When I got the Hegel H390 broken in, I I bought the best Pangea high current cord and heard nothing different. I bought several Audience F3 cables and heard no difference. I bought AQ NRD4 (?) cables and heard no change. I have bought a few others also under $500 and have heard no difference.
I have a friend who is going to loan me some Clarus Crimson and Aqua power cords as well as some XLR’s to try. I’ll let you know if they sound different.