AsherjohOPPO ha-2 se is a legendary amp/dac combo able to drive MANY headphones including the infamous fostex t50rp mk 3 known to be one of the hardest headphones to drive as its a planar magnetic headphone. The HA-2se is legendary due to the fact that its audio quality rivals some of the best desktop amp/dac combos. A big plus from me.
Zeos reviewed the oppo ha-2
https://www.youtube.com/watch?v=j5UQSqwRPQc
He was exceptionally impressed with it, and the ha-2 se is the updated version with more soundstaging.
AsherjohI have one and used it all weekend. I was using my travel Brainwavz HM5 headphones which easily can push these headphones, and yes they can push the mk 3 cans!
AsherjohYep I use the OPPO HA-2 for my H6xx, and before that my Sennheiser HD560 Ovation. I really like the combination. Very convenient is that I can connect the OPPO to my Android mobile phone (LG G3 which will be replaced very soon) and use the audio program USB Audio Player PRO to stream bit-perfect my flac files on my network to the OPPO. Super sound in a very small overall package.
AsherjohThis one actually belongs to a friend of mine. I believe it was 250ish during a sale on Amazon. My own portable unit is the TTVJ Slim which is much older. It's a great amp but the DAC is a bit dated now and it's hard to find used.
AsherjohHA-2 will work nicely, I paired it with my laptop and my mobile phones/ tablet. Only catch is you need to be up-to-date with the installed driver/ software, and one certain brand of mobile phone just refused to synchonise with the HA-2 (no dac/ data function, analog amplification is fine). I did the usual problem solving on my end, A-B it with different devices, emailed back and forth from technical support about 8 times, hard-resetting it... conclusion is "such is life". Good luck with yours.