While developing the ADDAC105 4-Voice Cluster module, ADDAC created a brand new multimode filter to place after the summing mix stage. They were so pleased with it’s sound that they have now released this filter design as a dedicated VF module – The ADDAC604 Dual Filter!

The filter circuitry has been duplicated so that the module can be used in a stereo signal path. There is a switch to set the working mode from Stereo to Dual Mono where both filters can be used independently.

In Stereo Mode the Left Cutoff is used to control the Right Cutoff.
In this case the Right Cutoff Knob and CV Input are simply bypassed and will have no impact on the Right Channel operation.
This allows immediate sync of both filter frequencies when the Stereo position is engaged.
Optionally there’s a jumper in it’s back that, when placed, connects the Right Controls back to the Right CV control allowing the possibility to control the offset of the Right Channel Cutoff.

Resonance is independent on both Modes and still has to be set manually to match both channels.

Both the Audio and CV inputs are normalled from the Left into the Right channels.
As standard plugging any input to the Right channels removes this connection.

ADDAC604 – Assembly Guide | User Guide

Tech Specs:

• Width: 6HP
• Depth: 4cm
• Power consumption: 70mA +12V, 70mA -12V