[chbot] Measuring capacitance of audio cables

[Trevor Wignall]

The electrical resistance of the different conductors is another relevant
parameter, not so much for the frequency response and linearity but more
for noise pickup. The quality of any shielding is also relevant....

On Tue, Sep 8, 2020 at 10:41 PM Helmut Walle <helmut.walle at gmail.com> wrote:

> Would a meta-study count as scientific work, too? That would get him
> around the need to take
> measurements himself, and the outcomes could potentially be more
> comprehensive and practically
> meaningful than measuring a necessarily very limited number of samples...
> just an idea.
>
> And a general note regarding all electrical cables: the metal - mostly
> copper - is usually the
> costly material in comparison to the plastic insulation materials. So the
> manufacturer can save
> money simply by using less metal. That makes the cable not only cheaper
> but also lighter and
> therefore less costly to ship, saving cost again... But obviously using
> less metal drives up the
> cable's impedance, and high cable impedance is undesirable for most
> applications. Based on this
> alone, you would expect better cables to cost more.
>
> Furthermore, as an alternative to measuring capacitance and / or
> impedance, these values can
> also be calculated if the profile of the cable and materials are known. It
> isn't all that hard
> to cut an audio cable cleanly to take a look through a microscope to
> measure cross-sections or
> diameters. Assume the wires to be copper (even if they have a bit of
> silver plating or similar),
> and make some educated guesses about the plastic insulation material used.
> It would also just be
> interesting to see how much copper you get per $ spent - if the market
> economy works as it
> should you would expect to pay a certain base price per meter, plus a
> certain increment per
> additional quantity of copper. (If something costs much more than you
> would expect based on
> this, let's call it brand hype, unless they can justify the higher price
> due to their machined
> gold-plated connectors.)
>
> All the best for the project!
>
> Helmut.
>
> On 08/09/2020 09:38, Paul Willmott-Dalton wrote:
> > Hello all
> >
> > I am trying to support my 14yo boy with his homework but am a bit out of
> my depth. He is aiming
> > to demonstrate understanding of the scientific method. To do this he
> wants to make a comparison
> > of the electrical properties of different brands of audio cables. His
> hypothesis is that there
> > is no difference between 'audiophile' cables vs cheapies.
> >
> > I under that folks talk about capacitance being a variable. I'm told
> that this will be very
> > small in any cable and potentially difficult to read (in the tens of pF
> range).
> >
> > Does anyone out there have the equipment necessary to do this? If so,
> could we bring some cables
> > to you for testing?
> >
> > Kind regards
> > Paul Willmott Dalton
> >
>
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