3xOsc

3xOsc | 3 VCO Eurorack Module

This is a Eurorack format VCO synth module, based on Moritz Klein's VCO design.

The module was designed using KiCad.

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Features:

Each of the 3 oscillators has:

• Coarse and fine tuning knobs
• a PWM (Pulse-width Modulation) knob
• a FM (Frequency Modulation) knob and CV (Control Voltage) input

Controls unique to each oscillator:

• Oscillator 1:
  • Saw/Pulse switch
• Oscillator 2:
  • Saw/Pulse wave mix knob
• Oscillator 3:
  • Saw/Pulse switch
  • PWM modulation input, and modulation amount knob

Build Guide

1. Download the Gerber files from each board's '.gerbers' folder.
2. If you want to make any modifications to the schematics, download the schematics, make your modifications, and regenerate new Gerbers
3. View the components required from the BOM.csv file. (If you have made any changes to the schematics, it is best to regenerate the BOMs).
4. Order all the components needed
5. Send the Gerber files for PCB manufacturing, you can use PCBShopper to compare prices across various manufacturers.
6. Assemble the module

• Notes
  • Generic 1/4W 1% resistors will work for the build.
  • The potentiometers are all linear.
    • For the coarse tuning knobs, you can use logarithmic pots if you prefer.
  • In addition to the components in the BOM, you will need M3 bolts to mount the module into your case, and hex nuts to mount the front panel onto the components (these usually come packaged with all the interface components).

Once you have your PCBs and components, refer to the BOM and schematic to solder the components onto the board.

The module is split into three boards, the main board, the connector board, and the front panel. You can make your own front panel if you'd prefer.

The front panel board has no electrical connections and is purely aesthetic. I recommend letting your PCB manufacturer know this to avoid any issues.

The main and connector board are connected via the pin headers on the top and bottom of the PCBs, make sure you orient the pin headers properly before soldering. The front panel is secured onto the connector board using hex nuts.

Front Panel

To view the front panel on KiCad, you need to install the fonts in the fonts/ folder from this repo, or replace them with your font of choice.

To get the shiny gold finish for the exposed copper used for text/graphics, make sure you get your PCB manufactured with an ENIG finish. Most PCB manufacturers offer this as an option.

I went for a black solder mask, but you get the option to choose from many different colours when ordering your PCB.

Contributing

Pull requests are the best way to propose changes to the schematics.

1. Fork the repo and create your branch from master.
2. Make your changes to the design.
3. If your change directly affects the module's functionality, update the documentation.
4. Issue pull request

Any contributions you make will be under the GPL Software License

In short, when you submit code changes, your submissions are understood to be under the same GPL license that covers the project.

Report issues using Github's Issues tab.

I use GitHub issues to track public bugs. Report a bug by opening a new issue.

Issue Reports tend to have:

• A quick summary and/or background
• Steps to reproduce
  • Be specific
• What you expected would happen
• What actually happens
• Notes (possibly including why you think this might be happening, or stuff you tried that didn't work)