doepfer/a-124
A-124
Special voltage-controlled multimode filter with a cut-off slope of -12dB/octave, using the peculiar electronic circuitry of the EDP Wasp synthesizer. Abuses digital inverters as analog operational amplifiers. Has band-pass output and combined low/notch/high-pass output. Cannot self-oscillate.211
Visualization filter_response
Capabilities 1
- Multimode Filtermultimode-filter
- 211
Jacks 5 — 3 in / 2 out
| Name | Signal | Voltage | Description |
|---|---|---|---|
| Inputs (3) | |||
| Audio In | audio | — | 211 |
| CV 1 | cv | — | Voltage control input for cut-off frequency. Works approximately to the 1V/octave standard, though not very precise due to the simple Wasp filter design.211 |
| CV 2 | cv | — | Second voltage control input for cut-off frequency; level controlled by attenuator knob CV 2.211 |
| Outputs (2) | |||
| BP Out | audio | — | 211 |
| LP/HP Out | audio | — | Mixed low-pass/high-pass output. Mix knob blends from pure LP through notch to pure HP.211 |
Parameters 5
| Name | Type | Range | Behavior |
|---|---|---|---|
| CV 2 | knob | — | Attenuates the level of the voltage control signal applied at the CV 2 input, setting the intensity of modulation on the cut-off frequency.211 |
| Freq. | knob | — | Adjusts the cut-off frequency of the filter manually.211 |
| Lev. | knob | — | Attenuates the input level of the audio signal entering the filter. If the output is distorted, turn down unless distortion is desired.211 |
| Mix | knob | — | Adjusts the relative amounts of low-pass and high-pass signals at the LP/HP output. Fully counterclockwise gives pure low-pass; middle position gives notch; fully clockwise gives pure high-pass.211 |
| Res. | knob | — | Adjusts resonance (Q/emphasis), emphasising frequencies around the cut-off frequency. Cannot be driven to self-oscillation. In band-pass mode, higher Q narrows the bandwidth; in notch mode, higher Q narrows the rejected band.211 |
Firmware history 0 versions
No firmware history recorded.
References 2
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[211]
Doepfer A-124 Wasp Filter (VCF 5) Manualmanual● verified 2026-05-06
- [212]