"RST Engineering" wrote in message
...
I wrote about such a design in Kitplanes within the last three years or
so.
If you are really interested, I can dig down into the archives and see
what
month and year.

Basically, you bias the mic on and use the volt or so of audio through a
capacitor to run the earphones. If you can hear yourself talk, the
headset
is working. No amplifier or intercom required.

Jim

Hey, I might be interested in that, for another project.
--
Jim in NC