Grado cables are midrange-rich and the Black Dragon seems to be high-bass heavy with recessed treble. If you take a midrange-recessed silver cable, there will be deep U equalization perceived on the PS1000 IMHO. There are better options to make the PS1000 or the HD800 sound better than replacing the cable. My humble experience says that all those improvements reported here where due to aftermarket cables masking some imperfections of the signal chain.
If I had to try another cable for PS1000, I would look for pure copper because of overall slight midrange emphasis and treble roll off in such cables. Silver plated copper is IMHO the most transparent variant and pure silver is something that I would never use alone. You can mix silver and copper wires to build a decent cable but using silver only can result in some kind of tonal incompleteness. The bass will be hard but a bit rounded, the midrange rather dark and huge soundstage partly due to prominent trebles.
Edited by majkel - 7/14/12 at 6:50am