I've been reading a lot about "high-end" mains cords, and I thought i'd share some info from an electronic engineers viewpoint.

First of all, i'm not sure how one or two metres of expensive cable is supposed to make much of a difference over a cable distance of a few kilometres. Think about how the power got to the powerpoint in the first place. I don't think that many power supply grids are wired using audiophile mains cable! Add this to the "cheepest they could find" cable the electrician used for wiring the house. The two metres of audiophile mains cord is, at this point, seeming futile.

Lets assume that you live in a city wired completely from the power station to the houses with audiophile cable, and that the electricians all used the same. Alternatively, lets assume that you use a power filter (after all, the power station probably produces a lot of electrical noise over the supply anyway). You now have to understand the type of current you're dealing with. ac. ac power is ussually 50Hz or 60Hz - right in the low audio range. It is therefore noise in itself (yes, that power you paid so much to protect for two metres is noise anyway). The manufacturers are well aware of this problem, of course, and therefore after rectification to DC they use filtering in the form of capacitors and sometimes inductors. The capacitors compensate for the dips in the rectified voltage which removes the ac noise. The better the filtering in the power supply stage, the cleaner the available voltage rails for the amp.

To cut a long story short, the $500 and up two metre lead doesn't have a hope of making any difference, however improving the filtering of the power supply rails could prove very worthwhile (providing the manufacturer has not already gone to a lot of effort in this area - most can be improved!). Power supply mods are also fairly inexpensive.