Why Expensive power Cables when Romex behind Wall?

I believe Sdcampbell is correct. At least to a good extent. I had a demo'ed a few power cords and owned a Cardas Reference power cord which came with my amp and is/was a decent middle of the road.

I ended up demo'ing and then buying three (one for each component) used Foundation Research in line power conditioners, LC-1's and an LC-2. These in-line power conditioners replace the power cord and IMO do far more to lower the noise floor, enhance 3D soundstaging, and sibilants and cost about the same as some good power cords.

That would be my recommended route.

BECAUSE there is a low grade cable behind your outlet and because it works. You don't question why a water filter works after your tap water travels 100 miles through some nasty pipe, it is similar with good power cords although not exactly analagous. Some people think that the power cord is the same as adding a few feet of pipe to an existing pipe, but such a pipe simply would not impede water flow, whereas a power cord can improve signal flow, filter grunge, lower distortion due to better grade materials. Just try one under $200 that can be easily resold if you don't like it. One audition beats a hundred debates in the posts. SD I respectfully disagree based upon personal experience, having been skeptical myself.

The logic of some above would make the use of fuel filters in
the car you drive.....well, stupid....ie: the gas you get is
so dirty..why try to clean it.

Or...the fruits, etc., you buy travel so many miles...why
wash them before you eat them?

Listen up guys........saying the cables you use in the last
link of the chain doesn't matter is like saying that the
signal broadcast by your local FM station is all there is..and that there is no difference in tuners......

Any link in a chain can be improved...and part of the high-
end is the fine tuning... This is what high-end wines, cars
and many other "things" in life are all about, that last
% of performance....without this pursuit by some very, very
good people..we could all be loving the sound of our 8-track
tapes.

This is an old subject. Just try a high grade power cord, borrow one from a friend or dealer. If you can hear the difference, great, if not, fine. I heard, and hear a major difference, major. There are many on the gon' that can give you theory about this. I simply tried it and was blown away.

I agree with Sdcampbell wholeheartedly.