The Crystal does nicely split the difference between the M2 and RE-400 in bass. Sounds like it would be a good fit for you. I don't think I've tried a single new portable amp this year so I'm not exactly up to date . I just use a HiFiMan HM-901 when I'm not too lazy to carry it around, and the Cowon J3 or my Nexus 5 straight when I am.
11/5/14 at 7:18pm