A-121 Multimode Filter

The module is no longer in production. The A-121 is an early but very neat filter design by Doepfer. Unfortunately, the Curtis module CEM 3320 used is no longer available, so the module is no longer commercially available. It’s a shame because it has a very unique sound character and some interesting technical features. From … Read more

A-111-6 Miniature Synthesizer Voice

I often used my A-111-5 as a “stopgap” when I quickly needed another simple synthesizer voice and maybe was just too lazy to patch extra VCO, VCF, VCA, ADSR and LFOs for such a secondary voice . I was often plagued by the “guilty conscience of the modularist” when I ignored the far-reaching possibilities of … Read more

A-118-2 Noise / Random / T&H / S&H

The “Slim Line” module is a version of the classic analogue noise generator A-118-1 reduced to half the width (only 4HP). As with the other “Slim Line” modules, slightly smaller buttons and sockets with narrow, round nuts are also used here. The controls are at the top and the sockets are at the bottom, which … Read more

A-115 Audio Divider

The A-115 audio divider is a simple frequency divider that outputs square wave signals of 1/2, 1/4, 1/8 and 1/16 the frequency of the input signal. This corresponds to a tone 1, 2, 3 and 4 octaves below the input signal. User interface Inputs: Outputs: Controls: Suboscillator The A-115 Audio Divider can be used very … Read more

A-116 VC Waveform Processor

“Processor” here does not mean a processor in a computer, but simply an (analog) circuit that can change waveforms. Here the input signal is processed by two parallel circuits, the results of which are then mixed together: a clipper, which cuts the input signal sharply above a threshold, and a polarizer/attenuator, which can both attenuate … Read more

A-114 Ring Modulator

From a mathematical point of view, a ring modulator forms the product of two signals and then subtracts the sum of the signals from it: a * b – (a + b) Unfortunately, this great formula does not make us any smarter in terms of sound. Actually, this is “only” amplitude modulation, which, in contrast … Read more

A-112 VC Sampler / Wavetable Osc.

The A-112 is a small digital module that can record, store and play back transposed audio material – a sampler in small format. In addition, the module can also be used for simple wavetable synthesis and as an effects device. The module has two small memory banks (each 64 kbytes in size) to store audio … Read more

A-138f Dual 3-Way Crossfader

The A-138f is a small, dual, three-way crossfader. “Three-way” here means that we have three possible input signals and one output signal. You will look in vain for the extremely sophisticated options of the A-138e, which unfortunately is no longer manufactured. The A-138f simply fades between two signals “A” and “B” and then (from the … Read more

A-107 Multitype Morphing Filter

The module is no longer in production. The A-107 was basically an Xpander filter (A-106-6) with greatly expanded filter modes (36 instead of “only” 16) and a digital control for morphing between different filter modes. The filter itself is of course purely analog. The A-107 works with “filter chains”: Such a chain consists of a … Read more