PIFI DAC expansion board (PiFi DAC +) is dedicated for Raspberry Pi 2/3/B +, which features TI's higher-end DAC chip (PCM5122), I2S interface(non-USB interface). It supports volume adjust by hardware (the old DAC uses PCM5102A chip hardware, which can not support volume adjustment by hardware). With this extension board, users can use it with audio playback system (eg: volumio, xbmc system, etc.) to build their own network HIFI player; It provides two kinds of output interfaces, making it easier to connect external amplifiers. Now you can get rid of high PC power consumption, slow start and slow shutdown, big power supply noise.