Any real difference in RCA cables quality for sub?

A line level cable, analog out to pre/receiver, will allow you to hear differences in conductors, shielding, and connectors. I have repurposed four fairly expensive Spdif cables at this spot, each cable had their own individual sound characteristics. I have never heard much of a difference swapping good quality cables from pre/receiver to a powered sub.

Please don’t write things like "pre/receiver" without clarification. No one should ever give the impression of a receiver being equivalent to a pre-amp. Door-stop/receiver, boat-anchor/receiver, POC/receiver, even POS/receiver, are the preferred terms.

If the power cord affects it like that this tells me the Aurender is using batteries to avoid building a more expensive power supply. But if the batteries are connected to AC then all the AC line noise can ride across the batteries same as it rides across even a very expensive power supply. Think about it. If power supplies worked perfectly power cords would not work at all.

Put it this way. I am really thorough and do an amazing number of things in the name of sound quality. The quality of the interconnect used for my subs is so critically important it is by far the cheapest and worst in my whole system. That's how much difference it makes.