hum from nearby high-tension wires?

Jea48: maybe 80 feet high. Insulator about the height of a large owl or hawk (maybe a foot?) (I often see them sitting on the line).

Dreadhead: well, consider that I live in an earthquake zone and commute some 75 mi per day; these are probably my biggest risks. And just being 49 years old has its risks - bell-curve-wise, many of me are already dead. I don't smoke, but I like wine; my cholesterol is moderate, but on the high side (along with my weight). And I drink tap water. EM from the power lines ranks below these other things on my list of threats to life.

At least I want to enjoy music while the radiation crisps my genetic material.

(Please note that I'm attempting to make light of the situation, I hope no one is offended by these off-hand remarks. All of us have had loved ones who have been affected by various unpleasant health issues, and I mean no disrepect, I'm just being flippant to put some emotional distance between me and the consequences of taking risks.)

Update: it may be due to poor grounding of the house. I found the ground spike, connections to it are corroded. Plus I found a degenerate cable connection that was not in use. Oddly, disconnecting this hidden cable connection actually made the hum louder. I need to get an expert in here to asses the house grounding.

Steverw...Please do the portable radio check. This would probably set some people's minds at ease about radiated EMF.

Just as I figured. You'd be amazed how many houses have bad grounds. Keep us posted on the repair.