I am wanting to connect a computer headset to my K2. I bought the K2 used along with an Icom HM-12 hand mic that I have used successfully. I haven't opened the radio up to see what the bias resistor is inside of the K2, but I measure +5V between pin 1 and pins 7 and 8 of the microphone connector. I believe that means that a bias resistor has been connected internally to put the bias voltage that the HM-12 needs on pin 1. (As a sidenote, trying to measure the bias on pin 6 with my DMM appears to reboot the microprocessor, sending the LCD screen back to "ELECRAFT"!!)
I am not sure about the bias needs of the headset that I have, which I intend to use for infrequent SSB contesting. Following a recent message on this reflector, I measured the resistance from tip to sleeve of the microphone plug at 830 ohms. That message suggested that such a low resistance would be indicative of a dynamic microphone element. The headset works fine with Skype on a laptop if that means anything. I've got a mic plug and a female inline 1/8 socket and I will be making an adapter for the headset. I want to be able to change from the hand microphone to the headset without making internal changes on the K2, of course. Ideally, I would like to use the same 1/8 inch to 8-pin adapter for soundcard digital modes with the K2. What should I do about the bias on microphone pin 1? Should I just use the headset as-is, risking distorted audio with a dynamic microphone fed 5 volts of bias? Should I include a blocking capacitor (of what value?) in the adapter that I build? Thanks in advance for any advice you can offer. -Neil N0FN ______________________________________________________________ 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 Message delivered to arch...@mail-archive.com
