"Eeyore" wrote in
message
Jim Lesurf wrote:

So far as I can recall, it isn't 'news' that caps can
have mechanical resonances. The claim that is
interesting is that they are audible. But to decide, I'd
need to know a lot more about how the 'results' were
obtained. For reasons like those others have already
mentioned.

Crappy quality ones (electrolytics at least) can be bad.
I've come across some. Doesn't mean you have to use magic
dust or incantations to fix it though, just buy well-made
quality product.

One of the problems with NP electrolytics used in crossovers is that they
are often not exactly high-tolerance devices (+80, -20% is not uncommon),
and they are not high-stability or long-life devices, either.

Anybody who replaces parts that have fallen to say 10% of name-plate
capacitance, and finds an audible difference is not necessarily having an
imaginary experience, to say the least. I think this happens a lot.

Fortunately from the standpoint of good results, but unfortunately from the
standpoint of technical understanding, the replacement part is often some
kind of high end device that has been advertised to have magical properties.
Attributing the change to some magic dielectric or foil or esoteric means of
construction is of course foolishment. What really happened is that
something that was broken is now repaired, simple as that.

Arny Krueger wrote:

"Nick Gorham" wrote in message



I just tried the experiment on a few caps I have to hand.
The ones that produces a sound when driven by a sig gen
were a BC 368WKT 220nf, Acotronics MKP 47nf and a 2.2uf
ClarityCap SA. Ones that I tried that didn't prduce any
sound I could hear were from Solen and Mundorf.


Two problems:

(1) The stated problem seems to be not that the capacitor produces sound
(it's someplace inside the bowels of the enclosure) but that operating in a
sound field causes the capacitor's operation to be modulated by the sound
field.

Well, I think not, in the video, the eng describes how they tried to
measure the capacitors sensitivity to external sound, and they found
nothing. Their point was that internal resonances were taking place, and
as a SIDE EFFECT of this sound could at times be found to radiate from
the cap.

(2) If you're going to test capacitors, it would seem that you would want to
test them as they are used. IOW with the kinds of voltages, currents and
sound fields that one sees in a loudspeaker.


Yes, agreed, and I believe this is what ICW did, I was not trying to
test anything other than the assertion that caps would not produce any
sound. I assume the logic was that the paper claimed that the caps
resonate, and also produce sound, so by stating that they do not
actually produce sound the assumption seems to be that the posibility
that resonance takes place is removed.

Hopefully Jim will manage to find more details.


Note that the output stages of some SS amps produce audible sounds related
to the signals that they are amplifying.


Hmm, and a single cap might be a load that would cause some amps problems.

--
Nick

Arny Krueger wrote:

"Nick Gorham" wrote in message


Don Pearce wrote:


But which effect is being heard in the blind test? I
note he didn't claim double blind.

What does ITU-R BS.1116-1 specify?


Double blind.

"To conduct subjective assessments in the case of systems generating small
impairments, it is necessary to select an appropriate method. The
"double-blind triple-stimulus with hidden reference" method has been found
to be especially sensitive, stable and to permit accurate detection of small
impairments. Therefore, it should be used for this kind of test."



Thanks for that info Arni.

--
Nick

"Nick Gorham" wrote in message

Arny Krueger wrote:

"Nick Gorham" wrote in message



I just tried the experiment on a few caps I have to
hand. The ones that produces a sound when driven by a
sig gen were a BC 368WKT 220nf, Acotronics MKP 47nf and
a 2.2uf ClarityCap SA. Ones that I tried that didn't
prduce any sound I could hear were from Solen and
Mundorf.


Two problems:

(1) The stated problem seems to be not that the
capacitor produces sound (it's someplace inside the
bowels of the enclosure) but that operating in a sound
field causes the capacitor's operation to be modulated
by the sound field.

Well, I think not, in the video, the eng describes how
they tried to measure the capacitors sensitivity to
external sound, and they found nothing.

Thanks. I sincerily tried to listen to the video, but the screaming and
clanging from my BS meter was waking up the whole neighborhood prematurely,
so I had to stop before the police showed up. ;-)

Their point was
that internal resonances were taking place, and as a SIDE
EFFECT of this sound could at times be found to radiate
from the cap.

Which leaves me wondering where the beef is.

It seems to me that that the evidence you say they uncovered: "they tried to
measure the capacitors sensitivity to
external sound, and they found nothing" should have led them to conclude
that they were on a fool's errand.

