[Elecraft] K3 & MK2R+ audio hum issue

[Jim Harvey]

I just received my K3 yesterday and have it interfaced to my Microham MK2R+.
CW operation is perfect but I have some audio hum and distortion in the
monitor on SSB. I'm using a Heil Proset connected to the MK2R+. Joe, W4TV,
has given me some good suggestions but the problem is still there. Is there
anyone else using this combination that can help?

 

Jim N0AV