I just got a used Mesa Nomad, and man does it hum...hums with nothing plugged in at all, increases with volume turned up, and picks up radio stations when the master is cranked...so far, it seems completely independent of preamp settings/channel. Guitar volume changes don't affect the hum at all. I tried a known good tube in V1, as well as different power tubes. I've tried it in different outlets, in different rooms. I've done it without my pedal board, as that was the culprit with my Kustom hum issues. Recommendations? Anyone recommend a decent tech in Cincy/Northern KY? Thanks!