Msg: 2754 *Conference*

06-16-92 02:53:03

From: DAVID FIRTH

To : DREW BLANCHAR

Subj: REPLY TO MSG #2731 (ACOUSTIC COUPLER)

Thanks. I forgot that M100 owners are well versed in some computer techniques
that my PC-only buddies consider to be a lost art (especially those who grew up
in the cheap RAM, big disk era). No offense intended, of course. I now have the
pin-out and the circuit diagram from the Inside the M100 book. The circuit
shows the mic taking power from the M100 via a resistor in the coupler. The
author was less specific about the amplifier. He shows op amps, but doesn't
specify type. I plan to use a low power audio amp chip (LM386) in the first
rendition of the design. I plan to determine the necessary gain by tweaking the
circuit while viewing the output on an o'scope.