Why Expensive power Cables when Romex behind Wall?

If one thinks it makes an improvement to the sonics, of his system, then why not? If you have a $1000-$3000 to invest, to improve a $100,000 system, then it makes good sense. Where it doesn't make sense, in when that $300-$800, is spent on a PC, when it would make a much greater improvement, being spent elsewhere, in a $3500-$7000 system ie; room acoustics, dedicated lines, etc.

Fletchj, I could not agree more.

I also agree Fletchj for a small system; but will add that simply replacing those OEM 18 AWG cords with similar 14 AWG ones ($6 each), or the Belden Voltex shielded cables ($12 to $15 each) will still have a noticeable change for a few pennies.

I agree that relatively nominal amounts of hifi budget may be far better spent on room treatments than on the "upper level" (in price)powercords. I think part of the reason this doesn't always happen is that it is very easy to buy a PC and swap it out with the stock cord. What isn't easy is figuring out what room treatments to do, in what combination, and with what materials to address specific sonic problems.

That being said, I think there IS benefit in going with a "decent" upgrade to the power cord, but no real benefit in going hog wild on, say, a $500+ PC, unless of course you have more money than sense and don't mind lining a few pockets other than your own. I have Harmonic Tech and Ensemble PC's and they did improve the sonics of my system over the stock wire. However, I tried several more expensive cords recently (which shall remain nameless in THIS thread) and could not tell much, if any, difference.

I once read an article about using home electrical wires for networking all the computers/control devices in a home togeather. The article went into all the well known sources for noise on the power lines and how the carrier waves were tuned to the higher frequencies to avoid all the garbage. It could be that the high dollar cables are simply acting as high pass filters for the electric signal. Different cable sound then being the result of different filtering, much like a parametric eq for power but with each cord having its own eq shape.