[Eeyore]

Ron Hardin wrote:

I'm completely unfamiliar with what optical cable is up to.

I'd like to electrically isolate a radio setup on one power main
circuit, from a mixer board and computer on the opposite phase power
main circuit. At the moment they're connected with 30 feet of regular
audio cable and an isolation transformer.

But the isolation transformer is no match for a lightning strike, and
I thought optical cable would be, given that there would be about 30
feet of it. It would save be disconnecting it every time a lightning
storm comes over.

What do I need, to use optical cable to replace what at the moment
terminates in conventional 3.5mm stereo jacks at each end?

Or do I have to start with completely different equipment and meantime
forget it.

Optical cables aren't designed to pass analogue audio so yes you need to
consider another strategy.

Graham