I had posted earlier that "I bought some of the Xangsane P-6008Ag power cords. Burned them in for days before listening to. Sounded terrible."
However, as I had some other PC's to burn in, I burned the Xangsane P-6008Ag another week (about 264 hours total). At that point, they sounded great.
So, if you are going to by Xangsane stuff, plan on burning in ~300 hours. I read something similar on their USB cables.