Company: Doepfer
Released: 1995

The Doepfer A-100 analogue modular system is a collection of modules that can be linked together with patch cables to form a complex synthesiser. Its main rival is the Analogue Systems RS Integrator system. While the RS Integrator is housed in a beautiful, wooden case, the A-100 is much more sensibly priced and contains some downright fun modules.

A brief overview of the more interesting modules

A-106 Xtreme Filter Starting off life as a clone of the filter in Korg's MS-20, this has since been improved to have more extreme distortion effects and is more versatile due to the extra controls.

A-119 External Input / Envelope Follower External audio signals (such as, say, an electric guitar) can be processed with the A-100 using this module. A gate signal is generated once the input goes above an adjustable threshold, so the A-100 can tell when a new note or sound has been started.

A-124 Wasp Multimode Filter Another interesting filter from an old synthesiser, this is modelled on the filter of the lesser known Wasp: a cheap keyboard with a black and yellow colour scheme. It's nice to know that such gritty filters are recreated, along with the regular, clean ones that you'd expect to find in a modular system.

A-178 Theremin Control Voltage Source Possibly the most fun add-on to any synthesiser, this module features a Theremin-style antenna. Unlike the Theremin, which has one antenna to control the pitch and another to control the volume, this module's output can naturally be wired into any other module's input, so your hand movements can control anything from a filter's cutoff point to the speed of an LFO.

A-198 Trautonium Manual / Ribbon Controller If the A-178 is the most fun controller, this is the second most fun. The ribbon controller interface is essentially a long stick that you slide your finger along. Two different outputs are determined by the position of your finger and by the amount of pressure you are applying. It would make sense to rig it up so that the position of your finger controls an oscillator's pitch and the amount of force you apply controls an attenuator, but, as with all modules, you can patch the outputs into any inputs in the system.

A-199 Spring Reverb Long before digital reverbs existed, there were several imaginative ways of achieving an echo, the cheapest of which was to use springs. This module houses three such springs, causing a distinctive type of reverb quite different from that produced by modern methods.


Out of all the currently available modular systems, the A-100 offers the most variety with its modules. From gritty filters to surreal controllers, it offers many fun additions to the regular oscillators and attenuators. As if that isn't enough, it's also more sensibly priced than its main competitor. Musicians have never had it so good.

This writeup is in the public domain.