Best place to live for good quality power

@carlsbad2 - I live less than 1/2 mi from our electrical substation which may help explain the more consistent voltage and lower THD. I don't think there are any manufacturing operations (which tend to operate large motors) very close to me. I don't think I've ever seen the voltage less than 119 or more than 120.5, so it stays pretty consistent. 

I also have solar panels with an inverter connected to the grid. Not sure if that helps or hurts. 

I have my power plant set for minimum THD, so my output voltage is a touch higher at 121V, but also with 0.1% THD (this is probably the lowest it will report). 

Not much difference here with or without the Power Plant.

The location for clean power is not as important as how you bring it into your listening area and how separated it is from the rest of the living quarters. Another expensive endeavor, but what isn't in our hobby.

Might be a stupid question from lack of knowledge on function. All the people who are running battery power for clean low noise sources. Does the power not vary or degrade as the battery powers down? I look at a flashlight that gets dimmer and dimmer as the battery gets weaker. What am I missing here. Not being sarcastic would really like to know.

@sgreg1 Fancy modern battery power supply (like "Jackery") has regulators and complicated circuit that keeps that from happening. Because they are designed to power digital circuits, the power must be tightly regulated. But the true affect on audio is known only to the users. (I dont have one)