@tweak1 My neighbor has a high end/cost system with YG Sonya 2.3s, subs, Bekerely USB, Meridian Ultradac, etc. He has high end ICs and speaker cable but was using Pangea power cables. As an electrical engineer, he didn't believe power cables could make a difference. His bass was terrible, frequency anomalies where a bass would play one not forward and the next up would be hidden, then in, then out. Terrible.
I lent him one older GroverHuffman Empress power cord for his amp and he heard the difference, a smoother frequency response in the bass. He opted to purchase six GroverHuffman Pharoah power cords. Now I can sit and listen to his system with pleasure as the sound is coherent, smooth/even frequency response. He also tweaked his Audio Research SP28 preamp by replacing the 6H30 tubes with 6N6/6H6 tubes. Sounds great now.