Why power cable effect overall syste sound?

Bob_bundus, Apparently you have not been paying attention. This has nothing to do with being a "Doubting Thomas".
Even though this is a debate, it can still be an enjoyable debate without rude comments. I have noticed the rude comments are coming from the group who are the believers in the fact that these after-market power cords have actually improved their system. If you realize a true system improvement then there should be a certain level of confidence in the debate. Instead it seems the debate is fueled by doubt and buyer's remorse.
When exotic speaker wire first came on the market I told a friend about the improvement it make in my system. He laughed and said "right, it just speaker wire". I was not offended by his comments because knew what I heard.
I didn't need a technical explanation why it sounded better. I still don't care if it is 99.9999 pure oxygen free copper or silver coated copper or pure silver. I don't care what the dialectric is made of, if somebody froze it or if the spades were connected with some special solderless method. I don't care if it is multple strands or solid core. I don't care what the gauge is or if the jacket is pink or purple. Well, I might care if it is pink.
All I care about is if it sounds good in my system. And if it does sound good in my system, there is no guarantee it will sound good in yours.

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... ;)