On 7/30/2014 5:00 PM, Lostgallifreyan wrote:
Jerry Stuckle wrote in news:lras98$ebf$1@dont-
email.me:

As for determining whether it is oscillating or not - I wouldn't trust
anything short of a good spectrum analyzer. The signal could be
anywhere (and changing frequency). A spectrum analyzer will still show
it; a receiver won't necessarily.


No clues at all? I remember when I first set up that little MAR-6 based
preamp, it had some nasty side effects on the sound till I added a springy
ciopper alloy strip to each side on the underside of the board so it bit
gently into the aluminium case when I slid it in to it, finally curing the
local RF oscillations it had before I solved this. I was wondering if similar
audible sounds might be heard as a guide to other, larger scales of local
feedback and oscillation.


Not necessarily. Even if there were physical vibrations, they may be
out of the audible range. But even vibrations are not common. You were
lucky you could hear it.

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Jerry, AI0K

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