I must admit I'm not very familiar with the HD 650 aftermarket cables, all I have ever used are the stock cable and the Equinox that I just received today. What I can tell you is that with only 2 hours of burn in, the performance of the Equinox is in every aspect much, much better than the stock cable, which isn't bad in itself. The soundstage of the Equinox is very wide compared to the stock cable coming out of my Waveterminal U24, and I am expecting to get my modded MPX3 later this week and I can't even imagine what that will sound like. I highly, highly recommend this cable, it is really incredible and I can't imagine any aftermarket cables sounding better than this- the only big downside (and a relatively big one at that) is that the wait time is looong, about 18-20 weeks. I ordered mine last spring and I just finally received it today. I can tell you though, it was worth the wait.