[Elecraft] K3 Ground Loop Issues using Ameritron ARB-704

[Paul Christensen]

> Unfortunately, the AL-82 and SB-200 both create a pseudo-neutral
> by placing high voltage bypass capacitors from each line to the
> chassis/ground.

Right.  The problem has been around at least since the early '30s.   For the 
caps used in the AL-82, that works out to about 0.5 mA of current per leg 
diverted to ground.   Possibly enough to cause audio problems, depending on 
shack grounding configurations.

Somewhat surprising, commercial RFI/EMI AC line filters (e.g., Corcom) use 
modular CM chokes, but also contain multiple HV bypass caps from line to 
ground.   I just checked Corcom's website and typical AC leakage from line 
to ground for their 10A series filters is ~ 1.5 mA @ 250VAC and these 
devices are routinely used in lab-grade instrumentation and audio 
equipment.<g>

Paul, W9AC