Rotomatic

Rotomatic cabinet — wide cinematic studio shot, smoky room, light spilling in from above, glowing valves visible at the bottom of the cabinet.

Plate I. · Control surface · Width · Drive · Mix · Speed · Depth · Balance

Rotomatic control panel — six knobs on walnut, two VU meters, brass Amelia Audio plate.

The anatomy of analog.

The horn rotor

Two opposing bakelite horns on a wooden platter, modelled with the throw, room reflection, and the moment when the horn passes the microphone — when the swirl turns into a chop.

Doppler from physics.

Pitch wobble and phase cancellation computed from the rotor's actual angular velocity past the mic capsule. No chorus, no flanger shortcut. The swirl is the consequence of the cabinet, not a side effect.

The Rotomatic valve amp — three glowing power tubes in a wooden cabinet.

Push-pull valve drive.

A 40-watt push-pull valve amp, modelled stage by stage. Clean at low drive, blooming through unity, sagging and singing when you push the front end past where you should. Used alone, a pure tube saturator.

Modelled from the original schematic.

The classic 122-style amplifier and crossover — a single-ended driver stage, a push-pull valve output, a dividing network feeding the horn and drum motors. The full circuit, line by line.