DAC. There was not much different between the U12 & U10 in term of technical specification. Besides, the new U12 now have LCD display on the font showing the bitrate and rate signal. The unit is slightly bigger than U10 .
However, the U12 is still very good using X-core XMOS chip since support 32bit 500MIPs with 8 cores USB receiver. And the use of the 0.1ppm audio clock making a prefect signal clock to digital interface.