[Elecraft] Balanced Mic to Unbalanced Connection Follow Up, Question

[Dave B]

Both would work.

Sketch out the equivalent circuit and you'll see why.

As to using a TRS or TS 1/8th (3.5mm) plug, you'll have to consult the
radio's manual to see exactly what's connected to the tip and ring, and
if the sleeve is actually connected directly to the chassis, not via a
convoluted PCB ground trace.

Twisted pair's help cancel out hum and interference pickup, /only/ if
the input to the amp, mixer, or in this case the radio, is itself very
well balanced around "ground/chassis" etc.   As soon as you use it like
an unbalanced system, such advantages are lost.

But yes re the XLR Pin 1, that is a shield that should be connected to
the radio's chassis in either case.  Irrespective of what you do with
pin's 2 and 3...

73.

Dave G0WBX.


On 10/06/2020 00:27, elecraft-request at mailman.qth.net wrote:
> I have a follow-up question regarding balanced mics and unbalanced 
> connections. I'm about to connect a balanced dynamic microphone (Heil 
> PR-781) to the rear mic input on my K3S which has a 1/8" unbalanced mono 
> connection.
>
> One recommendation was to connect XLR pin #2 mic (+) to the tip of the 
> 1/8" jack and pin #3 mic (-) to the sleeve. In this case, pin #1 or 
> ground is left floating with no connection. A 1/8" mono jack was 
> recommended for this setup.
>
> The other recommendation was to connect pin #2 to the tip and pin #1 and 
> #3 to the sleeve of the 1/8" jack. It was also suggested that I can use 
> either a 1/8" mono or a stereo TRS jack in both cases.
>
> So which is correct?
>
> Tony -K2MO

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