WMDQAAF Quad Anti-Aliasing Filter


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The WMD QAAF (Quad Anti Aliasing Filter) is an expansion for the PDO intended to do away with aliasing and distortion that sometimes plagues digital to analog converters. The module can be used in tandem with the PDO, or separately as its own self-contained module. 

The QAAF features four independent -24dB/octave Butterworth filters that run at the same frequency with a slight pinch of resonance.

Additionally, the module’s frequency control circuitry is vactrol-controlled, meaning the filter response is slowed in response to transient signals, adding fundamental amounts of character to any sound. 

QAAF Features

  • Four 4-pole filters
  • Channel to Channel Freq +-0.5%
  • Switched Capacitor Design
  • Butterworth Response Curve
  • CV Input
  • Frequency Offset Knob
  • Clock Input/Output
  • Mix Output
  • Low-Frequency Limit Jumper
  • Great for Pre & Post Filtering


  • Eurorack Module
  • +12 rail: 35mA current draw
  • -12 rail: 35mA current draw
  • 4 HP Wide
  • Roughly 40mm deep
WMD QAAF Quad Anti-Aliasing Filter Reviews