Setup: Xonar Essence STX(stereo output to 3.5mm) > HD600.
Just got HD650, and from my comparison testing thus far, it sounds fairly recessed/dark/uneven, with more detail/clarity, smoother treble, and more-yet-muddy/fatiguing/'cheap' bass(very disappointing). Only the treble/vocals sounds better to me than the HD600. So, these will very likely be sent off to Ebay, unless there's some fix I'm missing. They are used, so I'd imagine they have been worn in, but they are quite clean...
When I put the HD600 back on, everything sounds right again. <3 Except for slightly bright treble(and a bit less detail/clarity). Would an O2+ODAC / Magni+Modi make any difference? Or do I need to take a significant leap up, and get an Asgard 2+(something) / Essence One / NFB-12 / etc?
Thanks!