> What is surprising, however, is that everything works equally well
> whether MIC BIAS is On or Off.
Bias to the electret element is not supplied by mic line - it's supplied
from the tone generator IC! The tone generator supplies voltage when
no buttons are pushed which enables the mic. When a button is pushed,
mic voltage goes away and the PTT circuit is enabled.
I would have thought that the voltage on pin-6 of the front panel
socket would have gone off when MIC BIAS is set to Off, but that is
evidently not the case.
K3 Mic bias is DC on the mic audio line (pin 1). It has no effect
on pin 6.
73,
... Joe, W4TV
On 2/8/2018 5:23 AM, David Pratt wrote:
I am delighted to report back that changing the wire from pin-5 to pin-6
has done the trick. DTMF tones work fine on the K3 as do also the UP and
DOWN buttons with MIC BTN On in the CONFIG menu. The DTMF tones also
work on the K2.
What is surprising, however, is that everything works equally well
whether MIC BIAS is On or Off. I would have thought that the voltage on
pin-6 of the front panel socket would have gone off when MIC BIAS is set
to Off, but that is evidently not the case.
Thank you again, Joe.
73 de David G4DMP
In a recent message, "Joe Subich, W4TV" <li...@subich.com> writes
Elecraft and Kenwood reverse the pin used for +8V that powers
the DTMF encoder. You will need to move the wire on pin 5 of
the Kenwood Foster plug to pin 6 to get the +8V from K3/K3s.
The same is true if you want to use a Kenwood desk mic with
built-in preamp or active equalizer (e.g., MC-60A, MC-80, MC-85,
etc.) with the preamp or eq.
73,
... Joe, W4TV
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