The power cord thing is confusing. I just installed a set of DIY power cords on my power conditioner, amp, preamp and D/A. The cords use
CryoParts CryroMax3 cable and low-end Furutech connectors. Parts costs is about $150/each which roughly equates to a $500-600 production cable. Each cable also has a
Versalabs Red Roller at the IEC end. These cables were a switch from the Discovery Cable power cord, an entry level type product.
I initially installed a single cable feeding the PS Audio P600 power regenerator. The effect was subtle, but positive enough to make me want to go further. I then installed them on all the electronics listed above. The audio effect was definitely less subtle than adding the single cable, but still subtle. That said, I think the power cord switch was the best $600 I've ever spent on the system. The overall effect is totally positive, an improvement in all sonic areas.
But this is where the confusion comes in. I don't know what actually causes the sonic changes I hear. Is it the power cord? Is it the cord's Furutech connectors? The Red Rollers? Could it simply be the physically tighter connection the Furutechs make as opposed to the purity of the copper and polished gold plating? Maybe it's the way I positioned the cables differently due to different flexibility. Might it have nothing to do with the power cords themselves, but simply plugging them in and out several times removed a layer of oxide on the connectors. I could go on further, but I think I've made my point. Even inserting a device as simple as a power cord, and they are simple devices, introduces a relatively large number of variables to be considered.
Then you could also add price/value to the equation. I only spent $600 for the whole system. If I had spent $2,000+ would I hear differently? Or might be I have it backwards and it's the fact that I think I've scored a bargained is influencing my hearing? Like I said, it's confusing.