Voltage Modular is a free VST/AU virtual “modular case” for macOS and Windows compatible with most DAWs. It also runs as a Stand-Alone soft-synth.

Developers can freely design and publish modules with the equally free Voltage Modular Designer, and there’s a bunch of both free and paid modules available from a range of DYI as well as more established vendors.

PSP PolyPack is a set of PSP modules for Voltage Modular designed to assist you to help you build polyphonic instrument racks.

The wide set of features included in these modules combine flexibility and creativity within simple to use modules.