From PPilgrim@teleglobe.ca Wed Dec  7 09:09:09 1994
Date: 7 DEC 94 09:14:32 EST
From: PPilgrim@teleglobe.ca
To: analogue@magnus.acs.ohio-state.edu
Subject: Re: radio interference


A solution to cut Rf entering your amp,mixer..etc is to shunt a 470nF
capacitor between the +signal lead and the signal ground/shield of
your cable. (you can do it inside your mixer between +signal in and
ground for each input but this is more work and a little trickier to 
do)

The capacitor acts as a High Pass filter which shunts the Radio frequencies
to ground with out effecting the signal. The lower audio frequencies are not 
shunted.
The easiest place to install the capacitor is within a 1/4" plug at one end
of the cable. The capacitors are available at most electronic shops/radio 
shacks etc. Values between 100-600nF work well.

A more expensive but similiar approach is a device by TDK which
clamps to the cable. I'm not sure if it's capacitive or inductive.

Btw if you reposition your synth and cables sometimes you can null
the interference because they act as antennas.

Philip Pilgrim