When I did some research as to how AC regenerators work I came to conclusion that AC power cords do make a diff + I actually do have a good power cord connected to my PS300.One possible explanation that comes to mind would be that the shielding of an upgraded cord would prevent rfi or other high frequency garbage which may be produced by the regenerator's power supply from escaping and coupling from the power cord to other points in the system. Similar to one of the major reasons that a shielded power cord can be beneficial on a power amplifier.
Best regards,
-- Al