/I have built several headsets but have one with a microphone failure.
/I want to replace the microphone unit with a regular noise-cancelling
/microphone but presumably I need an amplifier as the output of the
/electret will not provide sufficient voltage swing to drive the first
/stage of the transmitter. Can you recommend a suitable circuit -
/preferably operating from the aircraft transciever microphone input ?
The last time I dug into one of those things, the amplifier was
a two transistor affair coupled with a handfull of jelly-bean
parts. That was on a Plantronics headset I owned about ten
years ago. I would hope that more modern headsets use some sort
of integrated circuit. As I recall, the Plantronics instruction
manual included a schematic of their electret amplifier. You might
also see if avioinics shops have service information on the various
microphones used in airplanes. I'll see if any of my friends
in the business have access to similar data.
Bob . . .
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