Amp/DAC for Ultrasone 900

Best synergy I've heard to date is with Ibasso D12 and/or D6. I've tried the Audio-gd NFB-12, Nuforce Icon HDP, and now the Centrance DACmini, and I am still trying to get the sound I got from them out of the D6 and the D12. Both of them get rid of the mid-bass hump on the Pro900's, while retaining the awesome bass extension, bringing out the best out of the Pro900's. Tight, deep bass Sound staging is really good too. That's to my ears at least. 

Only with the Pro900's! My K702's sound A LOT better out of the DACmini haha. The Pro900's aren't hard to drive, I just think it's the sound signature of the iBasso's that, to my ears, made them sounds purfect. Tons of bass extension, very good instrument separation and staging, and no mid-bass boominess. Loved that combo for Dubstep or anything else Electronic. I regret selling the D12, and am considering purchasing another one.  

I took out the 10 ohm diodes of my ultrasone pro 900 a long time ago, giving it a more hollow or airy sound, but it reduced the bass boost, allowing bass to sound more realistic and detailed, more in line with mids and highs. If you don't remove the diodes, just requires a little soldering, then I'd suggest dac and amp that have a bit of recessed bass if you want a more balanced freq response. A flat dac and amp with detailed bass with normal pro 900 will have fun boosted bass which you may not like if you're after a more neutral/monitor sound.

I have the iBasso D6 and the Pro 900 and I am liking it quite a lot. I prefer it over the NuForce HDP. The synergy is very good.

Check the new Matrix M-Stage with the build in Usb Dac..

I have the older version which is only an amp and it works like charm with the Pro's..

A very transparent amp with lots of power...

I can't comment on the Dac though cause they launched recently but i think it has a descent Dac chip..

I also use it as a pre for my KRK's...