Metasonix RK3 Eurorack Tube Ring/Shaper Module (Pre-owned)

A pre-owned Metasonix RK3 in good condition. It comes with original packaging and power cable

The RK3 is the latest version of our classic R-53 and TM-1 devices.

We’ve boiled the circuit down to its bare minimum size and form factor: one tube (a 14BL11 “Compactron” originally used in TV sets) in an 8hp module.

It’s very difficult to explain the RK3 in terms of “conventional” solid state electronic music equipment. It uses the tube in a way never seen before — until Metasonix came along. Waveshaping is provided by our special vacuum-tube “pulser” circuit that spits irregular pulses onto the input waveform. The pulses synchronize erratically with the input pitch (if a waveform with sharp transitions is used). Interaction and a strange sort of “resonance” occurs with the input pitch. The effect is very roughly similar to a (very weird) PLL sound effect. Combined with true vacuum-tube circuit distortion and primitive ring modulation, this can provide a vast range of complex, aggressive distortion effects, utterly unique in the world. It will take you years to fully exploit the RK3’s range of effects.

A basic ring-modulation function is also available in the unit–applying a carrier pitch from an external oscillator to the screen grid of the pentode, this allows making inharmonic sum-and-difference pitch sound effects, with a unique vacuum tube pentode sound. The carrier input can also be fed with control voltages.