I made it work. Unfortunatly only with an external power source, so y-cable is still needed. The charger unit of the fiio e18 does not help.

Hey guys,   after reading only for a long time i finally decided to write also. Now I'm sitting in front of a Nexus 4 + Fiio e18 + DT 880 combo and still don't have a clue how to get this working. I already installed the Franco kernel. Do I need the special cable with an external battery or...