Power cord heiarchy

Schipo, the designs always have tradeoffs and conditions in the design facilities may differ than the ones at home. Good manufacturers generally address that but i know of more than one amazing sounding amps that do benefit from power conditioning, better current etc. That is quite clear and not a psychoacoustic phenomenon. Now, extending that argument to power cords is a bit more artistic as the science is not yet conclusive. nordost recently made some efforts to prove their point and I am not well versed enough with electrical theory and practice to be able to fully comprehend what they are saying. That in itself may be an issue.
In any event, imho power cords do make a difference and one that is often not subtle. In my system and my conditions, I find that they make a bigger difference than even interconnects.

no human can hear much past 20 KHz. Few microphones respond to frequencies beyond that, and even fewer loudspeakers can reproduce that high.And your telling me that you can hear the small difference in power cords. Every competent circuit designer knows how to filter out power line noise, and such protection is routinely added to all commercial audio products. Spending hundreds of dollars on a six-foot replacement power cord ignores the other hundred-odd feet of regular wire between the wall outlet and power pole.