However, the fool's money has been screaming in their ears, filling heir
coffers, feeding their children, and thus motivating them onward to higher
and higher levels of foolish behavior for at least 10 years, so being
well-conditioned to act foolishly, they bravely soldiered on.

Arny Krueger wrote:

Which leaves me wondering where the beef is.

It seems to me that that the evidence you say they uncovered: "they tried to
measure the capacitors sensitivity to
external sound, and they found nothing" should have led them to conclude
that they were on a fool's errand.

However, the fool's money has been screaming in their ears, filling heir
coffers, feeding their children, and thus motivating them onward to higher
and higher levels of foolish behavior for at least 10 years, so being
well-conditioned to act foolishly, they bravely soldiered on.



Maybe so, The main reason I posted the link was in the hope that others
(esp Jim) would be interested enough to dig a bit deeper.

As a entirly differebt topic you may have some input on Arni, I have
been enjoying myself playing with/learning VHDL and using a FPGA between
a spdif reciever and some DAC's, just for the hell of it.

So I have been looking into the theory and practice of digital
filtering, as much as anything to find something to try and keep the old
gray cells going, writing data processing software for a living pays the
bills but gets a bit simple after 10 years.

Chord and several others before them are making big noises about their
new DAC's which claim wonders due to the use of a filter designed by
someone called Robert Watts, he calls it a Watts Transient Aligned
filter. Other than on Chords pages, or related adverts/review sites I
can find no mention of this alg on the web at all, and neither can I
find anything in the IEEE library. Does it ring a bell with yourself (or
anyone) or is it just more BS?

--
Nick

In article , Nick Gorham
wrote:
Jim Lesurf wrote:
In article , Nick Gorham


I just measured it, somewhere around 65R, off load it was giving 8v RMS.
I said with the cap in place, it was producing about 5v P/P on a scope
trace, or about 2v RMS.


If I understand the ClarityCap papers correctly, you'd need to find
the mechanical resonance of each cap to get a peak level of vibration.
So 5k might not give as large a response as some other frequency.


Yes, but I was just trying to test the assumption that no cap would
produce any noise, having found that some do under simple to achieve
conditions, there is scope to perform more detailed tests.

OK. However the above makes clear that this is only likely to be a problem
in uses like a loudspeaker crossover where the current and power transfer
levels are relatively high. Even there, you needed to put your ear near the
cap to hear the sound - with an input signal of the order of 1 Watt.

I wonder if something like a strain gauge attached to the cap would be
the best way to measure any vibration.

The problem is that any sensor near the cap may respond suriously to the
E-fields or H-fields. So may not simply sense the sound/vibration. However
it may be an advantage here that that would tend to be at the drive
frequency, not the doubled frequency of sounds created by the forces you'd
expect.

Slainte,

Jim

--
Change 'noise' to 'jcgl' if you wish to email me.
Electronics http://www.st-and.ac.uk/~www_pa/Scot...o/electron.htm
Armstrong Audio http://www.audiomisc.co.uk/Armstrong/armstrong.html
Audio Misc http://www.audiomisc.co.uk/index.html

In article , Nick Gorham
wrote:
Arny Krueger wrote:

"Nick Gorham" wrote in message



(1) The stated problem seems to be not that the capacitor produces
sound (it's someplace inside the bowels of the enclosure) but that
operating in a sound field causes the capacitor's operation to be
modulated by the sound field.

Well, I think not, in the video, the eng describes how they tried to
measure the capacitors sensitivity to external sound, and they found
nothing. Their point was that internal resonances were taking place, and
as a SIDE EFFECT of this sound could at times be found to radiate from
the cap.

That is my impression from the documents I've seen thus far. However they
lack any real detail, so it is hard to be sure at present.

IIUC the idea is that 'intermodulation distortion' of some kind will be
produced. The obvious snag is that the vibration seems mainly at a
resonance, so would be between anything at that specific frequency and
others. i.e. Not a general intermod effect, but one with a tuned response
for the nonlinearity.

But as yet, I am seeking/awaiting more info.



(2) If you're going to test capacitors, it would seem that you would
want to test them as they are used. IOW with the kinds of voltages,
currents and sound fields that one sees in a loudspeaker.


