A list of stock Android-powered devices reportedly interworking with standard USB DAC:
stock Android device > digital USB audio out >> standard USB DAC >> amp >> headphones
http://goo.gl/BOnMDQ
A list of standard USB DAC reportedly interworking with the Android-powered smartphone Samsung Galaxy S3:
stock Samsung Galaxy S3 > digital USB audio out >> USB OTG cable (ID pin grounded) >> standard USB DAC >> amp >> headphones
http://goo.gl/2fPYtk
A list of standard USB DAC reportedly interworking with the Android-powered smartphone Samsung Galaxy Note2:
stock Galaxy Note2 > digital USB audio out >> USB OTG cable (ID pin grounded) >> standard USB DAC >> amp >> headphones
http://goo.gl/4Nq4Y8
A list of standard USB DAC reportedly interworking with the Android-powered smartphone Samung Galaxy S4:
stock Samsung Galaxy S4 > digital USB audio out >> USB OTG cable (ID pin grounded) >> standard USB DAC >> amp >> headphones
http://goo.gl/dIwrqp
A list of standard USB DAC reportedly interworking with the Android-powered smartphone Samsung Galaxy Note3:
stock Samsung Galaxy Note3 > digital USB audio out >> USB OTG cable (ID pin grounded) >> standard USB DAC >> amp >> headphones
http://goo.gl/7Bvkhz
A list of standard USB DAC reportedly non-interworking with the Android-powered smartphone Samsung Galaxy S3 / Note2 / S4 / Note3 using USB Audio Recorder PRO / USB Audio Player PRO:
http://goo.gl/kHJmfE
A list of USB OTG cables:
http://goo.gl/4JyOe5
FAQ:
http://goo.gl/A4dCnP
The basics:
http://goo.gl/MCFY2x