I am not an audiophile, but I have had to clean up the sloppy power in my neighborhood. The transformer near me is very old and about to blow, but power company won't fix it. I've had to use a combination of isolation transformers, double-conversion Liebert UPS, step-start power distribution switches just to keep from losing internet every time the neighbors spetic pump kicks in. I also had to filter the RF cable as well, as it suffers from the same power spikes from cheap cable modems power supplies. Even my old Sony reference line receiver could not filter out that garbage. I'm in the middle of nowhere though, so this is probably not common for people in the city, just guessing.
Interesting. It appears to me that it's not simply a power quality issue anymore, it's likely that the old wiring and transformer winding is also arcing over, and creates enormous amount of wideband radio frequency interference, like a spark-gap transmitter, both in the airwaves and on the power lines. It seriously degrades any wireless communication and digital wired communication like DSL as well.
If you have a SDR capable of receiving shortwave below 30 MHz, try walking around the neighborhood with a laptop with a loop antenna connected to the SDR, and check the HF spectrum. It's likely that you'll see the entire bands being wiping out. If so, it's a serious violation of radio regulation, you can report the situation to the FCC.
No, I just complain to the power company a couple times per year. One of the neighbors also complains to them, as they smoked 2 of his UPS units. They burnt up a few of my cheaper UPS units prior to having the liebert double-conversion UPS. The 1200W APC caught fire. The other ones just smoked. The smaller APC units (power strip form factor) never smoked, they just tripped a lot.
I recommend installing surge suppression and overvoltage protection device at your home's main electrical panel. It won't improve your power quality or reduce interference, but it'll probably save your appliances from destruction...
I've done that too. I have a bank of 12 metal oxide varisitors. I forgot what each one is rated at, but they are big. They won't clamp until much higher voltage though. The double conversion UPS is between that sloppy power and the sensitive equipment. Prior to that, I lost 3 UPS units.
