What was the first power cable that you noticed a difference in the sound?

@drbb ,

The problem is most audiophiles have either a preconceived notion as to their choice of cable, or want to compare cables. If one buys  McIntosh gear but doesn't care for the sound of the Audioquest cable and prefers a different cable, he doesn't want to pay the unnecessary cost of the cable.

bigtwin:  you're absolutely right.  It made perfect sense to me at 2am last night but that would be with a signal passing cable and that's not what was being discussed.  Mea Culpa!

@tennisdoc56 

I tend to agree with you that there is no valid scientific explanation re: much of the wire claims.  That said:

1.  Several sub assemblies (e.g., transformers and most digital products) spit out a lot of noise that can, indeed, travel back through the mains. (Bringing up the need for isolation at the plug, which is a different topic)

2.  Quality insulation helps the noise from going somewhere unwanted.

3.  A lot of supplied power cords do skimp on copper gauge and nice fitting plugs.  Electricity and interference will take the path of least resistance.  So a low (by which I mean bigger) gauge wire provides an easier path.  I’m not opposed to the idea of a high gauge wire might be starving a component for a bit, either.

4.  Nice wires tend to be bought longer and are more flexible.  So people take more care with routing of interconnects and mains so they cross at 90 degrees and don’t run close parallel, which also helps with interference.

5.  Tight fitting plugs make a better connection.  Hence why hospitals use hospital plugs.  
 

Note nothing here discusses magic crystal wire with unicorn hair.

Just low AWG wire, with good copper, nicely insulated (say, the kind the IT guy buys for  your company router) and perhaps a secondary sheath, of generous length for proper routing, with hospital plugs.  Not cheap stuff, at all.

Different, but related, issue:  components need space and isolation.  They all generate all sorts of noise.  The interactions are so complex it might as well be voodoo.

Source:  I was an electronics countermeasures officer in the very first Gulf War hunting SCUDs in the middle of Iraq from a POS Kiawa helicopter with no weapons packed with finicky electronics.

I am also struggling with this conundrum, but I gotta side with this response from a different forum....

":

If someone is selling a product with faulty/inadequate power cables, I'm pretty sure there would be recalls and/or lawsuits.

Rather than a safety concern the scam artist's sales pitch says things along the lines of "The inadequately thick (meaning gauge) cord they gave you for free is choking your amp from receiving the full current in needs to provide you with the punch and dynamics your amp is actually capable of". See their story is the necessary cable is "Just too darn expensive for them to give you and still sell the unit at a competitive price." What they count on is that the typical consumer has no idea that thick power cords are actually a relatively trivial expense to the maker. All they see is that Monstrous Hype AC cables are expensive so that's their frame of reference.
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To the general audience now.

The notion an amplifier maker has the wherewithal to design a competent amplifier but either due to incompetence or malfeasance only supplies an inadequately thick (gauge) AC power cord to provide maximal performance with it (considering how incredibly affordable they are when bought in bulk), is laughable.

The aftermarket AC power cord industry is predominantly a scam. Sure if you lose the original cord, need a longer one (which if significant may require a bump up in gauge), or think the appearance matters because you've been told you should, fine. But the sound does not change.

THE LAST LINE SAYS IT ALL!