I use oppo pm1 with mojo now. I would try beyer dt880 600 ohm a true budget high end piece of german engineering. The mojo drives them so beautifully and effortlessly. The 600 ohm version is tuned for dedicated gear/amps and multiple reports indicate the SQ is better than the 250 ohm versions which are aimed at hi-fi stereos. Don't worry if you start to see the the white ball on mojo at high volumes with the dt880 as mojo handles 600 ohm loads if need be. I even used the beyers with great results on H2 when i had it.