I recently purchased a used pair of Sennheiser 650s from E-bay. I blogged about them recently, so check it out. I originally powered them through a little mixer and it actually did really well.
I’m now powering the headphones from a designated amp/DAC from 02. It makes a nice compact desktop setup. Overall, they’re a little better than my mixer, but only by a tiny bit. They sound even better when you turn up the volume, but since I’m at work with open headphones, I have to go easy.
I would say, if you have a mixer like mine, you may not need to power it much more unless you listen to your music really loud. The 02 is a nice design, however, my only complaint is that the power input is in the front. I think this is a really poor design decision.
Other than that, it’s a nice setup. Next thing up, a headphone stand. Right now looking at a couple options. Anyone have any recommendations?