EuroPi VS eurorack-awesome

Hi all, I'm making a Eurorack sequencer module with 4 pitch CV outputs (NOT audio) and I've noticed that DACs are kind of a pain due to being expensive, SMT-only & still requiring buffering with op amps. I figure that a good alternative would be to buy a Raspberry Pi Pico for $4 which will give me 8 PWM outputs that I would then hook up to an output stage like the one in the europi (shown here: https://github.com/Allen-Synthesis/EuroPi/blob/main/hardware/EuroPi/schematic/europi_schematic.pdf)

Bom has links for sourcing parts

Up until now I've been using the analog input stage from the EuroPi schematic as my model for a CV in. You can see it here:

There is no super cheap way to get a lot of analog outputs from an MCU. Filtered PWM is your best bet for cost effectiveness (I recommend looking at the EuroPi from allen synthesis : https://github.com/Allen-Synthesis/EuroPi). Otherwise if PWM doesn't work for you, you'll need to look into DAC chips. The MCP4728 is a good spot to start, it's 12-bit and has 4 channels: https://www.adafruit.com/product/4470. Since it's I2C controlled you can have multiple of them on one bus. Maybe looking into a 16 channel PWM driver for a lot of outputs: https://www.adafruit.com/product/815. Hope this helps!

The project is completely open-source and open hardware, and the contributors together have made this big list of scripts that you can run using a menu system!

The project is entirely open-source but I do also sell the Panel+PCBs on my site!

Check out the EuroPi project https://github.com/Allen-Synthesis/EuroPi

EuroPi Turing Machine script is feeding the Uncertainty cv input with pulse 1 opening an envelope on Maths for voice 1 & 2, pulse 2 opens the second Maths envelope for sub osc voice 3. A little delay added for texture. That's pretty much it!

EuroPi - A reprogrammable Eurorack module based on the Raspberry Pi Pico

The patch.init() is still a great way to start, but you could save some money ditching the audio i/o and build yourself an EuroPi. However, that requires DIY, obviously.

For open source gerbers you can send off to get made there is lots of stuff out there. This is a big list on Github. I've built the nickajeglin analog logic module which is really good. Maasijam has some really good stuff as well.

There's a good list in Eurorack-awesome although many are analog designs.

if you’re okay with 0-5v cv there are lots of references like https://github.com/mattb/teensy-cv. more here https://github.com/newdigate/eurorack-awesome

A good place to start is sdiy and the legendary modwiggler forum modwiggler or github. github

With that background, if you're comfortable with schematics and doing pcb layouts, open-source modules can be the cheapest way to go. Here is a link with a bunch of github repos. Some have gerber files, you can send off to somewhere like JLCPCB to have the panels and PCBs made. Minimum order is 5 I think.

You can get a lot cheaper with some of the open source stuff out there. Here is a link with a lot of stuff. You'll have to source companies to do panels and pcbs.