I'll soon be picking up a beyer 990 pro and an amp/dac, so I can improve my music listening experience. I'm looking for a good amp that will work with the 990 pro, music preference and as well as my cash on hand. My music preference consists of Hip Hop (50 cent & co.) Rock (Skillet, Red, Three days Grace & Co.), Metal, R&B (Banky W and Co) and gaming (if this counts as a preference although I have a PC 350 atm and ATH M50s) and I have a budget of around $150 for the amp/dac. So far, I've been able to single out the beyer 990s as a good choice for headphones, but the hard part is getting an amp/dac combo that will bring my PC (source) back to life and since I'm completely new to this kind of stuff, I decided to ask on here so I can get a few more ideas and perspective of things.The current list of possible amps/dacs that I've been able to put together includes the tube based HIFI EF2A and HRT Music streamer II. I need help on deciding which amp to get and maybe ideas for better headphones in the 990s price range.