Fellow Topbanders,
I've run into a glitch! The local switchers have found a
new way to harass me! :-)
I am looking for suggestions on *aggressive* power supply
decoupling / filtering for my W7IUV preamp. The preamp
works great when powered from a battery but is totally
useless on the power supply I built for it. Experiments
thus far have not led to an acceptable solution.
The preamp is the latest revision W7IUV circuit from Larry's
web site, using a 2N5109. It is very well shielded. The
power supply consists of transformer, full wave bridge,
LM317T regulator plus output filtering (the filtering is
what I am now experimenting with). Incidentally, I used a
Corcom EMI filtered power entry module for the AC line to
the power supply.
By all available evidence, the preamp is being killed by
noise from local switching power supplies (and/or other
crap!) entering via its power source. Again, all is well
if I power the preamp from a battery.
Thanks & 73,
Paul N1BUG
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