I recently bought a pair of Monster turbines, and already own XB500's. I plan on soon buying a pair of ultrasone pro 550's, and I have quite a bit of extra money laying around since christmas and my birthday just passed, and I just sold my Bose AE2's. I am looking at buying an amp (used 95% at home, probably will take on airplane and car trips) and don't know what I want. I am definitely looking for something under $100, and want it to tighten up my bass a little bit and just provide me with a better overall sound. I especially want some added bass on the pro 550's because I doubt they will have as much as I am used to.
Honestly I know nothing about amps so I have probably made a few mistakes already.
I will run it straight from my cell phone most of the time, it will probably see some use with a Nexus 7 and Inspiron 15r as well.
Currently I'm eyeing a FiiO E11, ibasso d-zero, and a digizoid ZO2. I would buy the last 2 used as they are a little over my budget which is about $100 in amazon credit.