The Behringer 121 is a precise analog recreation of the Roland System 100M 121 Dual VCF module from the early 1980s. It provides two independent 24 dB/octave low-pass filters in a compact 16 HP package, each with resonance control, a built-in 3-channel audio mixer, three CV inputs for cutoff modulation, and a selectable fixed high-pass filter (HPF) per channel. Ideal for parallel filtering, stereo processing, multi-voice setups, or adding that classic Roland warmth and bite to any Eurorack system.
Technical Specifications
| Item | Description |
|---|---|
| Type | Legendary Analog Dual VCF Eurorack Module |
| Eurorack Width | 16 HP |
| Depth | 39 mm (1.5″) |
| Weight | Approx. 0.5 kg (1.1 lbs) / 3.04 oz (some listings) |
| Power Requirements | Eurorack bus (10-pin or 16-pin connector) |
| Current Draw | +12 V: 40 mA, –12 V: 40 mA, +5 V: 0 mA |
| VCF 1 & VCF 2 (identical) | |
| Filter Type | 24 dB/octave Low-Pass Filter (resonant) |
| Controls | CUTOFF FREQUENCY, RESONANCE (up to self-oscillation) |
| High-Pass Filter | Selectable fixed HPF per VCF: OFF / 1 kHz / 2 kHz / 5 kHz (resonance-free) |
| Audio Inputs | 3 × 3.5 mm TS per VCF (with individual SIG LEVEL attenuators) |
| Audio Mixer | 3-channel mixer per VCF for independent level control of inputs |
| CV Inputs | 3 × 3.5 mm TS per VCF (summed; with individual attenuators for cutoff modulation) Typical range: 0 V to +10 V |
| Audio Outputs | 3 × 3.5 mm TS per VCF (individual outs, likely including mixed/filtered signal), DC or AC coupled depending on path Max level: typical Eurorack 10 V p-p |
| Additional I/O | |
| Total Inputs per VCF | 3 audio + 3 CV (all with attenuators) |
| Total Patch Points | Extensive summed inputs, individual outputs per filter |
| LEDs | None (classic 100M minimalist design) |
Key Features & Signal Flow
- Two independent filters – Use separately for processing different signals, in parallel for thicker tones, or in series by patching one output to the other input.
- Built-in 3-channel mixers – Mix multiple audio sources directly into each filter without external modules; each input has its own level knob.
- Flexible CV modulation – Three CV inputs per filter with attenuators allow complex cutoff control from envelopes, LFOs, sequencers, or expression.
- Selectable HPF – Add fixed high-pass filtering (1/2/5 kHz) before the low-pass stage for band-pass responses or to sculpt highs without extra patching.
- Classic Roland System 100M sound – Smooth, musical filters with sweet resonance—great for creamy leads, punchy basses, or self-oscillating percussion.
- No normalisation – Fully patchable design encourages creative routing, multing, or cross-modulation with other modules.
Resources
- Official Behringer product page: https://www.behringer.com/product.html?modelCode=0720-AAG
- Quick Start Guide (PDF): Available on Behringer downloads, or direct links like https://notebook.zoeblade.com/Downloads/Documentation/Behringer/121_Dual_VCF_quick_start_guide.pdf
- ModularGrid page: https://modulargrid.net/e/behringer-system-100-121-dual-vcf
- Retailer pages (Sweetwater, Thomann, Alto Music): Detailed specs, user reviews, and demo videos
- Demo videos: Search YouTube for “Behringer 121 Dual VCF” (unboxings, sound demos, and filter comparisons)
The Behringer 121 delivers versatile, vintage-inspired filtering in a tiny footprint—perfect for expanding your System 100 series clone or adding dual-filter power to any rack without spending a fortune. Highly recommended for analog filter enthusiasts!
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