[Elecraft] RF hardening a computer speaker.

[Robert McGwier]

HI!

Come to think of it, my old faithful stereo amplifier is almost
30 years old!  Okay, then take great care that your audio
amplifier is of a design that will work into a capacitive
load.  Mine will not.  I also replaced all leads going to
computer speakers with twisted pairs, I forgot about this.


Good luck!
Bob
N4HY


-----Original Message-----
From: elecraft-bounces at mailman.qth.net
[mailto:elecraft-bounces at mailman.qth.net]On Behalf Of Jim Brown
Sent: Friday, June 04, 2004 6:05 AM
To: Elecraft List
Subject: RE: [Elecraft] RF hardening a computer speaker.

>Many recommend a 0.01 uf across the speaker leads.  DO NOT DO THIS.  We
>are years beyond the old tube era and many solid state audio devices just
>hate working into capacitive loads.  If you have a 0.01 uF across the
>leads, get rid of it.  You can really blow a high power stereo easily
>with this capacitor trick.

Horse pucky. This hasn't been true for at least three decades. Any power
amplifier that won't work into a 0.01 uF load is a HUGE design mistake.

But DO replace any zip cord that you might be using as loudspeaker cable
with
twisted pair. Twisting is VERY helpful in reducing RF pickup on loudspeaker
wiring. Yeah, I know that many of the high futility speaker cables  are zip
cord, but the folks who sell them are MARKETING folks, not engineers.

But none of this is his problem -- they are amplified loudspeakers, probably
terribly shielded.

Jim Brown   K9YC
http://audiosystemsgroup.com


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