Blue Nautilus AcidusVersio is an alternative firmware for the Noise Engineering Versio module, turning it into a TB-303 emulator.
Just before Christmas 2025, the fantastic Noise Engineering Versio platform received its 11th algorithm: Granulita Versio, a free granular synth/processor.
What few people know is that you can also design your own algorithms. This is enabled by the Daisy platform on which the Versio modules are built. One code that flies somewhat under the radar is the Blue Nautilus Acidus Versio. This free firmware transforms the module into a well-known Roland acid synth.
Blue Nautilus Acidus Versio
Acidus Versio is a 100% free alternative firmware for the Noise Engineering Versio module, turning it into a Roland TB-303 emulator for your rack.
According to Blue Nautilus, Acidus Versio is based on a port of Robin Schmid’s open303 code, an open-source TB-303 emulator. Once updated via the USB port on the back, your Versio module is a complete synth voice.
The module provides hands-on control over pitch, cutoff, resonance, decay, slide, envelope mod, and accent. Yes, the two 3-way switches on the Acidus Versio are also mapped with features.
The first switch lets you toggle between the waveform: saw and square, and in the middle, a morphed waveform halfway between.
Then, the second controls the range of the values available for each knob with three modes: Baby Fish (sweetspot mode), Momma (less restricted), and Devil Fish (full range).
Furthermore, as is typical for a Eurorack module, there are also CV inputs for the parameters.
First Impression
A great alternative firmware for the Versio module range. If you know of any other hidden-gem alternative firmware versions, please list them in the comments.
Blue Nautilus Acidus Versio firmware is now available as a free download from the developer’s GitHub. You can buy an alternative faceplate from Modular Bias.
More information here: GitHub / Modular Bias
Be the first to comment