@drbond Until very recently I would have agreed with your assessment of power cords making a difference. Out of morbid curiosity I picked up some very inexpensive (fairly stiff to address the OP) W Audio cables on Amazon. I have three of them in my system now, but will only say with conviction that it changed the sound of my Pathos Classic One MkIII amplifier (with 1960s Mullard tubes). I noticed the change immediately and can't imagine that any audiophile wouldn't able to also hear the difference in my system. Based on that experience, I have added Audioquest Chicago interconnects (replaced BJC LC-1) which also made a clear difference to my ears and was also immediately noticeable to me. Based on that experience, I added an Audioquest Cinnamon digital coax and I can't say that I could tell any difference between it and the BJC silver plated cable that it replaced in my system.
Do good power cords have to be stiff?
As far as I am concerned, stiff power cables are a pain in the butt. Wonder if anyone has found a great power cable that is very flexible?