Richard

I used to use ex-military headsets and with a little experimentation I
designed an audio amplifier based on the BC108 transistor to do exactly
what RST are suggesting. There were a couple of capacitors and
resistors and a variable pot. The variable pot was the biggest item,
even though I used miniature versions. Unfortunately I am away from
home and I can't remember more, but maybe you have enough info now to
start your project. As I posted in a previous unrelated topic, low cost
replacement cables are available from Headsets Inc at $19
http://www.headsetsinc.com/price_list.htm . The transistor and
components will cost a few cents.

Stan


Richard Riley wrote:
On Sun, 1 Oct 2006 21:34:47 -0700, "RST Engineering"
wrote:

That's because it ain't $120 worth of jacks and wire. It is $120 worth of
amplifier that takes those few millivolts of microphone audio, uses the bias
voltage coming down the aircraft radio mic audio line, smooths that voltage
into a working voltage for an amplifier, and provides an amplifier that
takes those millivolts to volts to drive the aircraft radio.


But I can plug my ordinary David Clark headsets into the dull old Icom
(handheld) standard patch cable and they work fine. Is the
Comtronics mic totally different from the David Clark mic?