I'm not sure what it did, but, I believe that cord (at the time) employed ribbon conductors of roughly 10 gauge with a very thin dielectric. The conductors were very close together, and I suspect this resulted in a high capacitance design. I wonder if this would be enough to alter the performance of the power supply in the amps, or if the high capacitance provided a bit of a boost of stored energy if needed, like a battery*... I don't know. But, your question did prompt me to dig out some power cords on hand. I did some quick measuring of the capacitance across the 2 prongs of the following 2 meter power cords:
PS Audio xStream Statement (6 gauge with 15 amp IEC) - 1.795 nf
ESP Essence (maybe 10 gauge? with 15 amp IEC) - .684 nf
12 gauge generic (from Audio Power with 20 amp IEC) - .400 nf
18 gauge generic (from VPI motor with 15 amp IEC) - .314
I'm not sure how capacitance might affect the sound, but, there's clearly a difference in the properties of these cords. It would be interesting to compare several gauges of a cord with the exact materials and construction to cut down on variables to see/hear if there is a significant difference.
I would think your idea of hardwiring the gear would be best, but, impractical in terms of flexibility.
*I wonder if this added capacitance could act like a smoothing or bypass cap and filter out some ripple or noise on the line.
That is exceedingly interesting!
Thanks for doing it.
If you've used those cords on the same equipment, any observations as to sound?
Totally, highly cool.
(It's tempting to buy a little capacitor and try it with a cheap cord...but I'm afraid I'd blow something up.)