power cables where do I start?

The gall of the cable swindlers has no limit!

I believe everyone is entitled to their own opinion but roberjerman didn't answer your question, instead, he opened a can of worms.

If one can’t hear the difference between several upgraded power cords and/or a stock power cord then I believe one of several factors come into play here.
Equipment isn’t up to the task to produce the differences in music.
Your ears are not trained to pick up the finer detail.
You have a hearing deficit and don’t realize it.
I would always recommend that if a stock power cord can be easily replaced, eventually do it when you have the cash. Many stores will allow an additional trial period so you can decied for yourself.

@mswobo if you have not read these two forums you might find it interesting: https://forum.audiogon.com/discussions/cerious-technologies-new-graphene-cables

https://forum.audiogon.com/discussions/new-cerious-technologies-upgrade-graphene-matrix-cables

Might consider Audio Art power cables, have made noticeable "positive" SQ differences in both of my full rig systems 

+1 for Audio Art

Also consider Triode Wire Labs.

Power cords will make a difference. Best of luck.