"Iain M Churches" wrote in message
...

"Trevor Wilson" wrote in message
...

"Iain M Churches" wrote in message
...
Happy New Year to All:-)

It would be interesting to know how many on this
group think/find that:

a) capacitor "upgrade" results in a clearly audible
improvement.

**It may, depending on a whole bunch of factors.

Yes indeed. Care to elaborate?

**Sure.
* What the cap is to be used for.
* What other characteristics of the cap happen to be relevant.
* The linearity of the rest of what is in the system.


The sales technician to whom I refer below tells me that
polytetrafluoroethylene (Teflon) capacitors are close to
perfect with sonic superiority, and have the lowest value
of "tan d" (I am sure Jim and Don will know what he is
talking about:-) This is also what Andy has discovered
in his own listening tests.

**PTFE caps are useful at HF, but little else, AFAIK. Regular, quality
dielectrics seem to be entirely adequate, IME.



b) a capacitor is a capacitor, and all caps of the same
value and voltage rating sound the same.

**Anyone who believes such a thing is a moron. Capacitors all have
various
losses and characteristics which may adversely affect sound quality, in
various parts of a circuit.

So quite a few morons on this NG then? :-))))

**It would seem so.


I posted a similar question to another (closed) group run by a
broadcasting
organisation. Of the twenty two who replied, seventeen had experienced
or thought they would experience a clearly audible change/improvement,
three were undecided, and two thought that their level of auditory
perception may not yet be high enough to hear what they expected to be
extremely subtle changes.

The reason for my question is that a local valve amp builder/component
salesman who uses Jensen caps, above all others has suggested that
we should build two identical µ-follower pre amps, one with
Jensen and the other with RS or Farnell standard components.


**Why bother? Just use direct coupling. Coupling caps are just dumb.


He says that the reason that Jensen seem to sound better is due to
their "dielectric absorption" factor. Music is made up of a series of
transients of pulses. If we apply such a pulse to a capacitor this is
equivalent to charging and discharging it, and that any voltage left
on the capacitor at the end of the pulse is distortion. He refers us
to Morgan Jones for further reading.

He is confident that a competent listening panel will pick and
prefer the amp with the Jensen caps, type for type.
If not, some interesting eating of hats will follow:-))

Mike G seems to have already done a similar test, with
Jensen silver foil caps in one channel of a power amplifier.
His group picked out the Jensen channel every time.
I am not suggesting that these audible differences only apply
to Jensen. There are many other makers whose products
may well fall into the same category. Interesting.

**Without knowing the details of the tests, I can't comment further. I
suggest that direct coupling makes far more sense, however.


--
Trevor Wilson
www.rageaudio.com.au

"Trevor Wilson" wrote in message
...

"Iain M Churches" wrote in message
...

Mike G seems to have already done a similar test, with
Jensen silver foil caps in one channel of a power amplifier.
His group picked out the Jensen channel every time.
I am not suggesting that these audible differences only apply
to Jensen. There are many other makers whose products
may well fall into the same category. Interesting.

**Without knowing the details of the tests, I can't comment further.
Mike described it clearly.

Others who have done something similar, report that they could
pick out upgrade capacitors, though of course we do not know
the conditions under which their tests were carried out.
Having done this type of thing before,the chap from Jensen
is very confident. That's why I am interested to hear for myself.

After discussion with Jim, I thought to try ABX. Perhaps for the sake of
clarity, this should be the subject of new thread, which I will start as
soon
as I have some more information.

I suggest that direct coupling makes far more sense, however.


Indeed, but impractical in many instances. We intend to use for the
test a 6SN7µ-follower pre-amp which has exceptional linearity.
It *must* have a coupling cap on the output, (or 200V DC will apppear
on the RCA connector) and the circuit will not work if one uses DC coupling
between A1 and G2. It is the substitution of these two capacitors that form
the nucleus of the test.


Iain

In article , Iain M Churches
wrote:

"Trevor Wilson" wrote in message
...


I suggest that direct coupling makes far more sense, however.


Indeed, but impractical in many instances. We intend to use for the
test a 6SN7µ-follower pre-amp which has exceptional linearity. It *must*
have a coupling cap on the output, (or 200V DC will apppear on the RCA
connector) and the circuit will not work if one uses DC coupling between
A1 and G2. It is the substitution of these two capacitors that form the
nucleus of the test.

One drawback of using this as the test is that you will be testing the
possible 'audibility' of different caps with the application of 200Vdc bias
being included. This may not give the same results as tests with nominally
0Vdc across the caps. Hence it becomes a test of the caps when large dc is
applied, not of other operating conditions. This has implications for
things like charge creep, stress, and charge storage effects in the cap
which do not arise in the same way with no d.c.

Secondly: Given that the 'tan delta' effects are nominally small, you will
have to take care not to 'swamp' them with other effects that vary when you
change cap. I've discussed this in detail elsewhere, I think, but the nub
of the problem is that something like tan delta for decent caps is similar
to either a tiny series resistance or a large shunt. This means the effect
of the 'environment' in which the cap is places may dominate this. For that
reason I have my doubts that it will be OK to use two 'different' valve
stages. (This assumes you are trying to test the hypothesis that tan delta
losses are the physical mechanism which gives rise to audible changes.)

