[Elecraft] K3 and SM20

[W6NEK]

Hello Barry,
If you connected the SM20's Pin 2 (+8V DC Input) to K3 front panel Mic Pin 6 
(8V Output) then the SM20 internal preamp will provide mic bias to the SM20 
electret element.  That's how I wired my SM20 and it works great on the K3. 
No additional Mic Bias is required.

73,
Frank - W6NEK

----- Original Message ----- 
From: "Barry Simpson" <vk2bj at optusnet.com.au>
To: "'Elecraft'" <elecraft at mailman.qth.net>
Sent: Tuesday, August 12, 2008 2:49 AM
Subject: [Elecraft] K3 and SM20


> In readiness to use my new K3 I have rewired my Icom SM20 mic to the K3
> configuration. I was surprised to find that it works exactly the same with
> the bias on or off. To ensure that K3 FP mic bias is performing correctly 
> I
> have also tried out my new Elecraft Heil Proset. That works fine with the
> bias on but not at all with the bias off which is what I would expect.

> I thought the SM20 required bias as it is an electret mic but that does 
> not
> appear to be the case.

> Has anyone got any experience of the SM20 with the K3 ?

> Barry Simpson  VK2BJ