904A Voltage Controlled Low Pass Filter

Behringer 904A

The Behringer 904A is a voltage controlled low pass filter with a transistor ladder design inspired by one of the most iconic modular filters ever: the Moog 904A. The cutoff frequency features three frequency ranges to set the range of filtering. The cutoff frequency can be controlled by the fixed control voltage knob or with the three CV inputs. The cutoff frequency attenuates frequencies above the cutoff point, only letting lower frequencies through with a slope of 24dB/oct. Regeneration, or resonance as it's most commonly known, adds emphasis to the audio at the cutoff frequency through feedback. At high enough settings, the 904A will begin to self oscillate, acting as a sine wave oscillator.

904A Features

• Voltage controlled low pass filter
• Famous Moog-style 24db/oct transistor ladder design
• Three CV inputs
• Cutoff frequency and frequency range controls set the cutoff point
• Resonance self oscillates at high settings