In article , Trevor Wilson
wrote:

"Jim Lesurf" wrote in message
...


Still have a slipstick as well.. ;-

**Me too. I have the finest one ever made. The mighty Faber Castel
2/83N.

Mine is just a cheap Ricoh (Japanese) one. Bought it for 6th form and
university. The curious thing about it is that it is made from wood with a
plastic facing for the scales! Thus I can claim to have an analogue
computer[1] made of wood. :-)

[1] OK, its not programmable, so not really a 'computer'. However it never
gave me a blue screen... ;-

Slainte,

Jim

--
Electronics http://www.st-and.ac.uk/~www_pa/Scot...o/electron.htm
Audio Misc http://www.st-and.demon.co.uk/AudioMisc/index.html
Armstrong Audio http://www.st-and.demon.co.uk/Audio/armstrong.html
Barbirolli Soc. http://www.st-and.demon.co.uk/JBSoc/JBSoc.html

Good morning, Jim, and indeed a fine sunny one. I'll see if I can address your
comments.
I can see that component changes might be more noticable with such a valve amp
than with many SS amp designs.

I don't build SS, but I would guess that you are right about the factors
involved - low or zero global feedback, transformers, variability within valves
being greater than between chips and probably also the larger voltage
differences within circuits that substitutions make, compared to regulated SS
voltage rails.

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.

This is interesting, because I'm sure many people like valve amps because they
CAN make audible changes by swapping componants. This gives them an interactive
role in their audio passion, which they appreciate since it gets them more
involved. I'm sure I don't need to point out that 'interactive' is one of the
buzz popular appeal subjects of recent years.

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

How could a set of notes 'prove' this?

Exactly, I was being ironic. I thought my ironies were more transparent!

I'd be interested to know how you verify or test your own perceptions in
this area

Being 'lost in space' is part of the creative process e.g. it would be second
in a simple four stage model consisting of Orientation, Incubation, Inspiration
and Verification, and could well be quite anarchic in nature. Inspiration would
signify that some of the variables looked very promising, so this would then
become the 'breadboard' or prototype. Verification could take different forms
depending on the requirements. In a DIY amp, it may be sufficient that it
sounds good to the builder, with the obvious proviso that it should be safe and
stable. For a production model clearly more verification and safety testing
would be required, but I'm strictly talking DIY here. The experienced amateur
builder would, however, not be happy with 'sounds good'. He/she would want to
know as much as possible WHY a componant change made a difference, and further
than that how it could be repeated in different circumstances. One way to do
this would be to build an infinite number of prototypes and make careful notes.
This is exactly what most inventors did - e.g. the Wright brothers with their
many prototype 'planes. At a later stage, hopefully, would come theory and
equations (as with aviation models) but the DIY builder may largely work by
trial and error. Not to be dismissed out of hand - it has its merits. If I need
a set of scope measurements and distortion tests for a circuit I go down the
road to my designer friend who designs commercial products and has a proper
bench setup. I have a scope but using it is still on the 'to do' list of
projects. So my verification is partly subjective and partly intelligent trial
and error and careful notes of results achieved, voltages, componants, etc,
tests which I do with a multimeter and analyse in Excel, using equations
derived from books like Morgan Jones, Menno van der Veen etc and data on
Duncanamps (valve data, power supplies) and other audio sites. I also have a
valve tester to test the valves I use to see how they perform, so I at least
know that.

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

This is true of so many things in life - I'm sure we could think of numerous
examples. I wouldn't even try to claim I'd eliminated all uncontrolled
variables, though one does try to use as much methodology as one can.



=== Andy Evans ===
Visit our Website:- http://www.artsandmedia.com
Audio, music and health pages and interesting links.

When you claim that changing a resistor type changes the performance of an
amplifier, then you are talking engineering

You could take it any way you want - engineering, deductive methodology,
subjective aural impressions etc etc. YOU want everything to be engineering
because this is the area YOU are comfortable with, and judging by the evidence
very uncomfortable outside of.

=== Andy Evans ===
Visit our Website:- http://www.artsandmedia.com
Audio, music and health pages and interesting links.

In article ,
Jim Lesurf wrote:
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 one. Generally, when you try something, you've got a pre-conceived
guess as to the end result. Relying on your 'ears' to hear that 'change'
is a pointless exercise.

--
*Upon the advice of my attorney, my shirt bears no message at this time

Dave Plowman London SW 12
RIP Acorn

In article ,
Andy Evans wrote:
Oh yes - what do you want to know, my IQ? I'm a psychologist, I can tell
you.

Then you know perfectly well how easy it is to fool the 'ear', and
apparently make a living out of this.

