Microvolt 3901 is Pittsburgh Modular's software version of the Microvolt 3900 semi-modular synth. It models the hardware at component level and bundles a collection of the company's classic Eurorack modules, so you patch a small modular system rather than one fixed synth.
Seven oscillator sources, ten modulation sources and a full patch bay route audio and control voltage between modules, with every connection recalled in your project. A set of 19 effects can sit at the end of the chain or be patched inside the synth. The big change over the hardware is polyphony: up to six voices, or monophonic with up to six unison voices, where the desktop 3900 plays one note at a time.
It installs as Standalone, AU and VST3 on macOS, and Standalone and VST3 on Windows, with an iPad build on the way, and ships with 200 presets and a 7-day trial. Pittsburgh Modular sells it directly for $69. Set against Surge XT, Diva and Moog Model D, its draw is the West Coast-style patchability and the bundled modules. The full first look is in our Microvolt 3901 feature.