I have found audible differences in interconnects and speaker cables that can be attributed to differences in design (twisted pair, quad, coaxial, etc.) and material (Teflon, OFC, OCC, etc.).
When it comes to power cables, however, it becomes a much harder sell. I've tried a number of after-market (Audioquest & Pangea) power cords and my Bryston B60R Integrated Amp doesn't care what I feed it with. Bryston and Pass Labs have long maintained that there is nothing to gain by replacing their stock power cord with an expensive "boutique" one. The robust design of their power supplies might well explain their position.
When it comes to power cables, however, it becomes a much harder sell. I've tried a number of after-market (Audioquest & Pangea) power cords and my Bryston B60R Integrated Amp doesn't care what I feed it with. Bryston and Pass Labs have long maintained that there is nothing to gain by replacing their stock power cord with an expensive "boutique" one. The robust design of their power supplies might well explain their position.