AJH Synth-Mini Mod VCF (Black)

Discrete 24 dB transistor ladder filter that captures early Minimoog tone with added voltage control and drive options.

The MiniMod VCF Black recreates the low pass filter from the earliest Minimoogs, focusing on the fully discrete transistor ladder design. AJH matches the transistor pairs by hand, just as they were in the first production run, and runs the circuit at the same internal operating voltages as the original units from the early 1970s.

This is the classic 24 dB per octave transistor cascade. It delivers the familiar rounded low end, vocal midrange and smooth but assertive resonance that defined countless recordings. The response feels elastic under modulation, especially when driven from a lively oscillator or mixed waveform stack.

AJH extends the design in practical ways. Resonance is voltage controllable via a fast opto electronic component, allowing both slow sweeps and audio rate modulation. It tracks cleanly into self oscillation and can serve as a sine source when pushed.

Cutoff modulation includes standard 1V per octave tracking plus dedicated 1/3 and 2/3 volt per octave inputs that mirror the original Minimoog keyboard tracking switches. The additional exponential CV input is intentionally more sensitive and can be overdriven for aggressive filter movement.

Three audio inputs with individual level controls make it easy to build a Minimoog style voice without a separate mixer. A rear jumper lets you change the input stage behaviour for significantly more overdrive. In driven mode, the filter compresses and saturates in a very musical way, especially with multiple oscillators feeding it.

This module suits anyone building a vintage inspired mono voice, but it also holds its own in modern systems where voltage control and flexible routing matter just as much as tone.