synthesis-technology/e440
E440 Discrete OTA VCF
Discrete OTA voltage-controlled lowpass filter with three simultaneous slope outputs (2-pole/12dB, 3-pole/18dB, 4-pole/24dB), voltage-controlled resonance, and input Drive control. Inspired by SSM2040 topology.415
Capabilities 3
- Lowpass Filterlowpass-filter
- All three outputs are lowpass responses sharing the same resonance and cutoff CVs; levels vary slightly between outputs due to the discrete OTA gain cell design.415
- Self-Oscillationself-oscillation
- Self-oscillates at high resonance (~9 tick on RESONANCE knob); outputs are phase-shifted 45 degrees apart, usable as a sine VCO with 1V/Oct tracking over 4 octaves.415
- Vcfvcf
- Discrete OTA design inspired by SSM2040 topology; three simultaneous lowpass outputs at 2-pole (12dB/oct), 3-pole (18dB/oct), and 4-pole (24dB/oct).415
Jacks 8 — 5 in / 3 out
| Name | Signal | Voltage | Description |
|---|---|---|---|
| Inputs (5) | |||
| 1V/Oct | cv | -5V to 5V | 415 |
| Audio In | audio | — | Signal input for the filter. Accepts any level up to 14V pk-pk; 50K nominal input impedance. Can be over-driven via the DRIVE control.415 |
| FM1 | cv | -5V to 5V | Filter frequency modulation input 1; routed through a standard attenuator knob.415 |
| FM2 | cv | -5V to 5V | Filter frequency modulation input 2; routed through a reversing attenuator knob (noon = max attenuation, CCW = inverted, CW = normal).415 |
| Res CV | cv | 0V to 5V | Resonance modulation CV input. No attenuator; range is 0V (no resonance) to +5V (full resonance).415 |
| Outputs (3) | |||
| 2 Pole Out | audio | -7V to 7V | 2-pole lowpass output at -12dB/octave slope.415 |
| 3 Pole Out | audio | -7V to 7V | 3-pole lowpass output at -18dB/octave slope.415 |
| 4 Pole Out | audio | -7V to 7V | 4-pole lowpass output at -24dB/octave slope.415 |
Parameters 6
| Name | Type | Range | Behavior |
|---|---|---|---|
| DRIVE | knob | — | Combination attenuator and booster amplifier (~2X gain) for the audio input. Can overdrive the filter to clipping (~14V pk-pk). Unity gain at approximately the 4th tick position. Can also boost line-level signals.415 |
| FM1 | knob | — | Standard attenuator for the FM1 CV input jack.415 |
| FM2 | knob | — | Reversing attenuator for the FM2 CV input. At 12:00 (noon) attenuation is maximum; CCW adds the inverted CV; CW adds the CV non-inverted.415 |
| FREQUENCY | knob | 20Hz – 18000Hz | Sets the cutoff frequency (or self-oscillation initial frequency). All 4 CV inputs are summed internally to determine the cutoff frequency.415 |
| JP1 | jumper | — | Enables or disables the bass boost enhancement on the filter output.415 |
| RESONANCE | knob | — | Sets the initial filter resonance. This knob setting is added to whatever CV is plugged into the RES CV jack. The filter will self-resonate (with no external applied CVs) at the ~9 tick mark.415 |
Firmware history 0 versions
No firmware history recorded.
References 2
- [415]
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[416]
Synthesis Technology E440 product pageproduct_page● verified 2026-05-16