[Elecraft] Using dynamic mic on KX-3?

[Don Wilhelm]

Kevin,

I have not looked into the DX Engineering adapter to see how it is 
wired.  You should get that information from DXE.

What is apparently conflicting advice comes from the fact that all Heil 
ProSets are not equal and not all are supplied with an adapter.  There 
are 2 basic types, one (like the Elecraft ProSet-K2 and the Heil 
ProSet-iC) use electret elements which need bias like your MH3.  Others 
use a dynamic element and should not have bias applied.

With that being said, take a look at the microphone plug on your ProSet 
- is it a mono plug (most are), and then look at the KX3 microphone jack 
pinout in the KX3 manual.  When using an adapter such as the one from 
DXE, you have to look at the wiring for the adapter as well.

Note that the KX3 microphone jack is a 4 circuit jack.  The tip is AF, 
and the Sleeve is the shield (AF return).  But the Ring1 and Ring2 will 
be shorted to the shield (Ground) by a mono plug.

To prevent the KX3 from going into transmit when you insert a mono plug, 
you will have to turn MIC BTN to OFF.

If you have an adapter, you may be able to leave MIC BTN set to PTT. 
Furthmore IF your microphone has a stereo (3 conductor) plug, then you 
can leave MIC BTN set to PTT if your microphone cable has an input for a 
PTT switch.

What I am saying is that you have to compare the wiring of the mic plug 
on the Heil mic with the wiring of the KX3 mic jack.

Since you are using the adapter from DXE, they should be able to provide 
the best information to you.

73,
Don W3FPR


On 11/9/2019 4:13 PM, Kevin Zembower via Elecraft wrote:
> Hello, new subscriber here. Thanks for setting up this list.
> 
> I'm trying to connect a Heil Pro Set Elite headphones and mic to a KX-3. 
> I'm confused by what I'm thinking is conflicting advice. The Heil mic 
> has a dynamic element, while the KX-3 is normally used with the MH-3 mic 
> with an electret element requiring bias voltage. I'm using the 
> HLN-AD-1-KX3 adapter from DXEngineering to connect them.
>