Befaco A*B+C
Dual-channel analog multiply-add utility for audio and CV
6 HP Eurorack module
A*B+C is a dual-channel analog utility module that performs the mathematical operation (A×B)+C on audio and control voltage signals, enabling multiplication, addition, and attenuation in a single module. It functions as a ring modulator, VCA, mixer, attenuverter, DC offset generator, signal splitter, and more, making it an extremely versatile building block for complex signal interactions and timbral transformations.
Features
- Dual channel (A×B)+C analog computation
- Four-quadrant multiplication enabling true ring modulation
- B and C inputs normalled to 5V for immediate use without patching
- A1 normalled to A2 in MULT mode for signal splitting
- OUT1 normalled to mix bus in MIX mode for two-channel mixing
- Gain switches on B and C paths: x1, x2, or x-1 per channel
- Manual attenuator knobs for B and C on each channel
- Internal division by 5 to maintain modular-appropriate voltage levels
- Voltage clipping at +/-10V for signal protection and distortion effect
- LED level indicators per channel: green for positive, red for negative
- Accepts signals from +/-10V range on all inputs
- Functions include: ring modulation, linear VCA, CV mixer, attenuverter, DC offset generator, phase inverter, signal multiplier, voltage-controlled attenuator, 2x amplifier
Controls & Jacks (16)
- A1
- B1 Level
- B1
- C1
- OUT1
- OUT1 LED
- A2
- B2 Level
- B2
- C2 Level
- C2
- OUT2 LED
- OUT2
- Mode
- C1 Level
- B2 Level
How-To Guides
- Classic Ring Modulation
- Linear VCA with CV Control
- DC Offset and CV Attenuverter
- Voltage-Controlled Attenuverter
- Two-Channel CV Mixer with Offsets
- Signal Splitter (Buffered-style Mult)
- Hard Clipping Distortion
- Amplitude Modulation Tremolo
- CV Scaling and Transposition
- Parallel Dual-Filter Modulation
Explore the interactive A*B+C panel on BleepDex — tap any control to learn what it does.