Why not?

As a scientist I can understand that if one shows something happening on a DC supply then I know that the cord changed things.

@holmz Ah, I see.  You don’t trust your own ears.  Got it.  You and @ghdprentice would have an interesting conversation as two scientists with polar opposite views on cables.  Why not just try an aftermarket PC just to see/hear for yourself?  What are you afraid of — that your comfortable and convenient world of theories and measurements might implode if your ears tell you they’re hearing actual improvements?   Or maybe you won’t find any improvements or maybe even decreased performance.  Either way, that’s called learning — a concept I’d think a scientist would embrace.  

Why not just try an aftermarket PC just to see/hear for yourself?

@soix : it's not going to work. They will never try anything for themselves. Trust me, I have attempted to do this several times over the years. I have even offered to send them for free power cords / cables, nothing fancy, basic good quality stuff at about $100 - $200 range. They have always refused. It is a "thing" for them. They will never try out of principle. I have given up attempting to help them. I already know the story the moment I see their very first post. It is an exercise in futility, no matter what.

@soix and @holmz  Funny story about that. A friend lent me a pair of MIT Terminator2 speaker cables. I put them in my system, replacing some Crutchfield generic cables, and was amazed! Clarity, texture! I was so smitten I bought a pair of MIT Terminator2 interconnects just to see if what I was hearing could be further enhanced. Sure enough, better still. Enjoyed them for a couple of months, reveling in what I was hearing. Time came to give them back, which I really was sad to do. Determined i would have to get a set of my own. Replaced them with the old cable. Everything still sounded good. I could not find fault with the system.

Possible conclusions;

1. I am a hopeless audiophile wannabe who should be banned from any audio show room hencewith.

2. The MIT cables magically transformed my system when I installed them and somehow left their goodness there even after they were removed.

3. My expectation of how good I expected those MITs to be clouded my judgement and dimmed by auditory memory sufficiently that I could fool myself.

4. The MIT cables did change the sound and I heard that and thought it was "better", but the change back to the original was not as drastic as I had expected and I discovered I liked that "flavor" just as much as the MITs.

@big_greg Wrote:

My Ampzilla amps come with a custom power cord that the manufacturer thinks is the perfect match. It’s hardwired into the amplifier. Love it or leave it

My Crown Studio Reference One Amp comes with a custom permanently attached power cord that is 10AWG with a 30 amp plug that is cold welded into the amplifier by the manufacturer so you cannot remove it. They also give you a Pass & Seymour 125 volt 30 amp wall plug in the box when you buy the amp new and they recommend a licensed electrician to install a minimum125V 30A dedicated circuit, just for the Crown amp. Crown does not offer an aftermarket quality AC power cable for this amp but they do give you a permanently attached, properly designed and most importantly, a well implemented AC power cable to perfectly match this amp. See image #2 power cord:

https://reverb.com/item/21627144-crown-studio-reference-1-one-industry-standard-amp-power-amplifier-good-c