[Elecraft] MH3 mic case

[Geert Jan de Groot]

> Does anyone know if Elecraft sell replacement cases for this expensive microphone? I've barely used mine (I'm a CW chap) and it's already fallen apart! The three plastic internal mounting pillars have snapped off. I guess it's been dropped, but only on to carpet and I'm minded to think a $70 mic should easily withstand that.
> 
> Last month I emailed Elecraft via their online parts order form, but not had an acknowledgement. Maybe they're all on summer leave?

Making forms for plastic moulding is extremely expensive and Elecraft 
did not make one specially for the MH3.

Looking on ebay, https://www.ebay.com/itm/281509579500 finds a 
microphone that uses the same case. The electronics inside is different 
(and, frankly, the MH3's innards are a lot nicer than these ebay 
microphones) but the casing is the same.
It has a different brand name on the case but that is only a sticker.

You can make these ebay microphones work by changing the wiring a bit, 
especially for the down/up buttonw. The radios these are sold for use 
resistors on the PTT line to signal up and down, on Elecraft they are 
direct connections.
And PTT and audio are on other pins so you need to change that too.

When I have the microphone plug open, I always add a 5K6 resistor 
between the 5V and the mic output in the plug. This power the electret 
microphone irrespective of "mic bias" settings in the menu. And it makes 
the same microphone also usable on the K2 (where the up and down buttons 
don't work, alas).

In defense of Elecraft, yes, their microphones are probably "also made 
in the east" but there is a difference in quality which will be quite 
visible when you compare them. Having said that, an electret microphone 
is an electret microphone and the reports on the air are not different.

And, if the round plug is change for, for instance th Neutrik NTP3RC 
(see https://www.neutrik.com/en/product/ntp3rc) then the same microphone 
will also work on the KX3. You will need to change the wiring to make 
the buttons work but that is not hard.

Geert Jan