All-in-one box with ES9023 DAC and Class D amp


after finishing my ES9018K2M project, I reworked an earlier prototype I built around a ES9023 DAC board. I wanted to build something that works with a power amplifier, as well as stand-alone with some bookshelf speakers, both on LAN and WLAN. It is powered by a 19V notebook-style power adapter and includes a 2x25W Class D amplifier.

Here are the ingredients:

  • Raspberry Pi B+ board
  • ES9023 DAC board from Audiophonics (also available on Ebay): 15 EUR
  • TDA7492 2x25W Class D amplifier from Sure Electronics (on Ebay), with 19V ACDC adapter: EUR 24
  • 1A DCDC converter (from Ebay): EUR 1
  • Alps Blue Velvet stereo potentiometer 10k log (salvaged from a preamp I built 20 years ago)
  • Hammond Electronics aluminum enclosure 22x16x5cm (could have been a bit larger, everything’s a bit tight): 24 EUR
  • Edimax EW-7811Un WLAN adapter: 8 EUR

COB including the smaller parts like the speaker connectors etc roughly 120 EUR.

The 19V power adapter feeds the Class D amp board. From there I tap VCC and feed the 19V into a DCDC converter board, that outputs 5V for the Pi. A parallel line goes to an LDO, that feeds the DAC board with 5V. The current draw on that line is not that high, so that the power dissipation in the LDO is ok without adding a heatsink.

After fighting for a couple of days with a nasty ground loop, that made me hear ethernet and WLAN activity, I could solve this issue by breaking the loop, and isolating the Pi’s power supply from the DAC. No more noise.

The sound with my Cyrus power amp and my fullrange system in my office is really great, and the performance from the Class D amp with a pair of vintage bookshelf speakers is good, too. I yet have to do a direct comparison.

Best regards,

This “sounds” great ! But why the hell do you need another amplifier when you already have a Cyrus power amplifier ? What about building a pre-amplifier ?

Anyway, I’ll be grateful if you don’t mind I copycat your all-in-one box.

I really like this setup.
I want to try and build something similar, for now without integrated amp, although I will reserve some space in the case for a future tweaks…
I got myself Raspberry Pi B+ and can’t wait to try it as soon as it arrives from eBay.
Next phase is a DAC, I’ve been eyeing the same one You have in your setup, or maybe HiFiberry DAC+, any advice on that?
after that comes PSU, I suppose decent linear one would suffice. Regarding that, I am interested how exactly did you filter power supply between RPi and DAC, it seams to me that it is mandatory because of RPi noise…?!
More Q’s later :wink:

Hello Roberto,

I believe the Hifiberry DAC+ and the ES9023 DAC should perform very similar, without having any experience with the Hifiberry. For those who care, an advantage of the Hifiberry over the ES9023 DAC board should be the hardware volume control and the seemingly better voltage regulator, although Hifiberry does not give details about the part (but neither does the company that produces the ES9023 board specify the type of their 3V3 LDO).

In my setup I have been using the 19V from the amp to feed a DCDC converter that outputs 5V to the RPi, and from the same 19V a TI LM2940 5V LDO that feeds the DAC board (a number of bypass caps are used here). Initially I have used the DCDC converter to produce an intermediate 7.5V (to reduce power dissipation in the LDO) and use the 5V LDO output for both RPi and the DAC. Here the effect of the a.m. ground loop was much larger. With the other setup it was still there, but only noticeable on high-efficiency speakers, but as mentioned before, I could break the loop and eliminate the noise altogether.

I’m not sure about your power supply setup, but it sounds like you only have 5V available, hence you cannot prefilter with an LDO. In that environment, I would experiment with a Pi filter (C-R-C) or a C-L-C filter, if you have problems with noise. And that’s maybe an argument for a discrete DAC board, instead of the add-on DAC, where you cannot filter the power supply.

Best regards,

Hello Toni,

congratulations to the clear and straight project!

My next project for the kitchen should be one with amplifier too. The new pi is an b+ too. Is it possible for you to show the wire-diagram from the dac to the pi b+? And which setting do you use in volumio for the dac?



P.S. Schöne Weihnachtsfeiertage und Grüße nach Kaufbeuren!

Hello Gerry,

Kaufbeuren was close. Augsburg is it :wink: The yellow pages gave it away…

Here’s the wiring scheme:

RPi B+ I2S pins --> DAC board
J8-39 --> GND
J8-12 --> BCK
J8-35 --> LRCK
J8-40 --> DATA

I have made the following manual changes to below config files, not sure if they are required or not. But IIRC I could not select “Generic” I2S driver and sound output “sndrpirpidac” without them.

root@volumio:~# sudo nano /etc/modules

snd_soc_core snd_soc_bcm2708_i2s bcm2708_dmaengine snd_soc_pcm1794a snd_soc_rpi_dac

root@volumio:~# sudo nano /etc/asound.conf

pcm.!default { type hw card 0 } ctl.!default { type hw card 0 }

Best regards,

Hi Toni,

Can you share what you use for volume control on that amp and how you have it wired?


I can see Alps pot that is wired in the signal path between DAC and amplifier.
There is also a direct connection to amplifier from outside (RCA), I believe it is for connecting a preamp source…

It is a 10k log Alps stereo potentiometer. I have connected the DAC output to its GND and input pins, and the amplifier to GND and the output pins. I have also diverted the post-Alps output signal to the RCA outputs.

Actually this is not good practice, since any external amp you connect to the RCA jacks “sees” the built-in amps input stage, but the sound is good. Eventually I’ll add a selector switch to chose between the nternal amp, and an external amp, but I’ve been busy with other stuff lately.

Along with that, I’ll probably add an additional RCA input, either into the amp directly, or into the ALPS pot. This should be also possible through a selector switch. Got myself a couple of those cheap from Ebay.

Best regards,