In ,
Arny Krueger typed:

The most likely way that RF enters power amps is thorugh the input
terminals. Most of the time there is a simple small series resistor
and parallel cap at the input that deals with this issue.


RF can also enter via the speaker leads if this isn't taken care of in the
design. A while back I had an amp that would pick up VHF taxi and police
transmissions quite clearly. It even picked up Radio Moscow on occasions
when global MF radio propagation conditions were favourable. Home made
longitudinal chokes on the speaker leads fixed most of this problem.

Jo