Randall Merrill wrote:
Eric,
Thanks for the suggestion. I'll get a chance to test it tomorrow.
I'm just curious, why 82pF?
Thanks,
Randy

Well, everyone will have a different opinion, but I would have started
at 1000 pF (Radio Shack #272-126), tRC is still a couple orders of
magnitude away from audio. Why not yank it down?

If you want to go with the "82 pF" suggestion, Radio Shack 100 pF is
#272-123.

I would have said throw in a couple of ferrite beads in series before
the caps as well. Maybe 1K Ohm @100 MHz, DCR single digit Ohms, but I
don't see any at Radio Shack website. I'm used to my selection of
surface mount components. Someone else in here suggest a radial/axial
component. Or a common mode choke.

While I've got the Radio Shack site up on the browser, the snap-together
ferrite choke is #273-105. Get a couple. Cable end nearest preamp is
most important place.

Always, always walk into a Radio Shack with catalog number ready to
recite. Radio Shack sales people are clueless, but can look up a number
on the computer and b-line to the merchandise extremely quickly without
wasting your time, and you pre-empt any useless discussion by doing so.

Someone mentioned Shure. I see their A15RF, but it is only rated to 70
MHz and "$41.67". I suppose you could try it and return if it didn't
work. Obviously has a common mode filter in it, from the graphs.

All this assumes it comes down to "it's RF" and "the mic/cable" is the
pickup and you've done all the grounding things people suggested.