Home > DIY HiFi > Building the $99 ES9018 DAC Board (Part II)

Building the $99 ES9018 DAC Board (Part II)

Updated 4/5/13

You can read part I here: [link]

You can also read another build log here: [link]


I have been able to identify 5 different versions. My board is V2. Each version has a new input pin configuration and/or other enhancements.

V1: Hardwired for I2S plus additional SPDIF iputs


V2 (my board). Access to all the inputs (must cut the shorting trace for I2S), more chip bypass.




V4. Introduces a contiguous ground plane (big deal) and other enhancements:


Another V4 board [link]:


V5. Separates AVCC-L and AVCC-R:



Easy mod to separate the power connections for AVCC for the right side and the left side.

The board neatly connects the left and right side AVCC pins as shown in this photo [link] of V4 of the board, showing the main trace for AVCC that is under the DAC chip.  On the other side of the board are bridges from the main trace to the individual AVCC pins. Cutting those bridges effectively separates AVCC-R from AVCC-L.

Board balanced layout-001

Here is a photo of V2. It seems that the bridge pattern matches the AVCC trace of the V4 board. I’ve measured the connections of all the bridges and they connect to AVCC.


Here is an overlay of the V2 board traces on the V4 front side photo. Seems like a workable solution. You can also see that each of the 8 AVCC pins has its own bypass capacitor. Hmmm, since there are 8 internal DACs in this chip, this means each internal DAC has its own supply pin.


Connecting  the AVCC-R traces together:


And cut the bridges:


Measurements confirm that the AVCC-R and AVCC-L are no longer connected. This mod should work at least in V2 and V4 boards.


Separately powering AVCC-L and AVCC-R has audible advantages as reported by diyinhk [link]:

Separating the ES9018 AVCC_R/L power supplies provide a much more 3D sound stage. The location of every instrumentals is much much more clear

It’s like listening the differences between an upright piano and a grand piano.

This is really a breakthrough even after many layout improvements since the first version. I finally know why many diy’ers want dual mono config or at least a seperate AVCC_R/L power supply.


One option is to use TPA’s AVCC which is a dual shunt regulator board. A diyer just did that [link]:


Since I updated the AVCC board in my BII DAC [link], I also have the older version to use.


Another option is to use the ESS opamp buffer as specified in the ESS documentation [link].


ESS specifies a single buffer for both channels, but this was for their original ES9018 evaluation board with a 40 MHz clock and 3.3V supply. If one uses a faster clock and increase the operating voltage a bit above the 3.3V, then the power requirement would be higher as shown in this graph:


Notice that if the clock frequency is 100 MHz, then the current requirement for AVCC at 3,3V is beyond 50 mA. Most opamps max out around 50 mA, thus using two opamp buffers makes a lot sense.

POOGE Regulators

Using POOGE 5.51 regulators [linlk] [link]



After upgrading my Buffalo II with the AVCC 2.1, the original AVCC v1 became available. No reason not to reuse it.

Removing AVCC module from BII: It wasn’t easy to desolder it from the BII (I had soldered the module to the pins rather than using the pin header for plug-in). Luckily the two “IN” connectors are tied together so connecting the input on one side is sufficient.


With cat-5 cables making 4 connectors, it can fit on the board connecting GND and AVCC L and AVCC R


Connecting to AVCC L pin and AVCC R pin (after separating AVCC) and ground pads


Perfect fit 🙂




The input to AVCC needs to be 5V (5.5V is maximum for this version of the AVCC board). It can be fed externally without connecting FB3. This way the AVCC/2 offset voltage used by the opamps can be generated without any modifications. For ultra-accuracy, the AVCC/2 offset voltage can be separated between L and R by using a similar resistor divider (externally implemented) for the other channel and by cutting the AVCC/2 offset line between L and R channels


I also tested it to ensure good working condition:


It is designed for 3.5V output. The output would settle to about 3.51V because the reference voltage is based on an LED and LEDs have a negative temperature coefficient, so as it warms up, its forward voltage decreases slightly.


This module has “uneven” LED brightness. It was like this since day one [link], but TPA assured me that it is of no consequence. I tested it with a 70 ohm load (drawing 50 mA per side) and measure the output with my rudimentary mini scope. The output looks clean.


  1. iancortez
    March 28, 2013 at 10:48

    Curious…. how and what will you use to power the the disconnected avcc?

  2. Anonymous
    March 28, 2013 at 16:55

    would it be possible to use the Twisted Pear Shunt in this application?

  3. BlgGear
    March 28, 2013 at 17:39

    Once you separate the AVCC R/L, then there are more possibilities. You can use TPA’s AVCC shunt for example. Or you can use one opamp buffer per channel as specified in the ESS recommendation documents or even the lowly TL431 shunt regulator :-). I haven’t decided what to use yet…

  4. Anonymous
    March 28, 2013 at 18:45

    I see Twisted Pear has the V1 trident shunts for $10, ordered one to try, not too familiar with them.

    • John
      March 28, 2013 at 18:48

      I am using the TP Tridents and AVCC on my board. It doesn’t look too good, but works great.

      • BlgGear
        March 28, 2013 at 19:47

        Got a photo?

    • BlgGear
      March 28, 2013 at 19:10

      Very nice 3.3V shunt regulator. Using the AVCC would require that you separate R and L

      • John
        March 28, 2013 at 20:05

        Actually you do not have to separate the R and L. I ran it for weeks with them tied together. Now I have them separated. I ran the positives to the legs of 0.1 caps that bypass pins 7, 10, 39 and 42. I ran the ground to the ground for each cap. You can use the TP Trident for the clock by removing the ferrite bead for the clock and adding the positive there. I will see if I can upload a photo in the DiyAudio thread.

      • BlgGear
        March 28, 2013 at 20:31

        My concern was that the two output voltages of the AVCC are not exactly the same. Not sure what the effects are since each side is trying to hold its voltage.
        Here [link] it says:

        Due to slight differences in the internal Reference inside an LDO, one regulator will dominate all the current when 2 or more are paralleled. Once the dominant LDO has reached its foldback current limit, or the voltage drop across its pass element (I x Rdson) causes its output voltage to drop, another parallel device will start providing power. Many LDO’s have a shutdown current limit and not a foldback. If a shutdown current limit is reached that LDO will turn off and not reduce the output voltage (foldback) to limit the current. In this case direct paralleling will not work. One method to force parallel operation is to put a resistance in series with each output, to compensate for the reference offsets Rdson variables.

  5. Anonymous
    March 28, 2013 at 19:16

    Do you know the difference between v1 $12 dual shunt and the current v3 for $40 ?

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