Doepfer A-133-2 Dual VC Polarizer Slim

The Doepfer A-133-2 is a versatile dual voltage-controlled polarizer in a slimline form factor, offering a wide range of uses from basic VCA duties to advanced modulation processing and ring modulation. It builds on the original A-133 with several thoughtful improvements, including CV modulation inputs and dual-colour LED indicators for polarity feedback.

Each channel in the A-133-2 allows both positive and negative amplification of incoming signals, meaning it can act as a voltage-controlled inverter, attenuverter, or polarizer depending on how it’s patched. The amplification level is determined by a combination of the manual gain control, external CV, and CV attenuator.

A dedicated CV modulation input (Mod) allows for dynamic shaping of the control voltage itself. This opens the door for complex behaviours such as DC-coupled ring modulation with offset, or nested CV manipulation—ideal for feedback patches, wave shaping, or chaotic modulation schemes.

The Mod input is normalled to +5V, making it easy to use right out of the box, and a rear trimmer allows adjustment of its modulation range. The dual-colour LED provides immediate visual feedback of the current amplification polarity—yellow for positive, red for negative.

Whether you're looking to expand your modulation capabilities or explore voltage-controlled signal inversion and amplitude processing, the A-133-2 is a compact utility module with a huge sonic footprint.

Key Features

• Slimline dual voltage-controlled polarizer

• Acts as VCA, inverter, attenuverter, or ring modulator

• Bipolar amplification via manual + CV control

• CV modulation input for dynamic shaping of control voltages

• Normalled +5V on Mod input for immediate modulation

• Rear trimmer for adjusting modulation CV range (factory set to ±5V)

• DC-coupled for both audio and CV applications

• Dual-colour LED per channel shows current amplification polarity

• Width: 4HP

• Available in-store for demo