You won't need the app to use FaunaI have the usound amp for a desktop / tuning solution, but planning to use the guts from some Fauna audio glasses for wireless and see how that sounds. I may need to revive an old cell phone to get access to a functioning Fauna app, haven't quite gotten that far yet. Finding a case and a battery for the usound amp would require big pockets to carry around, but is possible.
The Fauna glasses use a TI LM48580 amplifier, you can easily get a dev board of that one.
Though there are more performant solutions (less distortion, more stable DC supply) now, like USound's UC-P3010 amplifier. XMEMS also have an amplifier (Aptos) that can be used very similarily (with very similar performance too)
(sorry for the somewhat necropost)