I have an electrician coming out tomorrow, he’s going to give me an estimate for some isolated grounds.  other than this I’m clueless.  I’ve tried separating polarized adapters and grounded plugs…  but that got me thinking it was futile if there’s a loop running around my house wiring.  the only thing that didn’t make sense is why my last stereo fx unit didn’t seem to have this issue, but now I’m going on the assumption that maybe I DID have this issue but the H9 has made it more apparent because, well, my old preamp was really bad by todays standards.