[Elecraft] SOLVED Radiosport MH-350ADJ with K2?

[Steve Dyer]

Thanks Don, I already knew the basics of a resistor between pin 1 and 6 
from a simple google search, but I suspected there was more to the story 
with the Radiosport headset. And there is.

After conferring with Dave, WI6R and super helpful owner, there is 
already a resistor inside the CS6-ELK cable and two dip switches to 
control whether to provide bias to the mic element. Some blocking and 
filtering is also part of the circuit.

The only thing I needed to do to the radio was to wire wrap from pin 6 
to pin 5 on the K2 mic header to provide 5V at the mic jack pin 5 in the 
fashion of a Kenwood radio. Pin 6 was not connected at the mic jack. The 
CS6-ELK cable needs the provided bias to act like a Kenwood, not a K2.

Then set the DIP switches and it works great. Now 1 cable and 1 mic 
element for both the K2 and K3!

I've copied the circuit image inline, I just don't know if the reflector 
filters them out. If so, be happy to email it direct.

Yet another reason why the RS headsets are so darn good and well thought 
out.

73,

Steve
W1SRD



On 7/26/2020 4:39 PM, Don Wilhelm wrote:
> Steve,
>
> I am not familiar with that particular mic element, but --
>
> If that is a dynamic mic element, no resistor should be used.
> If it is an electret type, the normal 5.6k resistor should work fine, 
> it is not critical - anything between 5.6k and 10k will do fine.
>
> 73,
> Don W3FPR
>
> On 7/26/2020 7:01 PM, Steve Dyer W1SRD via Elecraft wrote:
>> Is anyone using this mic element with the K2? If so, what size 
>> resistor did you use between MIC pin 1 and 6?