Digital volume control question....
 

"Jim Lesurf" wrote

Overall, yes, that seems fine to me. However the snag is that some people
may have not followed the context. What you said above makes sense to me,
but we have the situation where we may have to re-explain this context to
avoid confusions. Plus my impression that the use of 'perceive' in
situations like this has more than once led to arguments at
cross-purposes.
Indeed, once people start to get 'emotional' about this they may become
unwilling to accept this has happened once the fuse has been lit. :-)


The thing is, does this really matter? As well as context, we have the
circumstances to consider: This is an open forum attended *voluntarily* by a
cross-section of different people with varying communication skills,
restricted to the written word only - no handwaving, face-pulling &c. and no
pix or diagrams unles they post a bit of Show n Tell. AFAIAC, there is some
duty of understanding on the part of the 'communicatee(s)' and it's up to
them to get clarification on any point that may have been poorly made.

If things get a little heated from time to time it's not a big problem in my
book - that's mainly because it is possible to post into this sort of forum
with a high degree of impunity and I have to admit it can spice things up a
bit from time to time. (Turgid exchanges of factual accuracy in clipped,
precise, *correct* terms may be helpful and informative but they aren't
always very entertaining!! ;-)



Hence my reaction to pop up a 'warning flag' that this can occur. I'd
agree
though that my wish for more 'precise' language can, itself, get in the
way
of some discussions. With 'fuzzy' real languages like English you can't
always get clarity without some fuss first...

I may be more sensitive than usual to this as I am currently reading the
'answers' perhaps sic in exam papers. Noting how some people seem to
misunderstand what most have found perfectly clear!


That's the nature of human beans. I don't like 'examinations' per se - I
think it's as good a way of weeding out possible future genius as you can
get! I wouldn't be surprised if the guy who was destined to find a cure for
the common cold/cancer (or both) wasn't stopped in his tracks by the
'examination system'!! (Think Winston Churchill here....)



I suppose that the reality is that whatever words or explanations you use,
the diversity of human minds, and the fuzzness of language, means that
some
will not understand what was actually meant. All you can do then is to try
alternative approaches until sufficient pennies have dropped. :-)


Indeed - consider your drift well and truly caught!! ;-)

Digital volume control question....
 

Serge Auckland wrote:

Andy Evans wrote:
As to audio quality, a conductive plastic pot will have zero effect on
audio quality.

Here's another view from Allen Wright (designs amps)
"Vishay cermet are good. One of the biggest con acts has been the
pushing of conductive plastic pots to the audio industry. I don't care
what the brand is - if they make a CP and a cermet (or even a quality
carbon) then my experience is that the cermet KILLS the CP for sonic
quality. The VISHAY cerment (made by their french wing Sfernice))
sounds. like two good fixed resistors, the identical looking CP sounds
like ****! Allen

Oh dear someone else who thinks resistors have a sound.

A pot, whether cermet, conductive plastic, carbon or whatever is a pure
resistance (discounting irrelevant tiny amounts of capacitance and
inductance- wirewound pots excepted) and consequently are linear to the
limits of measurement. Therefore how any pot can be better than another
for sonic qualities is beyond me. Pots vary in the accuracy of their
law, the noise made when being altered, tracking on stereo, how long
they last before track wear is evident etc. Sonic differences are just
not there.

The funny thing about this is that the referenced Mr Wright says he likes Vishay
Sfernice's cermet pot, yet Vishay Sfernice themselves promote the conductive
plastic version as better for audio. Nothing to do with 'having a sound' btw -
it's simply that cp pots have lower rotational noise ( they don't crackle when
turned ).

You might care to know that famous high-end UK recording console maker Neve uses
those very same cp pots that Mr Wright rejects.

Graham

Digital volume control question....
 

Eiron wrote:

Serge Auckland wrote:

I think the nub of your response is that people "believe" things sound
different. It's the same mental process that have people believing in
God, the Tooth Fairy and Santa Claus. They don't have a shred of
objective evidence that things sound different, just their faith.

