[RFI] Computer Speaker RFI
jim at audiosystemsgroup.com
Sun Mar 1 10:16:47 PST 2009
On Sun, 1 Mar 2009 10:19:09 -0500, k2qmf at juno.com wrote:
>Can anyone recommend or suggest
>a good cure for RF getting into
>computer external speakers??
Turn them off. :)
But seriously -- I assume you're talking about speakers with
built-in power amplifiers, either battery-operated or AC powered.
The electronics built into powered loudspeakers are notoriously
bad for RFI. It's a combination of bad/non-existent shielding,
bad/non-extistent filtering on input wiring, and pin 1 problems.
Pin 1 problems can be fixed with a suitable toroid choke, and a
filter can be added. BUT -- after you've done all that, you're
stuck with the shielding problem, which is NOT practical to fix,
and which is usually dominant.
I work in pro audio, and often have my ham talkie with me when I
tour the exhibit floor at trade shows. I routinely use the talkie
to probe each active loudspeaker I see that's hooked up and
running. So far, I've found ONE product that's immune to RFI. It's
made in EU by Genelec, and it costs about $3K.
For more detailed advice, see
There's at least one model of computer speaker advertised in QST
that claims to be RFI immune. I haven't tested it.
Jim Brown K9YC
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