Matthew

the problem arises due to the electronics of your speakers being built
to a price.

The signal which you are hearing is being captured by your speaker wires
which are acting as the aerial, being conducted into the audio amplifier
probably across the base/emitter junction of the output transisor(s).
It is then fed back through an RC network to the base and amplified.

This usually happens in poorer quality audio systems whose output stage
is driven too hard rather than in class A A/B B1.

The solution can take two forms.

1.   stop the RF getting in in the first place.
2.  altering the circuit.

The latter is of course more difficult so I suggest the former.

As you mention in your mail, use of ferrite rings is the usual first
step.

Radio Shack and Maplin Electronics both sell 2 inch diameter ferrite
rings.
If you position one of these almost to the unit, and then wrap a number
of turns round the ring this may well do the trick.
If not, their is a more complicated way which I will willingly describe
if need be.

David


In message <[log in to unmask]>, Matthew Bullis
<[log in to unmask]> writes
>Hello, it's extremely annoying that I can hear a local radio station at low
>volume when I use my computer speakers. The speakers are the amplified kind
>with a subwoofer, and so they must be plugged in to operate. I've got them
>plugged into a power strip, but switching them to another outlet without the
>power strip doesn't solve the problem that I can hear the radio station at a
>low, but annoyingly noticeable volume. It makes it hard to concentrate,
>especially when I'm doing audio editing. Is there something I can do to fix
>this, either by changing something, or buying a filter? This has nothing to
>do with the computer, as just having the speakers on will produce the radio
>station. I asked on another list, but figured that with a lot of electrical
>knowledge on this list from working with amateur radios, that someone might
>have a suggestion? Someone already mentioned faerite cores and beads. What
>do you think?
>Thanks a lot.
>Matthew
>
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>Thanks a lot.
>Matthew
>
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--
David W Wood