904A Voltage Controlled Low Pass Filter

The Behringer 904A Voltage Controlled Low Pass Filter is an authentic, all-analog recreation of arguably the most famous filter in synthesizer history: the Moog 904A. This module brings the legendary, patented transistor ladder filter sound of the 900 series into the Eurorack format. Renowned for its rich, warm, and fat sound, this 24 dB/octave low-pass filter is responsible for the classic bass and lead sounds that defined entire genres of music. It is an essential component for anyone looking to achieve that iconic vintage Moog sound in their modular system.

The 904A is straightforward yet incredibly powerful. It features a large knob for manually controlling the cutoff frequency, which determines where the high frequencies are attenuated. A second knob controls the filter's resonance (or "Regeneration"), which adds a resonant peak at the cutoff frequency for more pronounced filter effects. At high settings, the filter will self-oscillate, producing a pure sine wave. The filter's cutoff frequency can be controlled via three separate CV inputs, allowing you to create expressive filter sweeps and dynamic tonal changes using envelopes, LFOs, or any other CV source. This is not just a filter; it's a legendary piece of synthesis history for your rack.

Features

• Authentic recreation of the legendary Moog Modular 904A VCLPF.
• Classic 24 dB/octave transistor ladder filter design.
• Delivers the famously rich, warm, and powerful Moog filter sound.
• Manual controls for Fixed Control Voltage (Frequency) and Regeneration (Resonance).
• Three CV inputs for external control of the filter cutoff.
• Capable of self-oscillation at high resonance settings.
• All-analog circuitry for a true vintage experience.
• The cornerstone module for classic subtractive synthesis.