Hi, everyone! I am considering buying the DT990 Pro 250 ohm headphones. I currently have Beats Studio 2s and am looking for an upgrade for music production, DJing, gaming, editing, etc. The one thing that I am not sure on is what amp to get, as I have heard that these are fairly hard to drive. I am wanting to spend as little as possible on an amp, but I still want it to be satisfactory to power these cans. Anything in the $50 or less price range would be great. A few that I have been looking at are the Fiio A1, the Fiio A3, and the Fiio E10K (but the last one is a bit out of my price range unless I get it used). The devices on which I will be using these headphones are as follows: MacBook Air Laptop, iMac desktop, PlayStation 4 (plugged into the 1/8'' port on the controller), iPad, iPhone, and my DJ controller. I don't know if the type of music that I listen to will be relevant, but I listen mostly to hip-hop (this is very important as I also make it), dubstep, classical (especially piano solos such as Chopin, Mozart, and Beethoven), and Jazz. The amp should be portable, as I'm going to bring it places, not just on my desk. Thanks!