HM9791: Dual digital oscillator with internal modulation bus

For those that prefer the look and unique sound of vintage digital modular, this is the mk1 version of the Hertz Donut. Heavy aliasing included.

Dual digital oscillator with internal modulation bus. voltage-controlled waveform discontinuity, internal pitch tracking with several lag settings. dedicated square wave outputs, and a multi-purpose gate/xor ring mod output.

Specifications

Main oscillator

• waveform output (switchable between saw, tri and sine, 12-bit resolution)
• waveform discontinuity modulation variable square wave output
• hard digital synchronization input

Modulation oscillator

• sine, tri or saw waveform
• independent square wave output
• selectable modulation frequency range
• hard digital synchronization input
• oscillator output internally patchable to main oscillator frequency (linear, thru-zero), amplitude, or discontinuity
• internal modulation index voltage-controllable
• variable-lag pitch tracking of primary oscillator
• general-purpose gate output for monitoring internal tracking status

Compatible with Livewire X-Mod and Audio Compositor expansions.

(power tested in 2023 with a test3 under moderate cv with many lights lit. +12 idles around 130mA)