Back to the OP Question about the hum. I once had a large amp, big transformer, large caps, etc. . . That's a lot of reserve to energize. I know this Q is old.
But I would occassionally run into a similar problem, turns out during the hottest summer days. Called the amp mfg. thinking it was a cap or transformer. Discussed several times and eventually concluded it was a combination of a lack of power supply in my house and the very hot and humid summer days - causing everybody in town to run their ACs. Lot's of draw which seemed to result in the power reserves having a tough time staying or getting fully charged up.
Power usage in neighborhoods is up in the mornings - curling irons, coffee pots, hot water heaters, hair dryers - all energy consuming devices. Perhaps a correlation?
But I would occassionally run into a similar problem, turns out during the hottest summer days. Called the amp mfg. thinking it was a cap or transformer. Discussed several times and eventually concluded it was a combination of a lack of power supply in my house and the very hot and humid summer days - causing everybody in town to run their ACs. Lot's of draw which seemed to result in the power reserves having a tough time staying or getting fully charged up.
Power usage in neighborhoods is up in the mornings - curling irons, coffee pots, hot water heaters, hair dryers - all energy consuming devices. Perhaps a correlation?