Ok, here's an update.
New main rig is:
S4 (UAPP) --> self modded USB OTG micro to USB B --> iFi Nano iDSD
Second rig is:
iPod Classic 7 --> Custom Nordost LOD --> FiiO E11
And for compact living - an S4 case with an Audioquest Dragonfly dual-locked to it, and a home made slim USB OTG cable.
Headphones are Focal Spirit Classic with Supra 3,5 mm exchange cable.