I wouldn't pair this with the K7XX's but it actually works well with the HD6XX's. On the AKG's it's too bright for me and it takes away some of the soundstage. It is slightly clearer than the dacport (killer starter dac/amp) or xduoo xd-05 (pure junk) but the highs kill it. That's where the HD6XX's are great because of their veiled highs. This amp is not quite powerful enough to push them really high on those quiet songs but does alright on the rest. I'd still say skip this and go with a tube amp like the Valhalla 2, what a great pairing. If you did any of the mods to your HD's skip this dac/amp, or any sabre based dac, as those mods bring out the highs too much. Go with a darker dac like an akm44**. Good luck and have fun listening!
salander1800It's just ok. Driver installation was harder than it needed to be, the huge V sound signature killed my K7XX's and it just doesn't sound as good as other amps that are in its price range. If I had a pair of HD 590's with huge mids this amp would be good, it would bring the sound back down to even. But it just isnt good for the headphones and sound signature I like. That's what I have against it. If it were 50 bucks I wouldn't complain.
JHum22Everything is ok when you have no problems with your unit. Then you try to get warranty service and you find out you are on your own. There is no warren with XDU00. Good luck... This message is for JHum22. All it takes is one time time to get burnt. Then you stay away.