AM8132 – CV Mixer (100M)


Roland 132 Module

Overview The Roland 132 was a dual four channel CV mixer  that was launched in 1979 along with the core Roland 100M VCO, VCF and VCA modules. It was not part of the base “D Set” system of 5 modules, but Roland sold around 2000 units over the next 3 years. It was particular useful in large multi-cabinet setups, to enable mixing of CV signals. I started designing a replica of the Roland 100M CV Mixer module in 2009 and again in 2018 but the project was put on hold, once Behringer released its own System 100M clones.

Initially Behringer planned separate 132 (see photo) and 165 modules, but they merged them into one module for production. Whilst this increased the feature count in a 16HP module, it compromised the features. The Dual Portamento lost its important MPX(Gate) input to select a second portamento range, and ended up with a 20mm slide potentiometers. The tiny rotary trimmers and cramped layout on the 132 make it hard to use in live performances.

In 2022 I restarted the AM8132 project to provide a slider pot based CV mixer, and the AM8165 project as an accurate replica of the Roland 165, complete with AS662 OTA chips. I worked with a panel manufacturer that makes powder coated panels with silk screen printing. This ensures the modules look like the originals, with grey panel and white lettering.

AM8132 Module

The AM8132 This is a set of two identical CV mixers in one 16HP module with 4x inputs each, and non-inverted and inverted outputs. Each input has its own jack socket and 20mm slide potentiometer. There are also two precision preset voltages controlled by 20mm sliders, providing 0 to +10v and 0 to -10V.

Each preset voltage has its own dedicated output jack, and the precision voltages default into In3 (+10v) and In4 (-10V) of each mixer, when no external signals are patched in. The front panel plays homage to the Roland 132 module with similar graphics and lettering.

The signal inputs and outputs are wide ranging +/-10V peak-to-peak. The circuit is based on RC4580 Op Amps and a precision +10V voltage reference.  No trimming is required, unlike the original Roland 132.

AM8132 PCB

There are 16x 3.5 mm jack sockets on the front panel:

  • 4x signal inputs for each mixer
  • Non-inverted and Inverted mix outputs for each mixer
  • 1x precision voltage output (0 to +10V)
  • 1x precision voltage output (0 to -10V)

Outcomes & Availability The revised AM8132 was sucessfully developed at the end of 2022 as a THD design. In June the module was redesigned into SMD components, to speed up production and to reduce the cost of the module, which I felt was too high at over £100 in THD. The revised module went into production in July 2023 at a retail price of £89. Visit our webstore to purchase one.

 

 

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