Are all power cords the same?

[Gremal]

I never imagined it could make a difference until I actually compared several very different cords, including an Electra Glide Fatman (this was back around 2001), a Mapleshade cord that I believe was called DNA, a stock cord and a few others. Each one sounded considerably different--some clearly had a negative or positive impact on the overall sound. We used the cord feeding my amp, but I also noticed an effect on the disc machine.