Why Expensive power Cables when Romex behind Wall?

Even though the cord is short, it still contributes to the overall inductance. ROMEX has up to 10 times the inductance of good after market power cords. If the the last 6 feet of a 20 foot run to the panel is an after-market cord, it will add very little to the inductance of the first 14 feet.

Systems reproduce upstream content using upstream power sources (except some battery powered phono pre-amps). In that regard we spend ridiculous amounts of money. But our systems are (hopefully) designed to do the best job possible with the presented content and power source. So we spend our money to minimize changing, or losing, the content and to doing the best it can using the power available. But I'm in the camp which says that with my upmarket equipment the equipment designers have designed their equipment based on the known vagries of the power source (one of the design decisions requires overspec-ed transformers for example). So what the hell. Let the equipment do the job it's designed to do.

Having said that I've upgraded my PCs ! Just in case. If nothing else I get a better connection to the romex. Sad really.

I always thought hospital grade just meant that it was designed not to produce any arcing when a plug is placed into the receptacle because of flammable gases that could be present in a hospital room?

Guys, if installing a supposedly high-quality power cord is actually producing audible differences in your system, then the power cord is not just passing the power without further distortion -- it's changing something. If your electric power supply is so bad that it needs to be filtered, then a power cord is NOT the way to achieve that objective -- you need a power regeneration system, such as those made by Richard Gray, PS Audio, Monster, etc. After you get the regenerator, THEN go for the good quality power cord.

(For the record, I also have high-quality power cords installed on most of my gear. These cords are probably the only "tweak" I've acquired that provided very little -- if any -- improvement in my system.)

Sdcampbell... Now that you are accustomed to your system's sound; ALL AT ONCE without listening; replace all of your cords with the typical black 18awg cords that come with most gear and computers. Then play your favorite most listened to recording. Does it really sound the same?? If you replaced the cords over a long period one at a time, you may not have noticed any change, since it was gradual.