[Elecraft] KX3: CM500 best price/use with

[john at kk9a.com]

I was also confused by the posts that the CM500 works best with bias off.
Thanks for explaining why this works only with the KX3/KX2.

John KK9A


Don Wilhelm wrote: 
Sat Nov 11 10:23:55 EST 2017

Yes, all electret microphones must have bias applied in some manner.
I am not certain why you think this is a KX3 "problem".
The tip and ring connected together is a characteristic of all 
microphones intended primarily for computer use - and the Yamaha CM500 
is one of those.  The ham microphones normally have a mono plug, and do 
not apply, although with mono plugs, MIC BTN must be turned off in the 
KX3/KX2 so that PTT is not activated when the mic plug is inserted (the 
shell grounds the PTT ring).
The normal computer jack applies bias to the ring, not the tip.
In the KX3, there is residual voltage from the MIC BTN circuit applied 
to the ring even with MIC BTN turned off - the combination of the tip 
and ring connected together and the residual voltage from the mic button 
circuit in the KX3/KX2 is why it works that way.

That is true of both the KX2 and KX3 - yes, it does not apply to the 
K3/K3S which has no connection to the ring contact in the jack.

So not a "problem", it is just the way things work.

73,
Don W3FPR