3-in-1 Subtractive Voice Module Overview The System80 810 MK2 is a 30 HP Eurorack module consisting of a high quality subtractive analog synthesizer voice: Voltage Controlled Oscillator (VCO), Voltage Controlled Filter (VCF), and Voltage Controlled Amplifier (VCA). More than just a clone, the design of each sub-module is inspired by the golden age of Japanese analog, featuring elements of the System 700, System 100m, and the Jupiter-8. Add some modulation and an envelope generator to create a complete patchable analog voice with a distinctly vintage character. VCO Discrete Voltage Controlled Oscillator with temperature compensated exponential converter 1 V/octave tracking over 7-8 octaves Sync input with weak and strong oscillator sync modes 1 V/octave CV input + two attenuated exponential CV inputs for pitch/frequency modulation Six position octave range switch Selectable waveform output: Pulse, Ramp, Triangle, or Sine Pulse Width Modulation CV input Sub-oscillator VCF Cascaded OTA design inspired by classic Roland topologies with selectable 12 or 24 dB response self-oscillating with 1 V/octave tracking (3-4 octaves, normalized to VCO KYBD CV input) VCO output and sub-oscillator normalized to two log attenuated inputs Two frequency CV inputs, one unipolar and one bipolar Voltage controlled resonance VCA Traditional single OTA design Three log attenuated audio inputs with IN 1 normalized to VCF output Two CV inputs with selectable exponential or linear response
