When I bought my briefly-used Classé Audio SS power amps in the late '80s, the previous owner had already outfitted them with Cardas Quadlink power cables (a lower rung in their hierarchy). At some point I experimented with using some ordinary AC cable, and heard the difference immediately, and went back to using the Cardas. I don't recall the specifics, but generally Cardas cables seem to result in more robust bass that is easily noticeable if the system can reproduce it. My system, with a very fine Classé preamp and Apogee Duetta II ribbon speakers, was/is quite revealing. But I did not hear a difference when recently replacing the power cables on my Bluesound Node streamer or my Denafrips Ares II DAC with low-end Audioquest power cables.
So, I guess I'm in the camp that says AC cables make more of a difference with power amps than source components, although I'll admit my sample size is small.
The original owner of my Classé Audio gear, a dealer, was very enthusiastic about Cardas wire--not only did he replace the power cables with Cardas, but he replaced internal wiring on various products with Cardas wire.