[Elecraft] Microphone Setup Confusion

[Jim Brown]

On 5/16/2023 6:40 PM, Alan Geller via Elecraft wrote:
> Is what Elecraft calls mike “bias” in the K3 and K3s Owners handbooks
> Equivalent to the “48 volt ghost voltage” required for condenser mikes et al
> In the broadcast and music industry ?

Yes, both provide power for active electronics that boost the mic 
element's output and make an impedance transformation (the mic element 
is VERY high Z) to drive the mic preamp (in the case of the unbalanced 
mics used in ham radio), or to drive a long length of cable (for 
balanced pro mics).

The two systems are very different though -- the bias circuitry used for 
unbalanced electret mic elements won't work for balanced pro mics, and 
the "phantom power," a positive DC voltage applied equally to both sides 
of the balanced cable (pins 2 and 3) with negative to the cable shield 
(pin 1) won't work with unbalanced electret elements. Those pro mics 
have a gain stage and low-Z balanced line driver built into them, which 
operates from phantom power.

Indeed, there are unbalanced, capsule-only versions of miniature pro 
mics that are used with wireless mics, using the same unbalanced "bias" 
method we use in ham radio, and the bias is provided by the wireless 
transmitter. This is what you're seeing with clip-on mics worn by on-air 
people, and by musicians with clip-on mics.

73, Jim K9YC