Dual-Mode Analog Filter
EFI is an analog multi-mode filter that is loosely based on the KORG MS-20 filter, but has been improved to fit into a 4 HP module.
It has a Low Pass and High Pass Mode which you may choose via Switch on the front panel. Additionally there are two CV inputs with an attenuator each.
Resonance can self-oscillate and there is a third mode that you may choose via jumper on the back. In this mode Resonance will be overdriven very quickly in Low Pass Mode and you will get some nice liquid sounding overtones.
This module is very easy to build and only needs 24 different components that are quite easy to source.
• Analog Dual-Mode-Filter
• Filter Modes: LP, HP (+ LP Overdrive via Jumper)
• Resonance Control
• Two CV Inputs
• Two CV Attenuators
• Wrong Polarity Protection
• 3U Eurorack module, 4 HP wide
The module consists of two boards:
• Front PCB Panel
• Main PCB
- 26 mA +12V
- 24 mA -12V
- 0 mA 5V
- 25 mm deep