[rec.audio.high-end] Using surplus cable

mthome@BBN.COM (Mike Thome) (07/03/90)

  Over the years, I've manages to accumulate a few big boxes full of
surplus industrial-grade coaxial (and some triaxial & ribbon) cable,
with vague ideas of putting some of it to use in my audio system.
  My question to the general "you" is what should I watch out for in
constructing my own cables: since all this stuff is surplus/discarded/
etc , I have so specs or identification except what is printed on the
insulation.   For instance, I've heard that (thin) ethernet cable is a
bad choice for audio (but with no accompanying reasons).  Any benefit
to using triax (i.e. connect the innermost two conductors?  Ground the
outermost to different points?)
  I'm told that there is at least one company which sells high-end
speaker wires made from ribbon cable... is this true?  Would you want
to alternate conductors or group 'em?  How 'bout cables made up of a
bunch of twisted pair sets?

	thanks,
		-mik (mthome@bbn.com)

kjetil@ifi.uio.no (Holm-Kjetil Holmsen) (07/05/90)

mthome@BBN.COM (Mike Thome) wrote:
>
>For instance, I've heard that (thin) ethernet cable is a bad choice
>for audio (but with no accompanying reasons).  Any benefit to using
>triax (i.e. connect the innermost two conductors?  Ground the
>outermost to different points?)
>

The only reason I can think of why (thin) ethernet cable might be "bad" for
audio is that it might have the wrong impendace.  Coaxial antennae cable,
for example, has an impendace of 75 Ohms and is thought of as "not good".
But, by all means: Try it and post the results.

If you by "triax" mean a cable with a central conductor with two (isolated)
sheilds, there is at least one company that sells cables like that.  I have
a pair made by "Eagle Cables".  

I have mounted them in a "pseudo ballanced" configuration: Central conductor
to signal, innermost sheild to ground on _both_ ends and outermost sheild to
ground on _one_ end only.  When using the cable, connect the end where the
outermost sheild is mounted to the component with the lowest impendance
(usually the "sender" ??).

Other cable that might make good interconnect cables is "microphone" cable
or "guitar" cable.  That is: a cable with two isolated central conductors
and (usually) a common sheild.  These are usually mounted in a pseudo
ballanced configuration, as described above.

Happy cable "hacking", and keep us posted on the results.

Holm-Kjetil Holmsen, Comp. Sci. student		email: kjetil@ifi.uio.no
Institute for Informatics
University of Oslo
NORWAY