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Interested in a multichannel RPi5 soundcard?

gordoste

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Joined
Nov 19, 2023
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Hi everyone, I have been working on a 6-in 8-out RPi5 soundcard. I will copy/paste my design parameters from the original thread:

  • Decent performance for reasonable price (<-90dB THD+N for ~$100AUD parts)
  • 8 channels out, 6+ channels in
  • At least 96kHz sampling rate
  • Full isolation from the Pi - so it will not use the Pi's power supply either.
  • Single-ended inputs/outputs
This is not supposed to be an audiophile device - it is just supposed to work (especially the first version). My particular use case is to allow a Pi to act as the brains of my DIY DSP-capable AVR, without needing to send the sound out over HDMI (this has some issues and takes up much more space).

My initial prototype circuit (documented here) had some flaws which I corrected and it is now fully functional. However, it became clear that the physical layout could do with some improvements. Specifically:
  • Move power, input & output circuitry to separate board, allowing the mainboard to comply with HAT form factor
  • Boards are 2-layer (cheaper than the prototype which was 4-layer)
  • Allow power/input/output boards to be separated from each other if desired
  • Ability to mount RCA sockets to the PCB
You can see pictures of the new design below. I am planning to manufacture a small number of each board soon. They will be hand-assembled by me.

What I'm wondering is whether anyone would be interested in testing one of these. I would charge you somewhere around $60USD, to cover the cost of components, plus you would need to cover shipping from Australia.

I believe this is the first multi-channel soundcard for the Raspberry Pi that has both inputs and outputs, and I am considering applying to launch on Crowdsupply if this testing is successful.

(FYI I will include both RCA sockets and headers so you can populate whichever you like).

Please comment below if you are interested in being involved and I will DM you.


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Very much interested in this! Thanks for your hard work on it, it’s crazy to me that no one had yet to come up with a solution for multichannel audio on the pi5!
 
Yes, this is hopefully going to be a significantly cheaper option than the Hifiberry boards for people who just want to experiment with a multichannel setup.
 
Also, some other differences - on my board the I2S clocks are generated by an external crystal (the RPi provides the clocks on theirs), and they are using the RPi's power supply whereas my board is isolated. Both of these should theoretically be advantages for my board's performance ... but we won't know until they're measured. On the other hand, my board only supports 96kHz whereas theirs is 192kHz. My goal is to be somewhere between "decent" and "surprisingly good".
 
Looks sweet.
1) Does this support 6 in and 8 out simultaneously?
2) Is there a driver and device tree overlay for this? I'd love to look at it.
3) Have you tried this on RPI4b?
 
Looks sweet.
1) Does this support 6 in and 8 out simultaneously?
2) Is there a driver and device tree overlay for this? I'd love to look at it.
3) Have you tried this on RPI4b?
1) Yes.
2) The prototype works well with just a device tree overlay and the simple-graph-card driver. It also needed a small customisation of the PCM3168A linux driver (look at the RPi github for details). The overlay and driver customisation have been accepted into the official Raspberry Pi 6.12.y source tree so you can see it there. A limitation currently is that if you forget to turn the board's power on before you load the overlay, it fails and cannot work until you reboot the Pi. Once I have the hardware side finalised, this will be the next priority (it needs a custom driver that allows you to run a command and get it to try again).
3) RPi4 only has stereo I2S support. It should work, but with only 2 channels in and out.
 
Hi! I would be super interested. I am really only looking for the inputs and it's impossible to find a board with more than two and they are usually just a stereo jack. I am a researcher recording underwater sound and we are looking to build a low cost, open source recorder to localize fish sounds (i.e., determine where they are coming from). Let me know how to get in touch!
 
I'm interested in this. If it can do 8 channels in and out I would immediately buy a few......
 
Have only just seen this now, bumping. I’ll inquire with a friend who could be interested. I personally am - just don’t have enough channels for proper testing atm
 
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