--
*The modem is the message *

Dave Plowman London SW 12
RIP Acorn

On 15 Jun 2004 09:10:02 GMT, ohawker (Andy
Evans) wrote:

When you claim that changing a resistor type changes the performance of an
amplifier, then you are talking engineering

You could take it any way you want - engineering, deductive methodology,
subjective aural impressions etc etc. YOU want everything to be engineering
because this is the area YOU are comfortable with, and judging by the evidence
very uncomfortable outside of.

=== Andy Evans ===
Visit our Website:- http://www.artsandmedia.com
Audio, music and health pages and interesting links.

I really hope it isn't subjective aural impressions.

As a psychologist you are well aware (and wary) of the huge
differences that exist between perception and fact. But of course in
your posts you weren't talking perceptions of difference - you were
talking about differences. So you conducted properly proctored double
blind tests of the supposed "differences" before making your claims.

Didn't you.

d
Pearce Consulting
http://www.pearce.uk.com

you weren't talking perceptions of difference - you were
talking about differences. So you conducted properly proctored double
blind tests of the supposed "differences" before making your claims.

clearly if a resistor is 100 ohms that's what it IS. however, it is possible
that resistors sound different (PLEASE don't refer to me here, refer to
hundreds of posts on audio newsroups by other people including designers and
amp builders). So in the case that they SOUND different, then they do so
through our aural perception, so isn't it axiomatic that this includes the
dimension of perception? Please don't suggest that everyone double blind tests
every single componant they use - yes, we'd all like that luxury but nobody can
do so in practice except industry professionals whose time is already paid for,
and even then it's the exception not the rule.




=== Andy Evans ===
Visit our Website:- http://www.artsandmedia.com
Audio, music and health pages and interesting links.

Generally, when you try something, you've got a pre-conceived guess as to the
end result. Relying on your 'ears' to hear that 'change' is a pointless
exercise

I don't see that these statements follow. Yes, you may have a hunch how
something will turn out, but if you are a conscientious experimenter you will
factor in that you have a hunch, (snip nice story about Freud's original
methods of deduction) and in any case you may just as easily be surprised at a
result you don't expect. To go on from this and say "Relying on your 'ears' to
hear is pointless" seems not only redundant to the factoring in of bias
process, but something of a self-contradiction.

=== Andy Evans ===
Visit our Website:- http://www.artsandmedia.com
Audio, music and health pages and interesting links.

Then you know perfectly well how easy it is to fool the 'ear',

Not only the ear - the D-Day landing site was deliberately devised to fool the
Germans, who thought it was logical that the British would choose a shorter
crossing. there are numerous examples.

"and apparently make a living out of this". Are you suggesting I make a living
from fooling peoples' ears? Is there a word for
"a-person-who-makes-a-living-from-fooling peoples'-ears"? Tell me
more...........

=== Andy Evans ===
Visit our Website:- http://www.artsandmedia.com
Audio, music and health pages and interesting links.

On 15 Jun 2004 09:57:47 GMT, ohawker (Andy
Evans) wrote:

you weren't talking perceptions of difference - you were
talking about differences. So you conducted properly proctored double
blind tests of the supposed "differences" before making your claims.

clearly if a resistor is 100 ohms that's what it IS. however, it is possible
that resistors sound different (PLEASE don't refer to me here, refer to
hundreds of posts on audio newsroups by other people including designers and
amp builders). So in the case that they SOUND different, then they do so
through our aural perception, so isn't it axiomatic that this includes the
dimension of perception? Please don't suggest that everyone double blind tests
every single componant they use - yes, we'd all like that luxury but nobody can
do so in practice except industry professionals whose time is already paid for,
and even then it's the exception not the rule.




=== Andy Evans ===
Visit our Website:- http://www.artsandmedia.com
Audio, music and health pages and interesting links.

Oh Andy! I really thought that maybe you were a worthy opponent. I
even thought that maybe you understood something of your primary skill
- psychology. This reply makes it clear that you are as clueless in
that discipline as you are in engineering. You have no idea of how
sighted bias operates, and you compound it by suggesting that a demand
for a double blind test for something you perceive as different has
some sort of logical extension to double blind testing things you
don't. Do you really not see the ridiculousness of this premise?

So you have come to this group with absolutely nothing other than some
spurious, random, baseless claims. Did someone tell you that
audiophiles were all gullible dupes who could be conned out of a few
quid this way? Sorry, we simply aren't that dim (as unfortunately you
have now proven yourself to be beyond all doubt).

A few posts ago I offered a deal whereby I wouldn't lecture you on
psychology. Sorry. I was mistaken. You need lecturing in that subject
possible more than you do in engineering.

d
Pearce Consulting
http://www.pearce.uk.com