AJH Synth - MiniMod VCO (Black)

Discrete transistor VCO that captures the earliest Minimoog tone with modern stability and added modulation depth.

The MiniMod VCO Black is AJH Synth’s careful recreation of the oscillator found in the very first run of Minimoogs. Not the later revisions with op amps or arrays, but the early fully discrete transistor design. Around 300 of those originals were built, and this module focuses squarely on that character.

AJH keeps the circuit discrete, using individual transistors and period correct component values. The difference is in the stability. The temperature drift that plagued the earliest units is corrected by redesigning the CV summing stage. You get the same weight and harmonic texture, but it holds pitch properly in a modern system.

All classic Minimoog waveforms are available at individual outputs, including the sharktooth. This makes patching more flexible than the original keyboard ever allowed. You can process each waveform separately, layer them externally, or send different shapes to different destinations inside a larger Eurorack patch.

AJH also expands the feature set in useful ways. Pulse width is continuously variable and voltage controllable, rather than limited to fixed settings. Both exponential and linear FM are available, making it easier to move from subtle vibrato to more complex harmonic shifts. Two sync types with adjustable intensity let you dial in anything from gentle tightening to aggressive, tearing sync tones.

The octave switch drops the oscillator into LFO territory, and with negative control voltages it will run extremely slow. Integrated with the Doepfer bus, it can receive internal CV routing when no cable is patched to the 1V per octave input, keeping front panel patching clean in larger systems.

This is not a generic vintage style oscillator. It is a focused recreation of a very specific circuit, refined so it behaves reliably on a modern stage or in a tuned studio system.