Thanks Paul and Doc for such quick responses.
I know I'm not giving you much to go on, but we need challenges in our life Doc...
Brand new batteries, of rechargeable variety if that matters.
I'll see if he's up to measuring voltages...
He did say the hum+buzz gets louder when reaching for the volume pot. Also tried using long cables to keep Quickie away from the wall powered components.
Says he's pretty good at troubleshooting, so we'll see.
Sounds like grounding issues to me, but Paul is probably right not a good match with the BK ST-140.
Perhaps Quickie will be returning to the great northwest....
Cheers
Craig in Seattle