Power cords


Is there any truth to the following which, as you can tell from the quotation marks, is not my brainchild (my brain is childless...). I picked it up from the site of a well respected amplifier manufacturer and trust I am not committing some sort of legal or moral transgression by reproducing it here:
"When you plug your power cord into the wall outlet you are in 'SERIES' with all the wire on the other side of the wall all the way back to the power source. The small length of power cord from the wall to the amp is insignificant compared to the miles of wire it is connected to. As long as the power cord can deliver the current and voltage required to drive the amplifier to full power it is as good as it can get."
pbb
The general consensus is that power cords do make a difference (I have been convinced many times over). You may have several feet of Romex in series but...
The same can be said about the cheap appliance wire used in speakers and we all know that speaker cables make real improvements.
Being somewhat skeptical, I chose to make my own PCs AND dedicated lines at the same time from Belden 83802, which is 12AWG/2 with shield, using only FEP (Teflon) as insulation. So the 30-50 feet from my service panel is ONLY this stuff. At $2/ft it was easy to make a separate line for the CDP, pre, and two for the monos.
I must say I hear a difference. My already-dead-quiet system seems clearer, cleaner, maybe a bit more dynamic. No spectral shifts (fortunately). Differences in interconnects are now more readily discernible.
I might buy another 100 ft spool of this stuff if any of you want some for lines or cables. $2.50/ft if I do it.
I think there's somebody out there selling it for $3/ft.
100 ft spool sells for about $200 shipped.
I don't really buy this notion about 6 feet of PC "resonance" that has an effect on the system downstream.
Changing ALL of it to clean copper in Teflon inexpensively just seems like a simple semi-scientific no-brainer without all the high-priced alchemy. Cheers. Ernie
Would like to think power cable is part of you power supply CKT. The resistance, capacitiance, inductance, and RF shielding on the input side of your transformer may play a subtle role of affecting the regulated voltage in your amp or DAC. And the result is it sounds different for different cable/amp&DAC combo.

Can't figure out a simple equation or ... for a useful engineering prediction. If somebody knows, please post.