VCV Port of Befaco Percall


I saw a video on the Befaco Percall and thought it’d be a neat module to learn about VCV development / DSP etc. It’s a four channel envelope based mixer, great for generating percussive sounds.

I’ve forked the Befaco repo and added it there - if @Vortico is open to pull requests, I’d love to see it go into the library but if not (or if there are licensing issues etc), it will still have been a fun learning exercise. I’ve also only managed a windows build so far though I’m afraid.

This is my first time doing any DSP so any comments welcome. In particular I don’t have access to the hardware (yet, would be a fun module to pick up), so any input, e.g. on calibration of the envelopes would also be useful.

Brief demo video (no sound for the first bit!):


Well done, that would be a great addition to VCV Rack, I thought I had gone deaf until you put sound on for the last minute or so. Let’s hope Vortico allows this to be added to the library. Thanks for doing this.

Great work Hemmer thank you!

I’ll PM you a link to a Mac build I did which you can add to your repository.

I did get a build warning about deprecation so I’ll send you the terminal log of that as well.


Built for Linux this morning, no problems beyond some deprecation warnings. Untested yet but the build was easy.

I can supply a Linux dist build if you want.

Best regards,



Thanks for the help with the builds, I’ve pushed a commit that fixes those deprecation warnings up.

Just be carful to stay within the term spelled out in the manual:

VCV Plugin Ethics Guidelines

You may not clone the brand name, model name, logo, panel design, or layout of components (knobs, ports, switches, etc) of an existing hardware or software product without permission from its owner, regardless of whether these are covered under trademark/copyright law.

It is recommended to follow these guidelines for all plugins, but you are not legally obligated to do so. However, it is a requirement for:

distributing your plugin on the VCV Library.

obtaining a commercial plugin license.


Yeah absolutely. I wouldn’t submit to the library unless it was part of the existing Befaco collection. I was encouraged by this thread though as it seems like there’s possibility to port more modules in that collection. I’d even be interested in taking a look at those modules too (Burst, Muxlicer).


That would be cool. I believe it’s also specifically ok to take their code and put your own panel / logo / name on it. as long as the license on the source code says it’s ok.

Just tested it - excellent and very useful addition. Thanx a lot!

The Ethics Guideline is covered on this one. Befaco would be thrilled for more modules to be added to the Befaco VCV plugin.


Amazing… Great work!

1 Like

Great, good to hear it’s OK to add this into the mix. I’ve added the Mac build from @steve and and a linux build (myself, WSL, untested) to github. I’ll maybe reach out to Befaco and see if they have any other feedback, and also wait a little to see if anyone here picks up any issues.

Then is it just a case of submitting a pull request on the original repo (GitHub - VCVRack/Befaco: VCV Rack plugin based on Befaco Eurorack modules)?

1 Like

If I remember it correctly, Martin Lueders (ML modules) has done a polyphonic version of the Befaco EvenVCO for VCV 1.xx.

martin-lueders/Befaco: VCV Rack plugin based on Befaco Eurorack modules (

Maybe you can use this one and add a polyphonic version of the Percall ?
Or release the Percall as a different module, so that it doesn’t overrwrite the polyphonic module?


Yes please, +1 for merging the polyphonic version of EvenVCO into the mix.
That is the build i am using now, and i think many others as well.


Hemmer, hello there, is the ‘Befaco Percall’ going to be released through the library. It sounds like it has been given the go ahead from all concerned{?}. Thanks once again.

@rsmus7 / @Eurikon - I wasn’t aware of the poly version, but that makes a lot of sense. I’ve been in touch with Martin (@martinl1968) so hopefully we can sync up to provide a joint build at least (I’ve checked myself locally, the merge is trivial, see below).

@ady34 - as for getting things back in the library, there’s some discussion going on about how best to do that (especially as Andrew is very busy at the moment), but hopefully there’s a way to make it happen. I also need to do a bit of clean up and optimisation first.


If you are going to make a polyphonic EvenVCO you might look at my EV3, which uses about 1/3 the CPU, and is otherwise a clone. Oh, also implement the Sync that was left out of the original release. Just take the sync code from Fundamental VCO-1, it’s good.