Eurorack Zynthian

Has someone made a front plate for mounting zynthian in a eurorack?

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Not sure if anyone’s done a true eurorack version yet, but people have built rack-mounted zynthians already. A few examples:



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a custom made metal front plate would be cool. You can design an own one: https://www.schaeffer-ag.de/en/front-panel-designer but its not cheap.

Well what’s cheap. lol
I wanted to mount if with a Moog into an waldorf kb37.
so probably about 30 hp left if I through all other out.

AFAIK, nobody did it until now…but i’ve some ideas for doing it:

  • Have you thought about the RBPi position and securing?
  • Would you like to add CV/Gate jacks? I’m working on implementing the zynaptik “extras”, that would allow this.

Regards,

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Yes, but I haven’t looked up yet.
cv would be fine.or even more.
perhaps prototyping with fillament.
perhaps this panel if it should be there in the future
can be nice for your Webshop.
opens arms in other directions too.

This is a great idea. I’ve been thinking about that myself and will see if I can make some headway in that regard when I get back from my next work trip. I’ve been pondering using the zynthian in a eurorack suitcase alongside a synth and being able to route through effects on the rack. That would allow me to just carry my two midi keyboards and control the synth with one and the zynthian through my weighted setup for piano sounds via Pianoteq.

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I’ve been thinking about eurorack setup myself for a longer time, though not even tried zynthian yet. I What I have come up with such build requirements so far:

  • integrate DAC+ADC with adjustable Out and Rec volume using pots, extendable using RJ45 to breakout box, balanced would be perfect (3.5mm jacks)
  • integrate four additional buttons with extensions to 3.5mm jacks for external control (sustain pedals?)
  • connector plate to be removable, so in eurorack format it will mount side by zynthian main face, in boxed version it would be mounted on back
  • power should be able to accept standard barrel jack adapters
  • 2x MIDI IN-OUT (only on RPi 4), extendable using RJ45 breakout box, single IN OUT populated on 3.5mm jacks (space constraint)
  • on connector panel there should be also ethernet and USB (at least two) populated, this is so far major design issue, as this will have to be made using small cables between RPi ports and panel

So far where my experience is lagging is power and dac+adc design, so some collaboration in this area would be very welcome. Doing it all by myself is beyond my possibilities from time and effort perspective.

Hi,
for an ADC+DAC implementation used in a eurorack gear, have a look at mutable-instruments “clouds”, it’s open hardware design.

It use a wm8731 codec (not high end but well supported by the RPI ecosystem) and STM32 for controlling everything.
Schematic is available.

wm8731 provide:

  • software input gain control
  • line level output software control
  • headphone output (with integrated preamp) software control
  • software in/out mute + bypass
  • last but not least, everything is implemented in the linux driver and accessible through alsa controls.

I’m also in a design process for a customize zynthian pcb board but for an other use case: recording and processing electric guitar (HiZ) and dynamic microphone (balanced) signals.

Cheers.

I’d like to avoid these “low-spec” codec ICs. Your idea of Hi-Z and Microphone balanced input is great. Afterall, your design is then based around MI-Clouds design?

Except for the line inputs/outputs clouds design stick to the wolfson reference design.
For Hi-Z guitar and Microphone balanced inputs, the clouds buffer’s are not accurate I guess. They are designed to be use in an Eurorack environment.

Well, right now, project is more or less in stand by. Because of covid-19 I can’t get my hands on an oscilloscope to check the signal coming out from my guitars, bass and microphone and to test the input buffers (that still have to be built btw).
I have to say that I’m pretty new to all this stuff so it will be a long long story for sure :wink:

Here are the design that I plan to test:

This is for HiZ (from sonelec-musique)

This is for the dynamic mic input (from Elliot Sound Projects)

Regarding the codec, they are not a lot available on the market that will work “out of the box” with linux/raspberryPi
There’s the cs4272 wich has better specs but require more components and is not as versatile as wm8731.
You may have a look at these projects, they’re using cs4272 but are much more advanced:

Thanks for reference. I’ve had been through all those datasheets, but design audio boards is better to have experience with. Anyway, how do you plan to supply that -5V for opamp needs?

I plan to power the box with 3 (11,1V) or 4 (14,8V) Li ion cells and to use a virtual ground to create the negative rail.
https://www.diyaudio.com/forums/solid-state/234665-virtual-ground-regulated-rail-splitter.html
https://sound-au.com/project43.htm
https://tangentsoft.net/elec/vgrounds.html

They are also (step up or step down) converters IC’s designed for that task (eg: https://www.maximintegrated.com/en/design/technical-documents/app-notes/2/2026.html)