At first I used a standard WyWires Silver Juice II on my Pass amp then added the HC (high current) heavier version and noticed an improvement across the board. Nelson Pass is known for saying PC don’t make a difference on his amps but I disagree. I will admit I really couldn’t hear a huge difference until I added dedicated power lines which after doing so I realized my amp really opened up and that before it did sound a little lean. Still using WyWires and really like their cables. I’ve recently added a Platinum HC series to my Pass and again a noticeable improvement, more air and lower noise floor. If you don’t have dedicated lines then you might not hear much of a difference as some suggest.
I will add if you stick with the stock cords, in my opinion the receptacle outlet is maybe the place to start. If you’re a little handy keep the cable and cut the plugs off and buy some Furutech plugs from VH Audio. I feel the plugs are as important if not more than the actual cable. If you don’t feel confident doing this yourself, I’m sure you know of someone that can assist... it’s very easy. If you’re never done this before, just do one end at a time and pay attention to what wire went to which prong/set screw.