hum from nearby high-tension wires?

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.

These aren't the monster tower kind of transmission lines for long distances, they are local distribution type within city limits that have lower emissions. The only devices affected are sensitive ones like phone preamps and pickups (and, I suppose possibly our nervous systems, although I wonder how EM radiation of this sort could have signifcant coupling with our electrochemical wetware, I seem to remember that our nerves conduct in a different way ("sodium pump"?) than metal wires).

Anyway, thanks for advice, I'll try the radio and fluorescent tube tests. My grandson would be thrilled if we could get the full lightsabre sound and audio effects.

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.)

plastic water pipe. Sigh.

Turned out to be a loose connection.

There was no radio noise, even right under the wires.

But now I know a lot more about grounding, thanks for the advice.

Jea48: I live in Santa Cruz, CA. I've called some local electricians, but so far I haven't invited anyone out yet because I want to research a little bit more.

Specifically, our house is on a hill that is a big rock. Dig down 8" and you hit this yellowish rock. This area used to be quarried for limestone. I think the type of geology is called "karst". The rock is not hard like granite, but it is hard enough that you need to chip at it with a pick to make any sort of hole.

The thing I'm wondering about is whether this rock (is it limestone?) has good grounding qualities. The local electricians I have called say they don't know and don't have the measurement tools to test, all they do is visually check compliance with local codes. Do you know if there is a lab somewhere I can send the rock for testing?

In my own visual inspection, I can see that we have just one ground rod, which appears to be just some rebar pounded into the ground; I don't know how deep it goes. The earthing strap is all corroded. So this definitely needs some attention!