I saved this detailed note that was posted on this list a couple of years ago. Maybe Elecraft needs a KX3 FAQ with this info.
------------ Re: KX3 - Buzzing in headphones varies with MON level Posted By: kk7p Date: Wed Jun 20, 2012 12:49 pm I dragged out my CM-500 to test this. The CM-500 gets its mic bias from BOTH the tip and the ring of the gray mic connector. This is too bad, because the tip voltage is controlled by the MENU:MIC BIAS ON|OFF but the ring is always biased by the PTT/UP/DN logic supply. To get around the problem, do the following: 1) MENU" MIC BIAS OFF You will find you need a lot less Mic Gain for full ALC action. In my KX3, I need about 30 if BIAS is ON, and 17 if BIAS is OFF, for full ALC. 2) Since the PTT/UP/DN is a digital logic supply, it may have some residual noise that the CM-500 passes as audio to the tip of the connector. Go to MENU: TX GATE and tap "1" to turn it ON then adjust VFO A for 01 or 02, whatever it takes to kill the residual buzz. In the case of my KX3 + CM-500, this cured the problem. And in Dave's case, it might not cure the problem of noisy neighbors, but will allow the KX3 to better ignore them! 73, Lyle KK7P ---------- Thanks, Lyle. wunder K6WRU On Apr 19, 2014, at 9:27 AM, "[email protected]" <[email protected]> wrote: > I'm connecting a Yamaha CM500 headset to the KX3, and find that the > microphone works properly regardless of the MIC BIAS setting (MIC BTN is > set to OFF). > > As I recall, the few times I used the CM500 w/ the K3, the MIC BIAS had to > be ON or the microphone produced no output. > > Any idea why the MIC BIAS setting doesn't seem to matter w/ the KX3? > > 73, Dale > WA8SRA > > > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:[email protected] > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > Message delivered to [email protected] -- Walter Underwood [email protected] ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[email protected] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [email protected]
