[Elecraft] Desk Mike for the K3 Question

[Chuck - AE4CW]

Jim, I wrote this response based on my experience with my K3.  I agree, the
direct connection to the front panel mic connector should work fine, but I
had a transformer on hand and wanted to use the rear mic connector where a
chassis ground is not as easily available.  This connection has worked very
well in a high RF environment with no problems whatsoever.

Re the Shure SM58 style mics: as cardioids, they are subject to proximity
effect but largely to the extent you "eat the mic".  At more reasonable
distances of 1-2 inches I don't find it a problem at all.  I also like the
noise reduction from amplifier fans the cardiod pattern affords.  Coupled
with the K3 TX equalizer where I roll off everything below 400 Hz and boost
to varying levels at 1600 Hz and above, I personally find the results equal
to or better than any other mics I have used on the K3.

Of course, a simple computer headset electret mic can also work very well
and cost next to nothing!

Chuck, AE4CW


Jim Brown-10 wrote:
> 
> On Thu, 27 Nov 2008 15:57:11 -0800 (PST), Chuck - AE4CW wrote:
> 
>>The output is XLR low-impedance
>>balanced, so you will need an in-line transformer to convert to the K3's
>>unbalanced input (available from Radio Shack and Frey's).
> 
> NO, NO, NO! 
> 
> You do NOT need a transformer -- in fact, should NOT use a transformer. A 
> balanced mic has two hots and a shield. To connect it to an unbalanced 
> input, wire one "hot" to "hot" in the radio, the other hot to "mic 
> return" in the radio, and the cable shield to the chassis (the shell of 
> the front panel mic connector). 
> 
> http://audiosystemsgroup.com/HamInterfacing.pdf
> 
> http://audiosystemsgroup.com/RFI-Ham.pdf 
> 
> Also, the standard "ball mics" that look like SM58s are NOT a great choice 
> for ham radio because they are simple cardioids that have proxmity effect 
> (bass boost when used close-up). Some far better choices are listed in the 
> pdf above. 
> 
> 73,
> 
> Jim Brown
> K9YC
> 
> 
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