[Elecraft] Microphone preamp and Heils

[Bernie Gardner]

I recently bought a Heil 'Handi-MIc' with the Icom element (designated
HM-IC).  It works fine without a preamp, but does need the resistor to
bias the electret element.  Rather than removing the front panel and
wiring the jumper, I just opened up the connector shell on the mic and
soldered the resistor between the appropriate pins on the connector.
(I'm away from home at the moment and don't have the diagram to tell
you which pins, but it's pretty easy to figure out.)  The microphone
seems to work very well.  I assume this would work with other Heil mics
with the Icom element.

Bernie
W1AZ


At 09:51 PM 2/14/2007, CMKaco at aol.com wrote:
>Hi, sorry if this repeats previous information request, but I did a lot of
>searching and didn't find anything directly on point (even though there were
>several threads on preamps and Heils, etc.)
>
>
>I downloaded the Microphone Pre-Amp for Heil  schematic on the Elecraft
>website.
>
>My questions are:
>1.  Does anybody make a PCB for this  project?  I imagine all these parts are
>available from Radio Shack  or Mouser?
>
>2.  Does the preamp make the microphones  work really well, or is it just
>something that "gets you  by?"
>
>3.  As far as Heil microphone modules go,  if I build the preamp, and want to
>buy the Classic, can I use any module, like  the Pro, HC-5, HC-4, etc., or
>should I get the ICOM only module, which I believe  is an electret 
>module.  I am
>a bit confused about all this.  I asked  Elecraft and they said I should get
>the electret module.  Bob Heil said the  Classic was not a good 
>choice for the
>K2 and he suggested his iCM mic for  ICOM.  Doesn't the iCM mic have the same
>electret element  that the Classic with the  IC element has?  If all I needed
>was  an electret element, do I need the preamp at all, or does it make the
>electret  work even better?
>
>4.  Once I build the preamp, is it  something that I can tuck into the
>microphone itself (like a Heil Classic) or  does it go inside the K2 
>or do I need to
>put it into it's own little  enclosure.
>
>Thanks for your help.  I am a new ham, and  am trying to sort through all
>this stuff.
>Christ Kacoyannakis
>K4CMK
>
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