what you are looking for is something that will eliminate voltage swings. the house voltage will be the same during the day as night. get a exactpower EP15A. i just put one in my system. all i can say is WOOOW !!!! there is two for sale as i post this on audiogon. they are $2500.00 new. there is a asking price of under $1200.00 in either silver or black. get one. no negatives like some power conditioners can have. most of these products induce noise into the system. this is what is making my system sound so much better. no voltage swings and less noise.the voltage stays at 120Vrms. no power conditioners needed as well. big improvement in sound. what TVAD is saying is how to describe what the EP15A does.
bill
bill