Doepfer A-101-1 Vactrol Steiner Filter

The Doepfer A-101-1 is a distinctive multimode filter based on the classic Steiner-Parker design, enhanced with vactrol-based control for smooth, organic modulation. It offers four filter types—low pass, high pass, band pass, and notch—available simultaneously via separate outputs. Known for its gritty and characterful tone, the A-101-1 provides rich resonance without quickly self-oscillating. Thanks to the vactrols, modulation inputs respond with a natural, fluid feel, making it ideal for expressive sound shaping. This module is a top choice for anyone seeking a filter with personality and analog warmth.

Key Features:

• Steiner-Parker inspired filter design

• Vactrol-based modulation for smooth dynamics

• Simultaneous LP, HP, BP, and Notch outputs

• Rich, raw resonance and unique tone

• CV inputs for cutoff and resonance control