[chbot] Measuring capacitance of audio cables
helmut.walle at gmail.com
Tue Sep 8 11:40:56 BST 2020
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
All the best for the project!
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
More information about the Chchrobotics