Yes, agreed, and I believe this is what ICW did, I was not trying to
test anything other than the assertion that caps would not produce any
sound. I assume the logic was that the paper claimed that the caps
resonate, and also produce sound, so by stating that they do not
actually produce sound the assumption seems to be that the posibility
that resonance takes place is removed.

Hopefully Jim will manage to find more details.

Again, IIUC the tests for 'audibility' used switchable caps in the same
network for the same speaker. if so, that does common-mode various other
factors. But I currently have no data on how close the cap specs were apart
from the claimed behaviour. Nor details of how the tests were done, or any
way to tell the statistical significance of the presented results.

So as yet, I'd say, "Interesting, but still awaiting relevant data to be
able to judge." :-)

Slainte,

Jim

--
Change 'noise' to 'jcgl' if you wish to email me.
Electronics http://www.st-and.ac.uk/~www_pa/Scot...o/electron.htm
Armstrong Audio http://www.audiomisc.co.uk/Armstrong/armstrong.html
Audio Misc http://www.audiomisc.co.uk/index.html

In article , Nick Gorham
wrote:


Chord and several others before them are making big noises about their
new DAC's which claim wonders due to the use of a filter designed by
someone called Robert Watts, he calls it a Watts Transient Aligned
filter. Other than on Chords pages, or related adverts/review sites I
can find no mention of this alg on the web at all, and neither can I
find anything in the IEEE library. Does it ring a bell with yourself (or
anyone) or is it just more BS?

To tag on, I'd also be interested in this. Can't recall offhand if it has
appeared in JAES. (However, I'll check when I get a chance.)

I can see the general idea, but can't recall seeing the details of the
'WTA' design. As Peter Craven has shown, you can do designs like this in
various ways.

Slainte,

Jim

--
Change 'noise' to 'jcgl' if you wish to email me.
Electronics http://www.st-and.ac.uk/~www_pa/Scot...o/electron.htm
Armstrong Audio http://www.audiomisc.co.uk/Armstrong/armstrong.html
Audio Misc http://www.audiomisc.co.uk/index.html

Nick Gorham wrote:
Arny Krueger wrote:

Which leaves me wondering where the beef is.

It seems to me that that the evidence you say they uncovered: "they
tried to measure the capacitors sensitivity to
external sound, and they found nothing" should have led them to
conclude that they were on a fool's errand.

However, the fool's money has been screaming in their ears, filling
heir coffers, feeding their children, and thus motivating them onward
to higher and higher levels of foolish behavior for at least 10 years,
so being well-conditioned to act foolishly, they bravely soldiered on.



Maybe so, The main reason I posted the link was in the hope that others
(esp Jim) would be interested enough to dig a bit deeper.

As a entirly differebt topic you may have some input on Arni, I have
been enjoying myself playing with/learning VHDL and using a FPGA between
a spdif reciever and some DAC's, just for the hell of it.

So I have been looking into the theory and practice of digital
filtering, as much as anything to find something to try and keep the old
gray cells going, writing data processing software for a living pays the
bills but gets a bit simple after 10 years.

Chord and several others before them are making big noises about their
new DAC's which claim wonders due to the use of a filter designed by
someone called Robert Watts, he calls it a Watts Transient Aligned
filter. Other than on Chords pages, or related adverts/review sites I
can find no mention of this alg on the web at all, and neither can I
find anything in the IEEE library. Does it ring a bell with yourself (or
anyone) or is it just more BS?


The blurb on the Chord site features the sentences "It is well known
that 96 kHz (DVD Audio) recordings sound better than 44.1 kHz (CD)
recordings. What is not well known is that 768 kHz recordings sound
better than 384 kHz and that the sound quality limit for sampling lies
in the MHz region".

With that piece of gibberish as a starting point, I think we are safe in
assuming that what follows won't be a great deal better.

d

In article ,
Nick Gorham wrote:

Chord and several others before them are making big noises about their
new DAC's which claim wonders due to the use of a filter designed by
someone called Robert Watts, he calls it a Watts Transient Aligned
filter. Other than on Chords pages, or related adverts/review sites I
can find no mention of this alg on the web at all, and neither can I
find anything in the IEEE library. Does it ring a bell with yourself (or
anyone) or is it just more BS?

There's an 2006 thread on the prosoundweb forum, but the discussion
diverges into dithering. Err, a discussion of dither.

http://recforums.prosoundweb.com/index.php/t/18922/0/

Stephen