Author Topic: Electret mic and K3 and one way audio  (Read 1976 times)

Bob G3PJT

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Electret mic and K3 and one way audio
« on: 2014-12-10, 22:54:52 »
Hi
Been having a one way audio problem. My Icom SM20 works very well with my K3. But would not work with the RR Control unit set for the Elecraft hardware settings. After a lot of hunting we found that the mic did not produce any output when plugged into the Control. What seems to be happening is that although the mic is biased  the AF is filtered out.

Anybody seen the same effect ?

Thanks for any comments

73 Bob G3PJT

sm2o

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Re: Electret mic and K3 and one way audio
« Reply #1 on: 2014-12-11, 11:38:51 »
Hi

ICOM SM20 is not wired like most of the Icom mics, It need power for the mic element on a separate pin. The RRC power the mic on the mic wire "phantom feeding".

http://qrzcq.com/pub/RADIO_MANUALS/ICOM/ICOM--IC-SM-20-Microphone-schematics.pdf

73 de mike