Peter, Bias is "added" to the tip via menu. The voltage you read on the 1st ring is the pull-up for the PTT & UP/Down buttons.
See the schematic for the MH3 microphone ( http://www.elecraft.com/manual/MH3%20Rev%20A.pdf ). It does show the connections to the mic plug. I can not find the Mic jack on the KX3 schematics. I used the MH3 schematic to make an adapter to interface my K3 microphones in case I need my KX3 to back-up my K3 & KPA500. 73 George AI4VZ -----Original Message----- From: Peter Eijlander (PA0PJE) Hi Dom, When I measure the mic connection with a standard 3.5 mm. stereo cable with two RCA plugs at the other end, I end up having no voltage on the tip of the 3.5 mm plug and 2.4 volts on the middle ring. That is the situation I'd expect it to be: These mics are usually wired for mic inputs of soundcards and they carry the bias supply voltage on the middle ring and the AF output comes from the tip. . . . ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
