Re: Digital volume control question....

In article <447570bd$1_4@xxxxxxxxxxxxxxxxxxxxxxxxxxxxx>, Serge Auckland
<serge.auckland@xxxxxxxxxxxxx> wrote:
[snip]

As mentioned earlier, in my design days, I was never aware of any
increases in distortion that resulted from capacitors in circuit, even
using electrolytics and tantalums (tantala?) provided they were well
polarised.

My experience was similar. When I was designing amps for a day job, the
issue of 'electrolytic caps' and 'capacitor sound' became quite a trendy
one in the magazines, and with the gurus of the time.

I did some measurements which - in some cases/circumstances showed that
electrolytic caps could, indeed, produce measurable nonlinearities. However
I also found that:

1) provided that he caps were of good quality and had a fairly high
capacitance value, etc, then the level of nonlinearity was pretty small.
i.e. much the same results and conclusions which Doug Self published later
on when he did a more systematic examination of the topic.

2) That when I tested to see if anyone could tell the difference between
using an electrolytic cap from a 'fancy' non-electrolytic one as, say, an
input decoupling cap, no-one could if they only had the sounds to go on.
This required the caps to have the same value, chosen appropriately, but
once this was done, no-one I ever tried them on could tell 'talk from
splutter'. :-)

Having a preference for making up my own mind, based on evidence, I decided
to regard as dubious (or worthless) the claims made about this in magazine
reviews, etc...

Since that time, I've seen continued assertions and claims that people
*can* hear the differences. But not seen any reliable evidence that they
can, based only on sound, and when the caps are chosen and used in a
reasonably appropriate and relevant manner. I have seen various claims like
those on the pages Nick directed us to, though, but where the results seem
to of dubious relevance or reliability for reasons like those we have
discussed in this thread. There was a similar report by Martin Collums some
years ago, based on applying an excessively high ac current and terminal pd
to an electrolytic cap.

Thus I chose decent quality electrolytic caps in some places in the amps I
have designed, and use, and seem to have lost no sleep over this. The music
still sounds lovely to me. :-) I was listening to some Ravel performed by
Dutoit and the Montreal orchestra yesterday. Can't say I noticed the caps
getting in the way of the results sounding superbly natural and the
performance being exciting. I admit I changed the caps after 25 years of
use, but I am not sure I noticed any alteration as a result. :-)

However if someone *does* show they can tell one from another, by sound
alone, using caps and a situation which is relevant, then I'd love to know
about it. Although this does not mean a case where a cap is faulty or
obviously inappropriate for a reason which would be obvious for engineering
reasons. With any type of component, you can probably find some dreadfully
made examples...

Slainte,

Jim

--
Electronics http://www.st-and.ac.uk/~www_pa/Scots_Guide/intro/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
.

Relevant Pages

  • Re: Recommended capacitors for AF circuits
    ... I believe to from my choice of polarized electrolytic caps (220n ... and 470n) where polarized caps are not indicated (application circuit ... The electrolytics are the only ones I have at the moment, ... capacitors shown on the LM1036 app ...
    (sci.electronics.design)
  • Re: Recommended capacitors for AF circuits
    ... I'm playing around with a circuit, but I am getting a lot of squeal ... I believe to from my choice of polarized electrolytic caps (220n ... The electrolytics are the only ones I have at the moment, ... capacitors shown on the LM1036 app ...
    (sci.electronics.design)
  • Re: Recommended capacitors for AF circuits
    ... I'm playing around with a circuit, but I am getting a lot of squeal ... I believe to from my choice of polarized electrolytic caps (220n ... The electrolytics are the only ones I have at the moment, ... capacitors shown on the LM1036 app ...
    (sci.electronics.design)
  • Re: Highest energy cap thats available in hobby volumes .. maybe a few hundred pieces
    ... books specify that you should put equalizing resistors across ... Electrolytics and diodes are kinda like zeners- they'll self-klimit the ... and even if they did, its only at DC; suck a wallop of current out, and watch the voltage distribute itself according to capacitance ratios. ... This thump was big enough that the aforementioned cap value "balancing" occurred, over-voltaging the shit out of some caps, which failed spectacularly. ...
    (sci.electronics.design)
  • Re: Help with SMD Components
    ... There are 'electrolytic' caps on that board in a format different from the ... tantalums rather than traditional wet electrolytics. ... yellow "C114" at the bottom left of the second picture. ... intermittant, I have another ipod that the menut button doesn't work but is ...
    (sci.electronics.repair)