I just bought a AKG K240 MK II, and am loving the sound produced by my Macbook Pro so far. However, on my iPhone I can only hear stuff at 2/3 volume or above. Below that there's nothing. Also the bass seems to be missing the kick that I've been reading about with these headphones. I assume they will get better with greater usage so that they have time to burn in.
However, I need a portable amp so that I can use these with my iPhone. I've read about the FiiO E5, and this is my top choice at the moment, but I would like some other options to look at as well as any other recommendations.