Don it begs the question what does "standard" mean to you as stated in the above posts. To me standard means zip cord like that attached to my household lamp.
Not my area of expertise, far too long ago when I was a licensed electrician, and not something I have spent much time researching. Standard as in whatever is typically shipped with the equipment, which I assume meets various UK/IEC/NEC/etc. standards, but I was not using "standard" in the sense of a specific engineering standardized specification. These are typically heavy-gauge twisted wires (usually three for hot, neutral, and safety ground) with a protective outer sheaf. Which means I have to concede your point; these are not "audiophile" power cords, but are a clear step above zip cord, that is true. The twisting provides some measure of common-mode noise rejection that simple zip cord does not.
In a house, power lines are sometimes twisted pairs (or triads), but often flat Romex or similar, usually not in conduit (not required in-house). All the noise can couple up to that last three feet or whatever, and of course there is loss getting from power plant to your outlet, thus the last three feet argument. A counter is that, if the power cord includes filtering at the point of service, then you can make the argument that the power cord is a line filter applied just before the power goes into the component. I do not think it is a very good argument from the point of view of designing a well-engineered design, and there are better ways and places to filter, but it is a valid point. That said, I have very rarely seen filtering included in a power cord, and none of the test equipment in our lab has such cords.
One other reason a good power cord can benefit a system, other than just replacing a grossly underrated cord (too light for the current flow), is by providing a better ground path. Some cords use a very light safety ground wire since it normally carries essentially no current. A heavier ground wire provides a lower impedance path to the outlet ground, which may or may not be beneficial for things like ground loops.
Commercial installs may use more conduit, especially where shielding is needed for noise or protection (of users and/or equipment). I have a friend who's career was power electronics and he spent the last decade or three working with hospitals. The wires are not really anything special but a lot of attention is paid to putting them in conduit, taking great care in outlets (locking), and generally making sure power integrity is maintained. He helped build screen rooms for things like MRI and PET scanners as well as some of the bigger ultrasound units (a lot of folk might not realize that "ultra" is way up there, like 60 MHz carriers). It doesn't take a thousand-dollar power cord but it takes darn good engineering.
So for me there are benefits to be had of the power cord is not up to its task, but buying the $10 cord instead of the $1 Wal-Mart version is usually enough of an upgrade for my ears of clay, at least for my audio system.
BTW, similar arguments can be made for power outlets, where higher-end versions may include filtering and make more positive connection to the plug. Unless you are running kW of power and/or have badly oxidized or loose sockets you are unlikely to hear any difference IMO, and again a good industrial grade plug is probably all that is needed.
Like so many things in audio, science can be used to prove or disprove most anything, but you will never prove anything to someone (not you Gregg, a generic "someone") who has already made up their mind. And that works both ways; I'll go out on a limb and note that AFAIK I have never said "all amplifiers sound alike" but have opined that the majority of SS amps driving the majority of speakers sound close enough to be considered identical for all practical purposes. Techie friends who hold the "all the same" opinion can be quickly converted by picking a speaker with a complex load impedance and then trying a few amps (always fun to throw a tube amp in the mix). I have never heard a difference with a power cord swap unless the original was defective, but that's IME/IMO. I have poo-poo'd things audio in the past that turned out to be real, measurable things that good engineering could fix. So a I remain a skeptic (and am from Missouri) but try to keep an open mind.
Even on power cords... - Don
). Disclaimer: I do not know a lot about audio power conditioners. Power electronics is not really my field.
