Bundle 1 Bundle 1 does not have USB input function. Bundle 2 Using PCM2706 USB subcard. PCM2706 USB is stable and mature. Not using HOST power supply method, the power supply is stabilized to improve stability. An active crystal oscillator provides a stable clock. SPDIF output level waveform shaping. Support frequency: 44.1K, 48K Bit width: 16 bits. Bundle 3 Using CM6631 24Bit 192K USB asynchronous subcard. Product Details: Use two transformers to supply power. Digital part and analog part of the independent power supply, the sound more clean. Using 16PCS TDA1543 decoder chip Parallel connection. Using PCM2706 or CM6631 USB subcard. (Bundle 1 does not have USB) Using aluminum chassis. Active crystal provides a stable clock. SPDIF output level waveform shaping. Specifications: Digital input: coaxial, fiber, USB Analog output: RCA analog output. Digital input bit rate: 44.1K -96K. Analog output level: 3.2Vrms. Power supply: AC110V or AC220V. (Optional) PCM2706 USB support frequency: 44.1K, 48K, Bit width: 16bit. CM6631 USB support frequency: 192K, Bit width: 24bit. Volume: Width 220MM * High 52MM * Deep 191MM Weight: 2.8KG Package list: 1 Finished TDA1543 USB Decoder