It's a nice outfit, very minimalist. In fact you had me trawling the net for most of yesterday evening try to find something similar I could use.
Nearly any DAC-Amp I think would work, but of course check the Android USB OTG thread here - DanBa updates every five pages (page numbers ending in 0 and 5) with a table or the link to a Google doc with the table. Of course, if you can land a Cantate or better yet the Symphony or Opera, that'll rock (same amp but better DAC, I think). Shanling I thnk has one that has USB inputs dedicated to iDevices and Androids (probably the same port for PC and Android).
I've been meaning to get a DAC for this set up too but I need to maintain its streamlined form factor. That means the DAC should be small enough that I can put the dock on it and it won't be that much wider, or the dock has a 'straight' form factor (digital inputs on one end, analogue outputs on the other end) that I can hide behind and between these two. I considered CDPs, but not only were they more expensive, some were really screwing up the sound. I just need to find the right cable to get the USB signal into the Schiit Modi that will have the appropriate splitter where I can hook up a battery charger that it will use as a power supply. The ODAC supposedly works with the S3, but I'd really much rather have a separate battery pack or PSU (or otherwise not use teh phone's USB power) to power the USB receiver, the DAC chip, and the analogue output stage. That and other expenses are getting in way right now.
You say you're using OTG USB - where did you get either the dock or long cable or both to do this? The only docks I can find only allow a 3.5mm output.
I looked for one that basically works like an iPod dock. Search for "sync dock (insert phone or tablet here)" on Amazon, and check that it has a microUSB port on the back. If it's not an Android-specific DAC, you'll need a USB On The Go adapter for it (you can get these from Amazon sellers too). I just picked the RND dock because it was white; I also picked up a Superleggera two-layer case, since the inner rubber case allows for frequent removal of the case without the plastic outer case scratching (as the plastic-only case on my original SGS did). Not a fan of using just a rubber or silicone case because from experience if dropped the phone tends to pops out of it after the first impact.
I actually just gambled on the dock and OTG adapter working as such, but before this I already gambled on using the iPad2 dock with the camera connection kit's USB adapter so I can also have it upright next to the amp/DAC.