Why not use a system that does not apply dc to the cap, and allows you to
ABX the cap in the same actual circuit?

Or is it part of the hypothesis that the audible cap differences may only
show up when significant dc levels are applied across the caps?

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

I took my dog out for a walk.
While it was ****ing on Iain M Churches's leg, he seemed distracted by:
Happy New Year to All:-)

It would be interesting to know how many on this
group think/find that:

a) capacitor "upgrade" results in a clearly audible
improvement.

b) a capacitor is a capacitor, and all caps of the same
value and voltage rating sound the same.


Iain

Bloody hell, been away for months (years?) and you're all still dancing the
same old tango. Try explaining conversations like this in the pub, at least
it'll clear a seat for you!

--
Despite appearances, it is still legal to put sugar on cornflakes.

"Triffid" wrote in message
...
Bloody hell, been away for months (years?) and you're all still dancing
the
same old tango. Try explaining conversations like this in the pub, at
least
it'll clear a seat for you!

But this is not a pub, it's an audio NG. There is (or should be) a
difference:-)
I asked a question, and received a huge number of replies on and off group.
I am grateful to all for there input. I note that you did not contribute:-)

We now plan to do some listening tests with a panel of ten people.
We shall no doubt all retire to the pub when the tests are complete.
The first round is on me:-)

Cordially,

Iain

I took my dog out for a walk.
While it was ****ing on Iain M Churches's leg, he seemed distracted by:
"Triffid" wrote in message
...
Bloody hell, been away for months (years?) and you're all still dancing
the
same old tango. Try explaining conversations like this in the pub, at
least
it'll clear a seat for you!

But this is not a pub, it's an audio NG. There is (or should be) a
difference:-)
I asked a question, and received a huge number of replies on and off
group. I am grateful to all for there input. I note that you did not
contribute:-)

snip

I have no view. Since I discovered that a) My HF limit is 13.5k and b) I'm
quite happy on MP3 @ 128, my interest in the topic has waned enormously. My
happiest listening is in the bath. My favourite music source is my Sky
receiver, the pictures are so much better.

Enjoy the beer, try not to sneer at the jukebox.

--
Despite appearances, it is still legal to put sugar on cornflakes.

In message , Triffid
writes
I took my dog out for a walk.
While it was ****ing on Iain M Churches's leg, he seemed distracted by:
"Triffid" wrote in message
...
Bloody hell, been away for months (years?) and you're all still dancing
the
same old tango. Try explaining conversations like this in the pub, at
least
it'll clear a seat for you!

But this is not a pub, it's an audio NG. There is (or should be) a
difference:-)
I asked a question, and received a huge number of replies on and off
group. I am grateful to all for there input. I note that you did not
contribute:-)

snip

I have no view. Since I discovered that a) My HF limit is 13.5k and b) I'm
quite happy on MP3 @ 128, my interest in the topic has waned enormously. My
happiest listening is in the bath. My favourite music source is my Sky
receiver, the pictures are so much better.

Enjoy the beer, try not to sneer at the jukebox.


My HF limit is even worse than that, at about 12kHz, which isn't
wonderful even for 52 years old, but I certainly wouldn't be happy with
128k MP3s! ATRAC Minidisc standard play, and 256k MP3 are OK, but even I
can still tell these from the CD (but only when listening via
headphones.)

It's not just the HF that low-bitrate MPs lose.
--
Chris Morriss

"Triffid" wrote in message
...
I took my dog out for a walk.
While it was ****ing on Iain M Churches's leg, he seemed distracted by:
"Triffid" wrote in message
...
Bloody hell, been away for months (years?) and you're all still dancing
the
same old tango. Try explaining conversations like this in the pub, at
least
it'll clear a seat for you!

But this is not a pub, it's an audio NG. There is (or should be) a
difference:-)
I asked a question, and received a huge number of replies on and off
group. I am grateful to all for there input. I note that you did not
contribute:-)

snip

I have no view. Since I discovered that a) My HF limit is 13.5k and b)
I'm
quite happy on MP3 @ 128, my interest in the topic has waned enormously.

Sorry to read that - sad news:-((
Don't worry about (to quote you) "your dog ****ing on IMC's leg".
That's not too serious. Trousers can be sent to the dry cleaners.
But do try to keep the dog away from your ear trumpet:-)

Iain

"Iain M Churches" wrote in message
...



I have no view. Since I discovered that a) My HF limit is 13.5k and b)
I'm
quite happy on MP3 @ 128, my interest in the topic has waned enormously.

Sorry to read that - sad news:-((
Don't worry about (to quote you) "your dog ****ing on IMC's leg".
That's not too serious. Trousers can be sent to the dry cleaners.
But do try to keep the dog away from your ear trumpet:-)

Iain





But do try to keep the dog away from your ear trumpet:-)

Nipper?? :-)