Doepfer A-104 Quad Resonance Filter

The Doepfer A-104 is a quad bandpass filter based on the filter circuitry found in classic vintage vocoders. It features four parallel fixed-frequency bandpass filters, each with its own volume control, allowing you to emphasize specific frequency bands for sculpting formant-like textures, harmonically rich drones, or noise-based timbres.

This module excels at shaping sound in creative and expressive ways. Whether you're processing noise, pads, or complex audio sources, the A-104 adds depth and spectral character to any Eurorack system.

Key Features:

• 4 parallel fixed bandpass filters

• Inspired by classic analog vocoder circuits

• Individual volume control per band

• Ideal for formant shaping, texture layering, and timbral coloration

• Great for experimental, vocal-like, and noise-driven sound design