Cable Costs Relative to System

"09-16-06: Sksos
I'll throw-in my 2 cents worth (maybe it's already been said, I didn't read all 135 responses up to this point!). Power cords can make or break a system IMHO."

I've asked before and will again; how can changing the last few feet of power cable in a chain of many miles from the power company, via various substations, power lines and your house wiring, possibly change how your system sounds?
Uninteruptable power supplies and conditioners I can understand. But suggesting that 3 feet of "special" power cord can improve an audio setup seems absurd. It's like saying that if your water supply comes via 10 miles of dirty pipes, then replacing the last 3 feet with new pure copper piping will suddenly make the water pure again.
If anyone can give an explanation better than "I've tried several and I can hear the difference", then I'm happy to stand corrected.

I appreciate the replies, but they still don't explain the apparent affect on the sound of a system. Once plugged into a wall socket, the power cable acts simply as a continuation of the power path from generation to your component's power supply (transformer etc); it isn't a discrete separate circuit as you suggest, in the way a power conditioner or UPS would be. It can therefore at best cause no further degredation to the power supply, but even a decent inexpensive cable will impart little to those two or three last feet.
As for RF/EM interference... yes, they exist and are a problem for low level signals in interconnects. But shielding less than 1% of your power supply chain is a bit like putting sunscreen on one finger and expecting the rest of your body to not get sunburnt.
I'm not trying to cause trouble here; I really am after some genuine evidence. But everytime I read "I spent $1000 on a power cord and Wow!", it sounds like "I spent $1000 on a power cord and it sounds no different but I don't want to admit I got conned by the HiFi shop."

I'm afraid I'll just have to wait for someone who does have the time to post some evidence. It must be nice to have endless funds to experiment with many different power cords "no matter how much they cost" and "custom made to my specs" as Joeyboynj does, but many of us need a little more than faith to spend hundreds or thousands of dollars on a power cord that may or may not do anything to an audio system.

Once again, if anyone can direct me to any research/evidence on this topic, I'll happily be educated and corrected.

To Ridgestreetaudio, I appreciate all your replies, and I take on board the fact that many audiophiles genuinely hear a difference with every tweak they make to their system; I recently upgraded my speaker cables and can hear a definite improvement to my system's dynamics and a crisper top end. My argument doesn't apply to speaker cables and interconnects.

I guess my issue with power cords is this:
If you look at speaker cables, these form the entire link between amplifier and speaker, and therefore their impact on the signal can be profound. A PC, on the other hand, constitutes only a fraction of the AC power "loop" that extends all the way from the power generator to your components - an extension cord, in effect - and I therefore can't see how it can possibly impact on a system's sound. Not to mention the fact that the power supplies within high end gear should be able to have a greater smoothing and calming effect on the power supply than a few feet of power cord.

However, I will endeavour to listen and compare PC's when I can and trust my ears, which is I guess all any of us can do.

Thanks for an interesting debate.

Hi RidgeStreetAudio, I guess my definition of a tweak is altering the existing equipment in some way to make an incremental improvement. Replacing the supplied PC with an aftermarket upgrade is in my view a "tweak", just as upgrading speaker cables and interconnects from what you already have to something that performs better is a tweak.
I realise a power cable is equipment in the sense that the component wont work without it, but upgrading to something better (and usually more expensive) is a tweak.