What difference do power cables make?

@thyname Thanks for your history with Pangea. I will definitely circle back to power cords again, and I appreciate your recommendations. Saving for future use. 

If your equipment isn't grounded and your interconnects have poor shielding then you certainly need the best shielded power cables you can find.

You'd be better off grounding all equipment first. An RF Router Plug-in from Russ Andrews with separate grounding cables from each case back to the router should be your first consideration.

Double shielded interconnects are highly desirable.

If you still have RFI (Radio Frequency Interference) then go with shielded power cables.

“Do you feel that it was worth the additional investment?”

On Power amplifiers especially.  

Love this power cord for dummy’s stuff again and again. Especially the you have to train your ears and know your system to hear a difference BS, that equates to no one else can hear it so it doesn’t exist…dah. Good equipment isolated wiring proper gauging if necessary power conditioner. No tripping down the yellow brick road to a snake oil pit, education common sense science…Walla !!

@dayglow Your experience of different outcomes when improving the input AC speaks to what someone else said about the internal power supply of the end component being more important to the equation than the power cord, et al. Any cord or cable is a purely passive device so it can only take away (filter). A well designed power supply is designed to filter, so pre-filtering might or might not have an audible affect (imo). I'm not pointing the finger at you, I just picked your response because you mentioned different end component experiences with the same source.