What difference do power cables make?

+2  @steakster / @facten    Some will always believe almost everything in Hi End Audio is "snake oil" a 40 year old Adcom amp with some repaired Goodwill 12 inch 3 ways is near SOTA!  IMO fear is holding most of them back which will forever keep them in mid fi purgatory.

None

@dayglow 

Vinnie Rossi is a US  manufecturer.

OP, I'm a relative novice here, so here's what I am sure about:

I have put in dedicated lines. This, I am certain, is the most important thing to do.
I have hospital grade outlets.
I have a decent Adept power conditioner, power strip, and a shunyata defender. All purchased used. This was the Almarg setup and he knew what he was doing.
https://audience-av.com/conditioners/ar2p/
 
I purchased cords from Pangea, used, which are appropriate gauges for my gear. 9 gauge for power amps and 14 gauge for front end. They were not expensive, relatively.

Do I hear a difference? I am not sure, but I know that I have at least done the minimum for my system in terms of the wire thickness and shielding.

Down the road, I may try:

(a) a regenerator
(b) more expensive power cords

but until I know that everything else worth spending money on -- room treatments! -- is done, I will not return to the power cord issue.

Why don't you get a few power cords from the cable company's lending library, it's a cheap way to try a few expensive cords and some lower cost ones and find out for yourself if there is a difference.