^ this ^
Cool, thanks a lot for the link.
My impression on ODAC comes from here http://www.jdslabs.com/products/46/standalone-odac/
So there are indeed different versions.
The O2 is open source, you could build it yourself. There are kits available for just that purpose. My pair were built by Walter at head'n'hifi. I have the ODAC XL paired with the O2 Desktop Version. Basically more connection options & mainly on the rear panel. The O2 has both RCA in's & out's.
Honestly, they sound fantastic!