CG Products
design — construction — sound

Eurorack Module


Dual Precision Adder/Comparator with each 3 Inputs

2 Precision adders/comparators each with 3 inputs suitable for audio and/or CV signals. The switch position decides which mode is selected. In ‚Σ‘ mode, the circuit functions as an adder with amplification = 1,00. By patching one signal to 2 or 3 inputs, amplification factors of ·2,00 or ·3,00 can be set.
In ‚Comp‘ mode, the circuit works as a comparator with a slightly schmitt-trigger-like characteristic. Depending on the level of the inputs, the output voltage is switched between either +5V or -5V, suitable as gate/trigger, squarewave/pulse audio signal etc. The threshold level of switching between these voltages is ≈0V; e.g. for an input sum signal > 0V, the output signal will be +5V, for an input sum < 0V it will be -5V. So, the threshold level can be shifted by applying an offset or control voltage on one of the inputs.
Applications such as pulse width modulation or +/- voltage detection can be easily realized.


Add1 Minijack
  • Audio signal mixing
  • CV signal mixing
  • High precision, suitable for frequency CVs
  • Switchable comparator mode
  • Signal-to-squarewave conversion
  • Available with banana or 3,5mm minijacks
  • Eurorack module
  • Width: 6 HP
  • Dimensions: 128,5 mm x 30,2 mm
  • Depth: 30mm
  • Supply voltage: ±12V
  • Current consumption (postive rail, without load): ≈10mA

PDF Download
Add1 PDF documentation

Add1-MJ Drawing

Add1 - side view right

Side view right
Add1 - side view left

Side view left I
Add1 - Banana version - side view left

Banana version
Add1 Addition Mode Waveforms Add1 Comparator Mode Waveforms