"Arny Krueger" wrote in message
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"Jo" wrote in
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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.

I keep hearing about this, but have never seen the problem up front and
personal. I have had RF problems but they were in the front end, not the
back end.

A while back I had an amp
that would pick up VHF taxi and police transmissions
quite clearly.

Brand - model?

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.

Most power amps already have chokes in series with their output terminals.


Arny
Ask any licensed radio amateur ( at least any one that got his license
before they started giving them away in cornflake packets ) about RF pickup
on speaker leads. It's a well known problem ...

See for instance

http://www.antennex.com/shack/Dec99/beads.htm

look towards the bottom under the heading " Stereo "

Arfa