Well, I've been living with the E18 a little over a week now. Source is a US Samsung g3s, flac files ripped from CDs, power amp player, USB OTG to E18, hi fi man re400s. I believe it is a first gen E18. No problems were noted in using the USB OTG cable! Regrettably, I can not say I am super impressed with the E18. I have about 50 hrs on it and compared with the straight phone jack it is quite veiled over the upper registers. It may need more time to find its voice but that is how it sounds now. More troubling is the problem I am having with the bass boost at low volumes. At vol 3 or less a high pitched tone is generated along with the bass boost. I have written Fiio but have not received a reply. Finally, you should note the size precludes the use of the camera when strapped up. I had not thought about it until I set it up for use. If things change or I hear back from Fiio, I will write it up.