[Elecraft] Dave Clark Microphone

[Ken Rice]

As others have mentioned,  the M-7A electret's output will be too high
for good performance on the K2 (400mV RMS ±6dB into 150 ohm load @
1kHz for 114dB SPL input), so you'll need to pad it down.  And you'll
need a series 1uF capacitor (again, as others have mentioned).

Jim, W6JVE, uses an aviation headset on the K2 with the Radio Shack
1000:8 ohm transformer:

     http://www.ac6rm.net/mailarchive/html/elecraft-list/2003-02/msg00306.html

If you don't care about keeping the Clark headset in stock form, you
can replace the M-7A element with the three-dollar Radio Shack
electret element that will work with the DC voltage and expected mic
output level at the K2's mic jack.

     http://www.ac6rm.net/mailarchive/html/elecraft-list/2004-01/msg00197.html

Please let us know how it works out.