XP-1 is the first USB DAC which was developed for Android 4.0 or above.  Also, the USB DAC could be used for PC without having to drive.  DAC uses two parallel WM8740, and a built-in OP+BUF architecture, OCL (output capacitor-less) with split power supply, ultra-low distortion, low noise, high slew-rate for analog signal.  The device improves the sound quality immediately.