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Holonic Systems - VCV Rack Free Plugins from can communicate with various virtual and physical studio gear using MIDI and OSC protocols. Download the latest beta version from:

Table of Contents

Holonic Source

Holonic Source Receiver Demo

Holonic Source module for VCV Rack integrates with the iOS app and outputs CV control signals to VCV Rack.

  • 8 channels of CV control from to VCV Rack.
  • Per channel activity indicator, attenuator and low pass filter.
  • Multiple Holonic Source modules can run at the same time. Each instance can be set to receive on its own bus, from A to H, allowing for a total of 64 channels of CV.


We've put together some VCV demo patches that use the Holonic Source. They use the default mappings in the app.

Our demos are packaged with the plugins, they are located in: c:\Users\<you>\Documents\Rack\Plugins\HolonicSystems-Free\demos (Windows) /Users/<you>/Documents/Rack/plugins/HolonicSystems-Free/demos (MacOS)

The demo patches require the following VCV Rack plugins to be installed:

  • Amalgamated Harmonics
  • Audible Instruments
  • Befaco
  • Holonic Systems - Free
  • JW Modules
  • ML Modules
  • Valley
  • Vult Modules - Free
  • Some demo patches require Stellare Link. This module needs to be manually installed from Drop the zip in your plugin folder and restart Rack.

See also


Please check the following installation steps below to avoid common pitfalls, such as firewalls, and to ensure full functionality of the autodetection feature.

OSC Communication

mDNS/bonjour is used for autodiscovery.

  • MacOS
    • automatically detects VCV Rack when Holonic Source plugin is loaded.
  • Windows
    • requires Bonjour SDK from Apple to be installed:
    • Check that the Bonjour Service is running.
    • Run the script Holonic_Source_windows.bat. This script can be found in the plugin folder c:\Users\<you>\Documents\Rack\Plugins\HolonicSystems-Free\ The script publishes Holonic Source on the network to allow autodiscovery from app.
    • do not close the DOS window until your are done with your VCV Session.
  • Linux
    • Make sure Avahi is running (it is usually the case).
    • run the script. This publishes Holonic Source on the network to allow autodiscovery.
    • do not close the shell window until your are done with your VCV Session.


  • Ensure that firewalls, such as Little Snitch, are not blocking communication. For instance, on MacOS, with Little Snitch firewall, incoming communication must be specifically enabled for Rack.
  • If you cannot get auto discovery to work for some reason, you can always manually create an OSC output in and input your computer IP and port 9000.
  • Please read the manual

OSC Message Format

The Holonic Source OSC message format is used to ensure close integration with our app. In order to use Holonic Source with any OSC compatible application, please select Port 9000.

The message OSC path is /<bus>/<channel>/<mode> where:

  • <bus> is one of a/b/c/d/e/f/g/h
  • <channel> is one of 1/2/3/4/5/6/7/8
  • <mode> is one of cv for unipolar CV, cvbi for bipolar CV.
  • Argument value should be a float. Holonic Source accepts values in [-1,1] range or in [-10,10] range depending on the switch configuration in the GUI. When [-1,1] is selected, values will effectively be multiplied by 10.

Receiving Bus

The Receiving bus pot selects from which bus the module receives signals from This allows use of more than one instance of the module in the patch, providing up to 64 channels of voltage control in total.

Activity LEDs

Activity LEDs for each channel indicate when Holonic Source receives OSC messages for the particular channel and receiving bus.


Attenuators on each channel let one scale and invert CV values according to need.

Low Pass Filters

The slew is adjustable, in order to avoid stepped signals, and to make more natural CV changes.


VCV rack expects values between 0v and +10v for unipolar and between -5v and +5v for bipolar signals.

Holonic Source clips signals to -10v, +10v.

Ensure that values are properly scaled in the scaling section.



Sequence is a 8 step sequencer. One could see it as a A-155 / A-154 / A-152 merged into one module.



Pantry is a Dual CV/Gate Recorder/Looper.


  • Dual Channel.
  • CV and Gate Recording.
  • Record: Full loop length triggered or the button is pressed.
  • Overdub: Record while CV/button is held.
  • Pattern Length from 1 to 32 using CV.
  • CV control of Pattern Shift.

Swiss Cheese Knife


SwissCheeseKnife is a quad utility module with a twist.


Inverts input signal.


Signal attenuator.

Sample and Hold

Classic Trigger and Hold.


VCA with response shape ranging from linear to exponential.

Low Pass Filter

Simple low pass filter.

Slew Limiter

Slew limiter.

DC Offset Remover

While in AC mode, any DC offset is removed.


Signal offset.


Last on the signal path, but not least. SwissCheeseKnife can also mix 4 signals, as its outputs are normalled.



Gaps is a clock divider that supports multiple modes.

  • Integers: 2,3,4,5,6,7,8,9
  • Even : 2,4,6,8,10,12,14,16
  • Odd: 3,5,7,9,11,13,15,17
  • Prime: 2,3,5,7,11,13,17,19
  • Binary: 2,4,8,16,32,64,128,256
  • Random: random probabilities 1/2, 1/3, 1/4, 1/5, 1/6, 1/7, 1/8, 1/9
  • 8 step clock Sequencer



A simple dual switch. Two inputs, one output.

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