Sean, as is usual with his expertise, is right on the money.
Powerwedges and the early Brisson stuff were the first plc I experimented with and they made the system noticeably quieter. I did not find, that they reduced dynamics. I've also used Equi/Techs( balanced power= less noise) and the PS Audio stuff, to run US voltage equipment here in 230VAC country with no detrimental effects at all. With the Bybee powerconditioners I tried, I did not really notice much difference, neither with the Tice stuff. But I found the TAD, an early Bybee attempt, which is without current protective devices, subtly increased the dynamics on the preamp,(Spectral DMA 30) I used it with. I've never tried the really expensive Accuphase and Burmester gear, but I am very happy with the PS Audio 300 and 600, which also helped to make my system somehow subtly quieter and its rendering more "relaxed" and naturally musical.