I'll accept that pots, capacitors, resistors etc. sound different when I
see objective measurements that indicate that there should be a
difference and the results of properly conducted double-blind tests that
show that there was a difference.

So is it not the case that metal film resistors have lower noise than carbon ones,

The difference is less than it used to be. Carbon film has simply got better.

and that this gives an audible and measurable difference in phono and microphone
preamps?

With regard to noise it *can*. It's a question of whether in any given circuit the
excess noise of a resistor plays a significant part in the overall total noise. Often,
resistor excess noise may not be the big issue. Poor quality resistors can also have
excessive popcorn/flicker noise. That applies to poor quality metal film as much as it
does to carbon too.

* Excess noise is the part of a resistor's noise that isn't accounted for by ordinary
thermal noise.

Note that this is a question, not a statement. I haven't measured anything recently.

I have.

Graham

Digital volume control question....
 

Arny Krueger wrote:

"Serge Auckland" wrote in
message
Nick Gorham wrote:

http://members.aol.com/sbench102/caps.html

Interesting. I'll study it in the next day or two.

It's not what it seems. The testing procedures ignored the nonlinearity of
an audio transformer, and did not use the caps as they are typically used in
audio gear.

Very, very true. A ridiculous way to make such a test.

I can find *no* difference whatever between the various plastic film dielectrics
in a real world application whatever using Audio Precision test gear.

The business about ceramics is very old news and it seems he didn't test the
perfectly linear low-K types ( not available as 0.1 uF )

Furthermore, there's a very neat trick to avoiding any trouble with aluminium
electrlytics as coupling caps too ( as practiced by good pro-audio manufacturers
).

Graham

Digital volume control question....
 

Serge Auckland wrote:

I have never measured any increase in THD with a capacitor in circuit in
the amplifiers I have designed. This is true of all sorts of cap,
electrolytic, tantalum, polyester, polystyrene.

I've only seen it with small value electrolytics as coupling caps at low
frequencies and very high signal levels with low load impedance on the load end
of the cap ( *where the voltage across the cap starts to become significant* ).
Even so, the numbers are quite low. Roughly from memory with 10uF and a signal of
10V rms @ 20Hz into a 600 ohm load it was somewhere around 0.03%. Reduce the
signal level to something more typical, increase the load R, increase the
frequency and most of all using a larger cap ( to a more sensible 100uF ) all
reduce the figure. In fact with 100uF I simply couldn't measure *anything* except
with very high signal levels @ 20 Hz and even then it was barely out of the test
set noise floor.

In more typical real world use even the electrolytics produce no measurable THD (
AP THD floor is 0.0008% or -102 dB )

Graham

Digital volume control question....
 

Nick Gorham wrote:

Jim Lesurf wrote:

I can't recall ever building or using an audio amplifier or tuner that had
anything like this large an *audio voltage* across any of the *capacitors*.
Note the above is 70v RMS *between the capacitor terminals*. i.e. not just
an input where most of the voltage appears elsewhere. I have certainly
built (and use!) amps which have audio voltages this large inside them, but
not between the terminals of any of the signal capacitors.

The fact you may not have built such a thing, doesn't mean they do not
exist. Using a coupling cap between a driver and the grid of a 211 would
have this sort of voltage, as will most driver valves. a 845 would have
a much higher voltage.

Utter rubbish. I suggest you measure *across* it.

Graham

Digital volume control question....
 

"Keith G" wrote in message

"Arny Krueger" wrote in message
...
"Rob" wrote in message

Arny Krueger wrote:


Some of the rest of us are mostly interested in
veridical perceptions. Illusions are fun, but that's
about it for them.

'Veridical perception' - oxymoron.

Wrong.

Google finds upwards of 100,000 references to this
phrase.

Wrong.

different.

15,300 actually.....

The myth here is that Google results are unchanging.

The current number is "about 14,300". YMMV.

However, 10,000 or 100,000 aren't signfiicantly different in this context.
It's all "lots".

BTW thanks for distracting the discussion on a trivial point - that's known
as the proverbial "red herring" argument. I knew you couldn't do any better
than that - like try to stay relevant.

