VM900 921ABBB Oscillator

The VM921ABBB is a full-function oscillator bank. It can be used in the audio range, or as a low-frequency modulation source. It replicates the revised 921 oscillator design and has additional features compared to the earlier 901, including "clamping" (oscillator sync), pulse-width modulation, and extra wave outputs.

VM921ABBB replicates the unique oscillator driver/slave arrangement of classic Moog synthesizers. The concept is that the the Oscillator Driver module sets the overall coarse tuning as well as rectangular wave pulse width for the three slave oscillators. In the original hardware modular systems, the driver oscillator and slaves were connected internally. Any number of slave oscillators could be used, but the "one+three" combo was common, and we felt it represented a good compromise of utility and size. Though these have the appearance of four individual single-width modules, VM921ABBB is a single quad-width module.