Power cord heiarchy

I would have thought that the design of any highend amp with their sophisticated power supplies would not be in need of a power cord upgrade.You would think that an amp going for thousands would already have an upgraded cord, or if it needed one would not the designer after listening to it included into the amps price. I mean what are we talking about penny copper no more then 6' with upgraded hospital grade connectors at both ends. I am sure if needed it would have been part of the DESIGN and included in the whole package.

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.