Power cord is a big subject in terms of sound quality. 2 power cord is very very important in HIFI. the amplifier power cord and the dac/cdp power cord.
This is because EMI/RFI can get into the source (amp and DAC) and gets amplified, limits the bandwidth, resulting in noise and congestion.
if u use tube amplifier, the effect is even greater. I have just changed my power cord to Single crystal copper (OCC) on my tube amplifier and the effect is tremendous.