Pure modular synthesis. All songs played on a Pittsburgh Modular Foundation 3, a 4MS Company VCA Matrix, a Korg MS-20 (used only for voltage odds and ends), a simple 1-channel 16-step sequencer, and a few fx pedals (JHS Colour Box, Strymon Deco, Eventide Timefactor, and an Eventide Space).
The two Randyman songs feature the Vermona Drm1 Mk3 kick and snare, triggered by the sequencer gate and an output of the VCA Matrix, respectively.