How power influences the sound depends upon the equipment: The power supply in an amplifier could do so thorough a job of filtering out noise along with hum that it might make power conditioning irrelevant. If you use single ended triode amplification it will always draw the same current rather than demand more current for loud passages in a recording and the resistance of a less expensive power cord will be trivial. Higher audio frequencies are easier to filter out than 60 Hz hum and many vacuum tubes have cutoff frequencies at higher radio frequencies.
Watch out for the placebo effect for cables in general. There is some junk science used to market audio.
Watch out for the placebo effect for cables in general. There is some junk science used to market audio.