I created a partial emulation of the ELTA Solar 42 using VCV Rack free modules. The patch emulates all 8 voices, the stereo mixer, the sequencer, the LFOs and the filters found in the hardware. There is a clean user interface and patch bay that is completely isolated from the guts of the emulator, so it is easy to work with.

Documentation is built into the patch.

The uploaded patch was used to create the accompanying video. It includes some modules patched into the patch bay that are not strictly part of the emulator – 6 Bernoulli Switches to randomly fade in and out the drone voices, and an Air Windows providing some reverb.

The Solar 42 is designed to be “played”, but this demo is entirely auto-generative. The Solar 42 requires all 22 oscillators and 2 modulators in the 6 drone voices to be tuned by ear. There are two V/Oct oscillators that work well with a sequencer (not included in my emulation, but can be patched in). However, I opted to tune everything by ear.

UPDATE 2024-04-4: Version 1 of the emulator had a serious bug – the FM CV for drone voices 1, 2, 6, 7 was completely broken. It didn’t effect the demo patch because it didn’t use the FM CV. The version has been incremented to 1.1 and the bug fixed.

I also used polyphony to reduce the number of Bernoulli Switches from 6 down to 1, without changing the character of the demo patch.

I also noticed that I have not quite implemented voices 1, 2, 6, 7 correctly, as I am using linear FM, but the Solar 42 is neither linear nor exponential. I hope to release a version 2 soon that corrects those voices, and also adds external inputs, and some other inputs/outputs to the patch bay.