New expensive power cord for amp and no change in sound?

I have found that some components, especially amps, respond to power cord changes much more than others. The same power cord might perform beautifully on one amp and make no discernible difference on another. I'm not sure I would have believed that had I not experienced it myself. 

I switched out my upgraded PC from stock that were Shunyata King Cobra  (2) last summer for the Audio quest Dragon HC (2) and I’ll tell u I could hear a big difference. More clarity. Bigger soundstage. More details with voices and instruments especially the plucking of guitar strings. Well worth the upgrade. Btw. Amps are ARC Ref 750s. 

Sounds like you’re $500 cord worked great with the Pass. Sorry you had to learn/ relearn that synergy, not price are more important and always listen to cables with a return policy.

@roxy1927

Since you mentioned Shunyata.. I believe that they have power systems which consists of power cables and a conditioner. I really never had much of an expectation of replacing one power cable at a time and noticing a difference, so I took the system approach of purchasing seven power cables and a conditioner with the ability to return everything. In short, I decided to keep the Shunyata products and beg for my next meal. Attention to power has made the biggest improvement to my system, which now runs off a 300ah battery.

There you have it.

"I bought into the never ending advertising but people had positive things to say..."