Here is a site that has some testimonies as to their effectivness: (http://www.canuckaudiomart.com/forum/viewtopic.php?t=1782) As usual there are those that haven't tried them, and have an opinion(for what that's worth=0). I would add to the previous post: If you have upgraded your power cords, and not heard a difference: Don't bother. Some systems/rooms won't resolve the differences, and some can't hear the differences(or: won't admit there is one, 'cause they can't stand being wrong). I'm glad you posted this. I'd forgotten I wanted to get a pair to try in my Carys(a year ago).