[Collins] 32S-3 microphone

[Dr. Gerald N. Johnson]

On Sat, 2009-12-05 at 14:59 -0500, frankshughes at aim.com wrote:
> Hi,
> I am a new Collins owner, just received my first transmitter, a 32S-3. 
> I need some advice as to a microphone for it.
> I have read that a high impedance unit is required, and that there is 
> a special PJ-068 plug needed. 
> So what manufacturer /model of microphone should I buy and adapt to my new rig?
> What do most folks do for PTT? Rig a momentary switch on the mic.? Foot pedal?
> Or is it easier to use a hand mic. w/ a built-in PTT?

Most any unbalanced high impedance microphone will work. Some of the
better ones have a communications instead of music response curve, but
they will all work. EV 664 was one sold by Collins, others came from
Turner that are no longer made either. Shure 555 would be a good stand
microphone.

PTT isn't absolutely required, the VOX works well and some prefer to use
VOX instead of PTT. Contesters would often use a foot switch.

I have used a D-104 with a different cartridge to prevent its emphasis
on the highs and it comes usually with a G grip stand with PTT. For a
desk stand for the 664, I mounted a microswitch with a button in the
stand base. 

A Kenwood microphone made for the TS-120/130/820/830 era can be had as a
a hand microphone or a desk microphone and the desk microphone impedance
is selected by turning a connector around.

The impedance of the EV664 is selected by picking the pin for output on
the 4 pin connector at the microphone.

Most every electret microphone, when supplied with battery power, will
have plenty of output. Sure its low impedance but it has enough volts to
drive the high impedance input and that mismatch won't affect a solitary
thing. The Yamaha CM-500 headset seems like it would do that. I know its
comfortable for all day use on receive though I haven't yet hooked up
the microphone part.

The military/phone company PJ-068 plug is also known as a Switchcraft
S260 or S267 sold by Mouser for about $9.00. Used also on the Drake TR4.
And microphones that fit the TR4 may need to be reconnected but are
suitable for the 32S. The PJ-068 is less than a quarter inch diameter,
Mouser says 0.206" diameter.

I hadn't thought of using the rear panel connections but they are there
and they should work just fine.

In times past even Radio Shack has carried high impedance microphones
and transformers to convert a low impedance microphone to high impedance
for PA systems.
> 
> Thanks,
> Frank
> KJ4OLL


-- 
73, Jerry, K0CQ, Technical Advisor to the CRA
All content copyright Dr. Gerald N. Johnson, electrical engineer