ADDAC System 4 Voice Cluster boasts four oscillators and plenty of modulation options

The Eurorack module features a VCA, FM switch and slew decay.

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ADDAC System 4 Voice Cluster

ADDAC System 4 Voice Cluster is said by the company to be “inspired by simplicity”. The four square oscillator comes as a result of the positive response received on ADDAC’s 103 T-Networks modules.

The System 4 has a selection of modulation options, including a VCA, an FM switch and a slew decay for the incoming trigger input. The four oscillators are summed and then processed through the multimode filter, offering lowpass, bandpass and highpass modes.

Each of the four voices has its own VCA input, where any input, including trigger, gate and CV, is accepted. The decay knob will control the amount of slew decay applied to the signal, muting the incoming signal if the knob is set to the maximum anti-clockwise position.

The FM switch can activate or deactivate the FM coming from the previous voice. The FM on voice 1 comes from voice 4, voice 3’s FM comes from voice 1, and so on, meaning each signal can be modulated in an FM loop.

External input can be routed via the back panel of the module, allowing the incoming signal to go through to the filter input for external audio, or all of the four voices’ frequency control. Plenty of experimental CV control over pitch on all four voices is on offer. To keep the module affordable, the inputs are not calibrated to 1v/octave.

ADDAC System 4 Voice Cluster is €110 and now shipping, and will also be available as a full DIY kit in the future. Find out more at


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