction was 'they all do it'.
They seemed not to think it was a problem, and clearly had no idea that
quiet fans can be bought. Perhaps they think everyone is too busy looking
at the pictures to notice the sound of a helicopter accompanying it. ;-

The above is nothing to do with amps per se. But it shows that some
companies end up being run by suits, and have development engineers who
just produce what they are told by the suits and go home with their
paychecks. The spec says nothing about the fan not making a loud noise, so
this cheap one is fine...

I've also repeatedly witnessed companies who bring out 'new' products
distinctly worse than the ones they'd made a year or two before. Different
suits and a different R&D team. No internal communications. No clue.
The relevant suits and engineers are often isolated from the public
and getting contact with them is almost impossible in practice.

[snip]



Well you may be "pretty sure", but the problem is that many people in
the past have been "pretty sure" of similar claims - but then failed
to be able to do what they were "pretty sure" of when tested on the
basis of the sounds in a matter that excluded well known and
uncontentious sources of differences. Thus your belief is simply a
statement of faith at this point, not evidence. Given all the previous
failures it isn't clear why anyone would be wise to take your belief
seriously *unless* you put it to such a test and showed you can do
what you believe. Until then...


Well, it's the result of experience. Many people claim similar
experiences. As 'evidence' of 'fact' I'd agree that it's flimsy. Faith?
Belief with reason? Yes, we agree.

Many people claim many things - often contradicting one another in the
process. People believe all kinds of things. And tests in this area have
often shown that what someone believes they can do, they are unable to
show they could do when tested. To the point where many reviewers decided
to stop participating in such tests and instead behave as if they'd never
happened.

There are simply too many ways for someone to decide that a 'difference'
they hear is for one reason when in reality it is for another that hasn't
occurred to them, or they have made a simple mistake. Hence 'evidence'
comes from tests which are designed to deal with these problems and produce
results whose reliability and relevance can be assessed by others who
understand the problems. This means people can decide on the basis of the
evidence returned, and avoids having to accept what they are told in a
claim which may be worthless nonsense.



Perhaps if I explain it this way - it's not what people think and say,
but why they think and say it, which is of most importance. Do you
*know* (or even have the vaguest idea) why people (like me) experience
these 'physical world anomalies'? I certainly don't *know*.

What we (i.e. various engineers and experimental scientists who have
studied these topics seriously and engaged in tests, etc) 'know' (from both
experience and study) is that there are many pitfalls and other effects
that can cause people to ascribe the wrong 'reason' to what they think they
heard. Thus claims by people who don't know and understand the 'history' of
this topic nor the science tend to be greeted with sighs and groans. This
is why some of the reactions you get are dismissive or sharp. It is a loop
some of us have been round countless times for decades.

I get involved partly to try and point out to people that there is a great
deal on these topics which has aready been covered, and that the problems
of claims are also not new. Partly because I am open to the idea that every
now and then someone will come up with a genuinely 'new' idea or discovery.
Alas, this openness seems not to pan out in general... it does mean I
get bored at times at seeing the same old claims with the same lack of
a reliable basis or understanding by the claimant of the problems.

None of the above means 'all amps sound the same'. Nor that 'they all
sound different'. But it does means that claims which are not based
on taking the above into account are generally worthless. I can take
an interest in discussing them here as I do so for the reasons I give.
But most professionals in, say, the AES or IEEE would regard discussions
on this topic as a waste of breath, and expose you to abuse from people
who can't bear the idea that what they claim may simply be wrong. Look
back a few decades and you can find out why...




Again, Serge guided me on this. This issue has been mentioned many
times. 'Most' means virtually all modern SS amps that meet certain
criteria (1).

On such a basis the evidence supports what Serge has been saying. If
you wish to contend with that you will need relevant assessable
evidence for people to take you seriously. Given the history of this
topic people will regard claims of what you are "pretty sure" of as no
more than an unsupported belief of the kind which has in the past
repeatedly been shown to have no foundation.


Again, we've trawled through all of this. It *is* supported, albeit not
with the scientific test *you* require.

Afraid not. 'Support' does not mean that 'many people have the same
opinion'. Afraid you are still thinking in 'social science' terms, not
those of science and engineering. Nor does 'support' mean a result
which may be for many other well-established reasons which were ignored
by the claimant. Distinction between an observation and claiming the
*reason* for it. Someone may hear a 'difference' when they changed one
amp for another - but that does not support the amps being the *reason*
*unless* the other factors which can cause a change are dealt with.

Your approach would mean all views are 'supported' which makes 'support'
worthless since the 'supported' views conflict. Thus the need for boringly
tedious things like an appropriate test method to deal with the various
types of factors which otherwise cause misleading results, and to produce
assessable evidence rather than bald statements of 'faith'. What matters is
support by reliable, assessable, *evidence*. (This means both the test
method and the results.)

I am not talking about one single form of 'scientific test'. I am talking
about the approach being relevant and able to be shown to be capable of
producing reliable results rather than simple, well known, errors. I am
also talking about people knowing about, and understanding, the many
tests and sets of evidence which already exist and have largely settled
these matters for most professional engineers and academic scientists.

The point is that there are many well-known pitfalls and factors which can
produce 'differences' which have nothing to do with changing one amp for
another. Unless a comparison deals with these a claim that a change was due
to one *amp* 'sounding different' to another is worthless. It also is a
waste of time given that the pitfalls, and ways to deal with them, are well
known to those who have studied the topic seriously. Given this it is
perhaps understandable when some become irritable at seeing repeated claims
based on ignorance or dismissal of these factors. It is also why I've come
to expect evidence rather that assertions of faith or confidence.

Slainte,

Jim

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