"Paul G." wrote

I had considerable trouble with a cable feed causing hum and bizarre
behaviour with a Linn CD player and power amp.

You have a cable feed to a CD player?

I am not aware of any common commercial RF isolator for this
purpose. Maybe its an opportunity for someone to market it as a cure
for some of the weird effects you get when tied into cable.


So called "Braid-breakers" have existed for many years to help keep out
interference picked up on the braid of a TV or FM radio downlead. They work
in a similar way to what you have described, ie. a small ferrite-cored
transformer.

David.