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Dual Twin (Eurorack: Pre-Order)

Dual Twin (Eurorack: Pre-Order)

Regular price $327.00 USD
Regular price Sale price $327.00 USD

Dual Twin

The Aulos series is the new brainchild of legendary synthesizer designer Bert Vermeulen of Synton / Fénix.  The goal is a compact and  fully analog series of synthesiyer modules!   It will be available in a variety of small formats, including Eurorack and stand alone tabletop Banana instruments!!!

Pre-Order - ETA 2-6 Months.   Will have a Metal Panel and Proper printed Logos.  (Photo is early version prototype)

If you want a stand-alone Banana Version, Please reach out. 


DualTwin are 4 filters which are configured in 2 pairs of filters with routing switches. The filters can be used in stereo or patched in mono.

Current Draw @ +12v 34mA -12v 38mA.
Module size:18HP

The DualTwin has 4 voltage-controlled State Variable Filters. 

2 filters are set parallel by a 3-position switch. 

The routing of each pair of filters are:

  • BP - BP
  • BP- LP
  • (LP) – LP

(LP) is an inverted LP output. In the (LP) – LP position the inverted LP adds to the other (non inverted) LP. This will mute the signal if both are in the pass band AND if both input signals are the same. This result is a bandpass filter.

See diagram.

If using 2 different input signals, both filters work as a normal LP filter, except that 1 output is inverted.



  • Each filter has its own audio input. 
  • The second input of the filter is connected to the first input if the second input is not used.
  • In-All is an audio input which goes to all 4 filters.


  • Each pair of filters has its own output.
  • The outputs are actually VCA’s! If the cv input (VCA) is not used the VCA is
  • There are mix inputs for adding other signals.


CV Controls:


  • The CV1..4 are the control voltage input for the freq of the filters. The control voltage is added to the freq potmeters.
  • CV1 is connected to CV2 if CV2 is not used.
  • CV3 is connected to CV4 if CV4 is not used.
  • CV-All is a control voltage input for all filters


  • The Res1..4 are the control voltage input for the resonance of the filters.
  • The control voltage is added to the resonance potmeters.
  • Res1 is connected to Res2 if Res2 is not used
  • Res3 is connected to Res4 if Res4 is not used
  • The Filters can be oscillate when the resonance pot is set high


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