Electronic – “Ideal” way of using 3-conductor cable for unbalanced audio

audiocablesunbalanced

I am intending to make some short (<30cm) unbalanced audio cables to interconnect devices on a musical instrument pedal board.

As a matter of convenience, I was thinking of using some Belden 9451 three-conductor cable for this because I have a lot of it. It has an insulated twisted pair (red & black) inside a shield wrap. (I wouldn't call it a braid)

Probably overthinking this, but I'm curious if there is a "best practice" for using three-conductor cable for an unbalanced audio signal – some immediate options being;

1 – twist both inner conductors together for signal, use shield for ground

2 – use one inner (red) for signal, twist black and shield together for ground

3 – use inner twisted pair exclusively..red for signal, black for ground…shield unconnected

or is it all the same when it comes to such short cable lengths?

Best Answer

That's not really three conductor cable, it's shielded two-conductor cable.

I'd use the twisted pair for signal and ground, and connect the shield to ground at one end only. That way it helps to shield your signal pair from noise but doesn't create a ground loop.