Some manufacturers have great voltage regulation built into their products. My Burson PI-160 integrated has their own in house voltage regulators and gone are the days when I had to listen at night to get the best out of my system. It sounds the same all day long now. I live in an apartment and the competition for power had its negative effects until I came across this Burson. They claim less than 1% voltage fluctuation and I believe it. I've never heard anything so sound good.
And clean.
And clean.