Why power cable effect overall syste sound?


Power cables effect the system sound. This is a well-known fact. My question is why.. specially in case of low power type "A" amplifiers where current is constant. In my single ended 300B the cable creates huge difference. Does it points on power supply PSRR issue? Actually in case of well designed power supply, the power cable should not introduce any improvement. We are spending hundreds of dollars for the 1 meter of cable from outlet to IEG socket where meters of cheap wires running in the walls and it does work. The answer on this question is puzzling me.
abronfer
Rrog...well put. I heard a difference in my system...not day and night by any means...but audible nonetheless. More important is what sounded better and that was little nuances in some recordings that I had never heard before. What's even more of an eye opener or should I say ear opener is that I was not trying to hear these nuances...they just came forth. It was also a lot of fun to try something I had never owned before and not have to invest a bunch of money. Mainly b/c I don't have a lot of money. Will everybody that upgrades hear a difference...probably not as their rig is probably top notch anyways. Btw...the cables I tried are Signal and have no desire to investigate higher priced offerings from other manufacturers. I believe what is important and perhaps the best lesson here is that I am happy w/ my system and that's what counts the most.
Mnnc, I'm glad to hear you found something that improved your system without spending an arm and a leg. Happy listening.
This is why I'm trying to take my system off the grid. If the functional nature of all components is DC in nature, why introduce AC and all it's problems in the first place?

Thanks especially to Samuel for some of the enlightening explanations. I think it validates my approach even more. Now, if I could just find neutral IC & speaker cables... ;)