Is it all in my head??

Welcome to audio! Where you generally first have to hear a given difference or effect for yourself...and then struggle to find the evidence or proof of its existence after the fact.

That’s because there is actually a lot about this hobby that technically seems to ’defy’ common sense. There’s at least one old hobby saying that seems to hold up that goes: "never judge an audio book by its cover"...which means just because an amp is ss, doesn’t mean it will always sound bad, or just because a pre-amp is passive, doesn’t mean it will always sound good, and so on.

People I think make the mistake of trying to grasp the hobby as a set of "rules" that must be learned. After a few decades at it, I no longer think that even applies. For most every rule someone comes up with, there may be anywhere from one to a dozen different exceptions to it...IME, they’re there, you may have to look for them a while to find them, but they’re there. I myself happen to think of this hobby as having far more exceptions than rules, no matter what others may say.

The only thing worse than hearing a difference and not being able to explain it is to insist that the difference cannot possibly exist because it just doesn’t make sense, without having heard it.

5@ivan_nosnibor   I have no quantitative reason for what I hear and I only bought this cable because it looks cool and it would have cost me >50% of the price in parts to build it myself and i cant fabricate my own connectors.  Also, I build most of my own cables from the same wire and it seems like the way I twist, braid or wind it impacts the sound (not always for the better, which contradicts my oxidation theory)...

An ee told me once (and I’m not nearly an ee) that sound was primarily determined by power-vs-length-vs-geometry. Other things like noise cancellation or group delay caused by insulation thickness and material also enter into it. The actual calculations for that sort of thing are often proprietary and not given up easily by those in the know. But, this tends to mean that different components that have different power draws tend to require different power-vs-length-vs-geometry solutions But, the rest of us have to struggle along when it comes to DIY...or copy what we see that works for a given app, or whatever.

I've built speaker cables and IC's, but have never attempted power cords.

my speaker cables vary wildly with geometry... i use the same 12-awg cable for all of them.. i've built about 4 pair so far for critical listening.