By the way, how does pb1 / pb2 compare w/ headroom micro amp : http://www.headphone.com/headphone-amps/amplifiers/headroom-micro-amp.php   *Edit*  OH i see.  the pb2 is portable w/ a battery source   Now I'm wondering if I should pair the pb1/pb2 with hd598 instead

sweet, thanks!  PB2 would be a pretty solid choice for the HD650's?  It should cost around $325, which is 3x the price of the FiiO E7. Does it sound much better than the FiiO E7?  I'm really not familiar with amps

@ProtegeManiac: Oh I see.  Where would you buy these amps?  I've always been wondering why Amazon only offers FiiO, but nothing else

Oh, I'm looking for a pair to carry around from place to place, not necessarily for listening in public.  Open-air shouldn't be a problem if I'm using it in a fairly quiet environment. I want a good pair of headphones that I can use at home and at school, but I also don't want to carry a huge...

Recently, I bought an Audio Technica ATH-M50 and I didn't like the sound quality of it.  The trebles were too piercing for my tastes, the recessed mids bothered me, and the bass was a bit over kill.  They were also not comfortable to wear for extended periods of time.  I eventually returned...