G-Storm Electro Pro VCF 3320 Filter Adaptation

The Pro VCF is a faithful adaptation of a well-known 4-pole synthesizer filter in Eurorack.  

The core of this design lies an Alfa AS3320 filter chip based on the original Curtis. Countless synthesizers used the 3320: Sequential Pro One, Prophet 5 rev 3, Drumtraks, Crumar Trilogy, Stratus, Elka Synthex, some Fairlight CMI, Linndrum, Oberheim OB-8, OB-Xa, PPG Wave 2

All full resonance the Pro VCF can self-oscillate.

FEATURES

• Two selectable filter slopes: original 24 db/oct, and 12 db/oct.
• Two voltage controlled input jacks for frequency CUTOFF w/ signal attenuators.
• A voltage controlled input jack for RESONANCE w/ a signal attenuator.
• Two signal input jacks w/ individual attenuators. At full clockwise, these inputs can overdrive the filter from most eurorack oscillators and audio sources.
• Includes a 10-pin to 16-pin Eurorack ribbon connector.

Specifications:

• Inputs - 2 Audio Inputs, 3 CV Inputs
• Outputs - 1 Mono Output
• Current – 10mA +12V, 11 -12V, 0mA +5V (not used)
• Depth - 22mm
• Width - 8HP, 40.5mm