Portable Amp Recommendations?

So... since I've moved away from home to college, I don't stay in my room that often to appreciate my yamaha hs50ms, that's why I've come to you guys today asking this question. Is there a portable amp that y'all would recommend since most of my time now is in the library or spent outside my dorm, what I'm using as my audio setup are just my ipod classic (7th generation) and Sennheiser HD 25-II. Thanks!





It all depends on what you want to spend i have tried the FiiO E11 It has a built in re chargeable battery too.