If the person buys (spends money) on a power regenerator and then needs to buy a new power cord for it to sound better,On paper, but there is no such thing as 100% isolation. They are all connected in there. Also there is no such thing as "power signal" and "music signal". They are all the same since you modulate the power to get musical signal, so in that respect, the musical signal comes straight from the power signal. A quick look of the power amplifier schematic will show this.
It's like noise insulator. Regardless how much you put in, there will be some noise that leaked through.