I found the issue in the rotary switch of the primary guitar I was using, haven't tried the other guitar that had some buzzing, but the guitar I was playing last night was perfectly fine.
I think it is down to the rotary switch, PRS made it way back in 1994, told me the wiring and got the info backwards to where hot and ground were flipped.
There is some hiss in the background now, I've had it down to just headphones and guitar(s), input noise gate kills that.
Never got a notice of reply.