@1235 it should work if every software/hardware USB audio-required component is functional.
Android USB audio
FAQ
http://www.head-fi.org/t/595071/android-phones-and-usb-dacs
I have an Android device, a USB DAC and a USB Type-C cable which are reportedly compatible, but I have not been able to make it work. Is there a trick to make it work?
Nexus 6P is reportedly compatible with a standard USB DAC (i.e. the USB host driver of the Nexus 6P can work with the ODAC).
http://www.head-fi.org/t/595071/android-phones-and-usb-dacs
The Google USB Type-C to USB Standard-A Adapter is reportedly working with a standard USB DAC like the ODAC and a dual-role Android device like the Nexus 6P.
http://www.head-fi.org/t/595071/android-phones-and-usb-dacs
I have an ODAC.
My ODAC is compatible with the following different third-party USB audio soft drivers: UAPP, HibyMusic, Onkyo HF Player, Neutron (i.e. UAPP, HibyMusic, Onkyo HF Player or Neutron running on a Nexus 6P, an Android device with a fully functional USB host driver, can work with an ODAC).
And I just found that the ODAC is no more compatible with the native USB audio of the current version of Android running on my Samsung Galaxy Note3. A few weeks ago, at the upgrade to Android 5.0, it worked!
It is not a problem for me, because I listen to music using the third-party USB audio music player UAPP, the best sound music playback software to my ears.
1st question: What (native USB audio or third-party USB audio) music player did you use?
If the native USB audio does not work then you need to use one of the third-party USB audio music players which include their own USB audio function / soft driver compatible with the ODAC.
Some component of the setup is malfunctioning.
Each component should be separately tested: Go to next test only if the ongoing test is successful. A reset of the Android device is recommended before testing.
2nd question: Did you reset your Android device?
. Test the USB DAC with a PC or a Mac:
PC >> regular USB cable provided by the USB DAC maker >> USB DAC >> amp >> headphones
I suppose you have tested your ODAC with a PC / Mac.
. Test the Android device and a USB Type-C adapter with a simpler USB peripheral like a USB mouse or a USB keyboard:
3rd question: Did you test your Android device and your USB Type-C adapter with a simpler USB peripheral?
Android device >> USB Type-C plug to USB Standard-A receptacle adapter >> USB mouse
. Test the setup using the USB Type-C adapter:
Android device >> USB Type-C plug to USB Standard-A receptacle adapter + regular USB cable >> USB DAC >> amp >> headphones
If the tests are successful, apparently the USB Type-C cable is not functional (i.e. CC pin of the USB Type-C plug not connected to GND through a resistor Rd (5.1 kΩ)), then fix the USB Type-C cable or buy a new one.
Android device >> USB Type-C plug to USB Micro-B / Mini-B / Standard-B plug cable >> USB DAC >> amp >> headphones
"Important: connect your device BEFORE starting the app, otherwise it will not get detected! When you connected your device before starting the app and it gave you a 'failed to initialize or open the USB device' message or similar."
http://www.extreamsd.com/index.php/2015-07-22-12-01-14/usb-audio-driver