I have also found that with a really good audiophile quality amp I don't hear a noticeable difference or perhaps just a tad of difference when trying different high-quality power cords. In this particular case, I'm talking about my Plinius SA Reference amp. I do hear a significant difference with my preamp, phono preamp, transport, Dac, and FM tuner.
We need someone like @almarg to explain this.
We need someone like @almarg to explain this.