I have the Cardas cord and the difference is striking. There is improvement across the entire spectrum. However, my personal taste is for a bit less high end (to me it's brightness to others it's detail). I've therefore relegated them to a pair of HD545s (they seem to fit fine) that need high end extension. I've just ordered the Equinox replacement cable from Stefen Audio Art that has been described as having essentially the same benefits as the Cardas but with a 'warmer, more polite presentation.' Unfortunately, I won't be receiving the Equinox for about a month due to their backlog.
You can find a detailed comparison that I found useful of the Clou, Stefen AudioArt, and Cardas replacement cables at:
www.head-fi.org/forums/showthread.php?s=adb45146e8a5219c1667cbae97b73933&threadid=10395
You can find a detailed comparison that I found useful of the Clou, Stefen AudioArt, and Cardas replacement cables at:
www.head-fi.org/forums/showthread.php?s=adb45146e8a5219c1667cbae97b73933&threadid=10395