[Elecraft] Hum coupling?

[Ron D'Eau Claire]

Yep. Not only that, you'll have hum on the transmitted signal a well, Tom. 

I think there's a warning in the documentation to keep the K2 a way from
strong transformer fields. 

Three years ago I discovered hum on my K2 that went away every time I opened
it up to check things out. Maddening. Hum while operating then no hum while
investigating! 

Then I noticed the obvious. I was removing the K2 from its perch on top of
my power supply when I opened it up to look for the source of the hum...

I have an Astron 20 amp for my K2/100 and it sits on a stool UNDER the
operating table. That keeps the table clear for other things and keeps the
AC magnetic field out of the K2. 

Ron AC7AC

-----Original Message-----
I'm experiencing similar AC hum on the K2 audio.   The K2 sits on top of my
Titan II and when the HV is set to operate (kicking in the big HV xfmr
directly under the K2) I get the hum.  If I pick the K2 up and move it about
3" away from the Titan then all is well.

Has anyone else experienced hum from nearby power transformers?   I plan on
using a 10Amp analog supply (not here yet) and anticipate I might have to
keep it away from the K2.   I suspect switching supplies do not cause the
same effect.

Tom K2TA
Greenwood Lake, NY
K2 #1117