FLTWS
Headphoneus Supremus
I was always under the impression that a good (as in properly designed for the device in use) power supply in a component's sole purpose was to maintain a steady (DC?) voltage to the circuitry it feeds regardless of the incoming AC value within the limits spec'd by the designer (say input voltage between 110 to 130). If that internal voltage stays stable not sure why there would be any audible effect.