[Elecraft] Yaesu SSM-17A mic with KX2?

[Geert Jan de Groot]

Hello,

If the Amazon microphone is anything like the other Asian microphones I 
have seen and modified, things will actually get slightly more 
difficult. Please bear with me, this gets complicated.

Elecraft suggests to use an angled 3.5mm connector for the microphone to 
reduce stress on the microphone connector. And one would think the plug 
on the Amazon microphone you have will work, but prepare to be disappointed.

A 4-pin 3.5mm KX2 microphone connector has 4 connections:
TIP for the microphone signal
RING1 for the PTT / UP / DOWN signal
RING2 GND for the PTT contact
SLEEVE GND for the microphone signal

On KX2, PTT is a contact between RING1 and RING2.
In case you're interested, the UP / DOWN is also a contact between RING1 
and RING2, but with 4K7 or 10K in series

On Yaesu, things are different. If memory serves, TIP is the microphone, 
the PTT contact provides a DC path (in series with the microphone 
element, both are between TIP and SLEEVE.
Yaesu also allows the microphone to function as speaker, between RING2 
and SLEEVE.

One would say "just open the microphone and re-wire", but, no. You will 
see that there will be 4 wires coming from the cable, but, if your 
microphone is anything like the ones I modified, you will find that none 
of the 4 wires from the microphone connector connects to RING1.
You read that right: no connection to RING1, hence no PTT contact 
possible. You will not be able to create a PTT signal with the existing 
3.5mm connector.

You will have no recourse but to cut off the angled 4-pin connector 
(snif!) and replace it with something else. I have used Neutrik NTP3RC, 
which is an angled 3.5mm connector and is robust. You will notice that 
it does not have a separate RING2 but since RING2 is the same connection 
as SLEEVE, I have used SLEEVE as GND for both PTT (against RING1) and 
MIC (against TIP). That works OK.

You will need to do a re-wire job, but that is not too hard. Note that 
the Asian manufacturers don't use shielded wire for the MIC cable 
either, just FYI.

What I have done is to use the Neutrik, re-wired the microphone, and if 
you're up to it, change the wiring of the UP and DOWN buttons to give 
PTT via 4K7 or 10K as described earlier.

It is a bit of a sunday afternoon construction job but it will result in 
a microphone that works. The other "mod" I have done is removing the 
speaker (which serves no function when used for KX2) and moved the 
electric element from the crappy place it is, to the place where the 
speaker used to be (fill up with some foam for mechanical stability as 
well as audio quality).

It will result in a microphone that works, and works well. Don't forget 
to enable the microphone BIAS in the KX2 settings to make the electret 
element work.

73,

Geert Jan PE1HZG