1. DAC: ES9038Q2M is selected for the highest possible performance
  2. I/V stage/balanced output: 2 OPA1622 opamps are used as the I/V stage, creating a fully balanced output that can deliver 100mW into 32 ohms load. The opamps' output is biased by 15mA JFETs so that for a reasonably sensitive headphone with reasonably volume, the opamps are always in class A condition.
  3. Single ended output: 1 TPA6133A2 headphone amp is used to create single-ended, ground referenced output through a gold plated 3.5mm jack.
  4. Clock: Low phase noise audio grade 49.152MHz XO is used to generate MCK for the DAC.
  5. Supplies: 
    1. LM27762 is used as the first stage LDO to generate +4.3V and -4.3V rails from the USB +5V supply.
    2. 4 ultra low noise LDOs (LT3042) for DAC's DVCC/AVCC/VCCL/VCCR supplies, as the part of the second stage LDOs.
    3. 2 dedicated TPS7A39 dual LDOs for each channel, generating the +3.3V and -2.4V for the left and right channel I/V opamps.
    4. Dedicated digital power and ground for the RPi
    5. Dedicated analog power and ground generated by a isolated DC-DC converter for DAC and amps.
    6. Digital isolators are used for I2C and I2S signals.


  1. Custom driver is needed to use the DAC, please see https://github.com/VinnyLorrin/ES9038Q2M-Linux_Driver for the code and installation procedures.
  2. The DAC is operated in master mode and the internal NCO is used to generate precise data clocks for all supported sampling rate by using a single XO. The jittery RPi clock is avoided for the highest possible sound quality.
  3. DoP is functional with the custom driver


  1. The DAC datasheet can be found at http://file2.dzsc.com/product/18/05/25/829029_170233543.pdf
  2. The balanced output is NOT ground referenced. The common mode voltage is 1.65V, Do NOT short the balanced output to ground. Do NOT connect single-ended headphone into the balanced port.