My amp is plugged directly into the wall (direct line). I recently tried an IsoTech Titan. A power conditioner made for amps. I tried it on my ARC Ref 160s amp. I found the soundstage lost depth and the stage was pulled forward and presentation was a bit less relaxed. Not a positive improvement.
I do not want anyone to misconstrue this to mean it may not be a great improvement for you. My audio dealer and I talked through several other homes he had put it in… in most, it was a noticable improvement. I guess in addition to conditioning, it stores power to stabilize the supply. But, I think I have a pretty good source. Although the AQ Hurricane power cord was a big improvement. Like all this stuff… you just have to try it.