cable upgrades , real or rip off


im sure this has been done to death on other threads, but im somewhat new to the high end audio thing. but i must ask do these items make a huge diff. , a small one or something in between. i cant help but asking myself why when a company is trying to produce a knockout item such as a intgrated amp that costs say 3000.00 would they skimp on something like a 300.00 powercord if it would make there product sound that much better?
jrw40
again thanks for the feedback, i can tell from the wide range of responces that this is not an open or closed debate. i did however find bigtee's blind test very intresting.
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I think Elizabeth is correct, that is until one reaches the point where changing equipment represents more of a horizontal movement than a vertical improvement.

At that point, a system, regardless of its specific make up (of components, speakers, cartridges, etc) is definitely capable of revealing the very real differences in cabling. And so I believe that is the time to begin this exploration, and probably not before. I also believe that at this point in system development, no further changes should be made in equipment until the cabling is brought up to a similar level as (the already high quality level of) the equipment.
I'd rate the cable importance in this order.
1 - IC from source to pre
2 - IC from pre to amp
3 - Speaker cables
4 - Power Line conditioners(not cables but still relate)
5 - Power cords

The best interconnect should reside between your source and your preamp(or integrated).
And by the way, good cables make a difference once the rest of your system is good enough to show it. Otherwise with crappy components don't expect difference between cables to be big or to exist at all.