Sunfire MK II lend a hand? Sunfire MK II Hums on input signal. Hum can
Sunfire MK II Hums on input signal. Hum can be canceled repeatedly by switching on or off lights contained by room. Problem is consistent. Sometimes a small electric shock can be felt at a street light switch. Is this a grounding problem? How important is a proper ground?
Answers: Yes, this is typically referred to as a 'ground hum'. You're audible range the frequency of the electricity.
What you can try to do is reconnect all your equipment to see if you can isolate what nouns is picking up the hum, then any change the cable out for a 'ground loop isolator' copy of that cable, or change to a optical cable which is immune to ground hum.
A small shock feel at the light switch sounds close to static discharge. All electrical recepticals are grounded.
If your electrical was done by a reputable electrician (not a do-it-yourselfer or broad contractor) then you can pretty much assure yourself that the problem isn't the electricity, it's ground hum from poorly designed equipment.
However, if you own any doubt about the sanctuary your home, I'd have a electrical inspector come over and check your electric wiring for any problems. This is a small cost to ensure you're home doesn't burn to the ground.
But the symptoms you describe are not unusual in any opening, it's just going to be a chore to step through all the discovery to find the problem equipment or cable surrounded by your setup.