I am a big believer in providing an adequate power cable. I've seen a 14 lb, 8 wpc Sophia Baby tube amp suffereing from inadequate power cable using a generic 14 awg cable. I slapped a generic 10 awg cable on it and it bloomed.
But cables aren't tuners. I've often pointed out how clueless this forum is about electricity and when you don't understand something, it is easy to imagine that there is a lot more to it than there is. All a power cable can do is provide a good supply of adequate power to your amp. It has to be oversized to account for short, high power demands that support great bass and dynamics. That is all. It isn't an active component. It doesn't add anything. You have to make sure that it doesn't TAKE ANYTHING AWAY. That is all. To do that, you need a good qualitiy 10 awg power cable.
A quality supplier of 10 awg power cables is Ice Age Audio in Michigan where you can get a good cable for $100. I have no affiliation with them other than I was looking for a bit more quality than you get on Amazon....as an aside, I saw the same plugs that are used on $39 Amazon cables on an $800 power cable the other day. Think about that before you spend big money on power cables...they are not tuners.
Jerry