hieu.nguyenI have a Note 3 and the e18 already, and my phone has no problem connecting the USB DAC as long as you use the stock Sammy music player or USB audio player pro (I think it's about $10 on the play store). I *think* Neutron also works with USB audio. Anyone else feel free to correct me if I'm wrong! Poweramp does NOT work, but even so I found other players blow it away in SQ, regardless of amp or DAC.
Kudos to Fiio for including a couple of the OTG cables so you don't have to buy one before being able to use the e18 as a DAC for your phone.
hieu.nguyenI too have the Note 3 and it works just fine with the E18. I use Vanilla Music (free app) to play FLAC files, and it works just fine. The phone is bigger than the FiiO when you bind them together with the provided elastic bands, but that's not a problem.