Out of morbid curiosity, I read every post in this thread, from beginning to end.
Scary, very scary.
Theoretically, with all that is known scientifically, in this world about electron theory, RFI, etc. the last two meters of wire supplying 120/220VAC to one's power supplies, cannot make any difference whatsoever in the resultant "sound" of one's audio system.
It is a given that the wire is capable of carrying the current needed so as not to suffer from I/R drop. With any headphone system, 22Ga. copper should be sufficient.
If the afformentioned 2 meters of power cord contains filtering components either lumped sum, or discrete, such as ferrite chokes to remove RFI hash picked up in the previous 10km of wire to one's abode, then yes, there may be some improvement to be had, particularly if the power supplies in one's equipment are poorly designed in the first place.
All of that said, I did an unscientific experiment comparing a cheap stock type power cord to an expensive (for me) $99 power cord. The expensive cord claimed only to have the finest wire inside of it. The expensive cord claimed to be foil shielded. The wire claimed to have no additional RFI filtering in it's design.
These two power cords were used to power my HR MAX, which to my understanding, has a very well designed power supply.
Against all scientific knowledge and theory, subjectively, I heard a difference between the cords. To me, with the $99 cord, the sound had more "blackness" between instruments, better inner detail in the music, etc.
Make sure you read and understand my use of the word "subjective" and "unscientific" in my post.
Besides all of that, the fat, garden hose sized, power cord going into the back of the Max looked really cool. Did the aesthetics and psychology of that big beefy 10 Ga. power cord influence what I thought I was hearing? Ya, probably. I kept it anyway, 'cause it still looks cool coming out of the back of the Max.