[Elecraft] Koss SB-45 Headset, update on comfort

[Augie "Gus" Hansen]

Hi Jim,

> Electret and dynamic mics are equally good for ham radio. Use whatever 
> comes with the headset you like and be happy. All that matters is that 
> electret mics need bias turned on and dynamic mics do not.

Do you know why Elecraft calls the power provided to an electret element 
BIAS? Unlike the large form condenser microphone elements that need both 
polarizing potential and preamp power, usually provided via a "phantom 
power" circuit, an electret element is permanently polarized. The power 
applied via the phantom circuit is actually providing only the drain 
voltage for the FET preamp in the electret microphone capsule, not any 
kind of biasing voltage.

Of course we have similar terminology used in systems that provide 
control voltages or operating power to remote equipment: The so-called 
BIAS-TEE used to inject and extract power over a coaxial cable, for 
example.

I haven't found any official documentation for these types of circuits 
that uses the BIAS moniker. Are there any references that you might 
point to?

Cheers,
Gus Hansen
KB0YH