Schiit Lyr + Schiit Bifrost OR Burson HA-160DS for HD 650

Burson amplifier fits better to HD650, because it sounds more transparent (650 need it). Lyr has more powerful bass - I don't think it will be good for HD650, wchich already have quite powerful bass and Lyr is not as transparent as HA-160DS.

But, I think that separate Schiit DAC is better, than built-in Byrson.

If I may butt in and add another DAC/Amp combo in that price range for your consideration: the CEntrance DACmini.

I've actually been contemplating the same thing as the OP, with the addition of the DACmini of course, as a future set-up based on the HD650. So I'd also be grateful if anyone has any insight regarding the synergy of the HD650 and the Lyr+Bifrost/HA-160DS/DACmini.

the dacmini is great! it is very neutral, more so then all the other set ups. i feel that the details are also presented the best amongst the group, especially the treble, which the hd650 needs as the treble is a bit recessed.

the burson is a tad warm, and not as detailed as the dacmini. the soundstage of the burson is a bit congested and small, so i feel that it won't pair well with the hd650. however the prat and bass slam is excellent, to my ears the best amongst the group, though the lyr is not far behind. 

the lyr and bifrost is another great combo, good soundstage, excellent dynamics, but i feel the highs are not as good as the dacmini. it is also a bit warm, which may not be so good for the hd650, which is already a very warm and dark headphone.

hope this helps