Digital volume control question....
 

Arny Krueger wrote:
"Keith G" wrote in message

"Arny Krueger" wrote in message
...
"Rob" wrote in message

Arny Krueger wrote:

Some of the rest of us are mostly interested in
veridical perceptions. Illusions are fun, but that's
about it for them.
'Veridical perception' - oxymoron.
Wrong.

Google finds upwards of 100,000 references to this
phrase.

Wrong.

different.

15,300 actually.....

The myth here is that Google results are unchanging.

The current number is "about 14,300". YMMV.

However, 10,000 or 100,000 aren't signfiicantly different in this context.
It's all "lots".

BTW thanks for distracting the discussion on a trivial point - that's known
as the proverbial "red herring" argument. I knew you couldn't do any better
than that - like try to stay relevant.



I think you were trying to point out to us all that your preferred
rationale was near-ubiquitous. My point that a google search showed that
1) it's relatively minor, and 2) context is important (IOW many of those
references could be critical).

So I at least was trying to get to the bottom of the basis of your
argument, rather than the outputs you generate.

Rob

Digital volume control question....
 

"Rob" wrote in message
...
Arny Krueger wrote:
"Keith G" wrote in message

"Arny Krueger" wrote in message
...
"Rob" wrote in message

Arny Krueger wrote:

Some of the rest of us are mostly interested in
veridical perceptions. Illusions are fun, but that's
about it for them.
'Veridical perception' - oxymoron.
Wrong.

Google finds upwards of 100,000 references to this
phrase.

Wrong.

different.

15,300 actually.....

The myth here is that Google results are unchanging.

The current number is "about 14,300". YMMV.

However, 10,000 or 100,000 aren't signfiicantly different in this
context. It's all "lots".

BTW thanks for distracting the discussion on a trivial point - that's
known as the proverbial "red herring" argument. I knew you couldn't do
any better than that - like try to stay relevant.

I think you were trying to point out to us all that your preferred
rationale was near-ubiquitous. My point that a google search showed that
1) it's relatively minor, and 2) context is important (IOW many of those
references could be critical).

So I at least was trying to get to the bottom of the basis of your
argument, rather than the outputs you generate.



Take no notice of Arny, Rob - he's just whining because he got pulled up for
posting a wildly inaccurate 'factoid'...!!*

Ya gotta larf tho' - he introduces the point into the thread and then tries
to batter me with *irrelevancy* charges! (Besides which, I already tole him
it's my thread and I'll take where I want!!)

Like this f'rinstance: Go scrute my new/latest 'Faure' horns:

http://www.apah69.dsl.pipex.com/show/faure.JPG

http://www.apah69.dsl.pipex.com/show/faure2.JPG

The drivers are just out the box and fitted only an hour or so ago and they
*already* sound very **beguiling**!! (Takes weeks to get 'em browned in
properly, but they are amazing right from the off!!) My first 'custom'
design (OK, *tweaked* Fostex standard design....)

Gotta say it - these Visaton drivers are an absolute doddle and a fraction
of the price of the equivalent Fostex units. Get them from Neil at Impact
Audio:

http://www.impactaudio.co.uk/

Top bloke, top service and although his main business is 'industrial' he's
an audio enthusiast and very interested in the 'firewood horn' phenomenon!!

What about the little placky grilles - do they look OK?


* (So, what's new? :-)

Digital volume control question....
 

On Thu, 1 Jun 2006 16:21:35 +0100, "Keith G"
wrote:

Like this f'rinstance: Go scrute my new/latest 'Faure' horns:

http://www.apah69.dsl.pipex.com/show/faure.JPG

http://www.apah69.dsl.pipex.com/show/faure2.JPG

The drivers are just out the box and fitted only an hour or so ago and they
*already* sound very **beguiling**!! (Takes weeks to get 'em browned in
properly, but they are amazing right from the off!!) My first 'custom'
design (OK, *tweaked* Fostex standard design....)

Your carpentry is definitely improving - but the cable entry? Do tell!

d

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