Tom Corker wrote:
I'm trying to get a 500R impedance dynamic mic working with an old
IC-730. The rig does not have a built in preamp so you have to have
one in the mic casing.
I've found a suitable design by G3SEK (http://www.ifwtech.co.uk/g3sek/
in-prac/best-of.htm#icom) but it seems to be designed for Heil HC4 or
HC5 inserts. These seem to be 1000 ohm impedance. Am I going to cause
problems by using a 500 ohm mic with a preamp designed for 1000 ohms?
Can the deisgn of the preamp be modified for 500?

Cheers
Tom 2E0WNT



The 1,000 ohm input impedance shouldn't cause any problems at all;
many microphone preamplifiers have input Zs higher than the nominal
figure for the microphones with which they're used.

With all good wishes,

Kevin, WB4AIO.