[Elecraft] DX Doubler/K3 issue

[k6rb at baymoon.com]

Just completed my second K3/100 and am in the process of integrating them
into the former FT-1000 SO2R station. I'm using the DX Doubler for SO2R
switching. I bought the K3 cables from them, and hooked up both radios to
DXD. When I plug the headset into the DXD phone socket, I hear a hummy
sidetone and low-level hum on both radios. With a headset plugged into
either the front or rear K3 phones sockets, I don't hear it. So, it sounds
like something that's occuring as a result of whatever's going on inside
the DXD. For now, I'm planning to isolate the audio output going to the
DXD using 1:1 isolation xfmrs. But has anyone else had a similar problem?
If so, how did you cure it?

I had a similar problem (and used the same solution) with the FT-1000s and
the DVD. I thought it was a Yaesu issue, but maybe not....

Rob K6RB