[Elecraft] K3 and SM20

[David Woolley (E.L)]

Jim Brown wrote:
> On Fri, 15 Aug 2008 08:04:31 +0100, David Woolley (E.L) wrote:
> 
>> Condenser microphones, that were historically used as broadcast 
>> microphones, 
> 
> Condenser mics have historically been used for MUSIC, both 
> recording and broadcast (and they still are). Most broadcasters use 

Thanks for the clarification; my memory was a bit shaky on the exact 
scope of use.

> Electret condenser mics need a different form of bias. The capsule 
> (the transducer) is permanantly biased when it is manufactured -- 
> it doesn't need anything from the circuitry. The very small signal 
> produced by the capsule is amplified, usually by a FET follower 
> circuit. This amplifier circuit is what needs DC voltage and 
> current from the radio.  

I'm not clear how this differs from what I said.  The FET follower is 
the pre-amplifier that I was talking about.
> 

-- 
David Woolley
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