Recent Posts

  • A-131 Exponential Voltage Controlled Amplifier
    The A-131 module is the “sibling module” of the A-130 VCA. In contrast to this, it works with an exponential characteristic, but is otherwise identical. This makes it rather unsuitable for amplifying control voltages, but in most cases it is very suitable for amplifying audio signals. User interface Inputs: Outputs: Controls: A slightly “coloring” VCA … Read more
  • A-121-2 12 dB Multimode Filter
    Like its predecessor A-121, the A-121-2 filter is a multimode filter with 12dB slope that offers separate outputs for highpass, lowpass, bandpass and notch (bandstop). Technically, the filter is a direct offshoot of the “Dark Energy II” synthesizer, which basically uses the same circuitry. How does it sound? Fine, round, pleasant and in terms of … Read more
  • A-120 24dB Low Pass Filter
    The A-120 module is – the name “Low Pass 1” suggests it – something like the “mother of all Doepfer filters” (from a historical perspective, not from a technical perspective). The circuit is based on the famous 24 dB Moog transistor cascade (“ladder” filter). And this is actually the official mother of all synthesizer filters. … Read more
  • A-119 External Input / Envelope Follower
    The idea of running an audio signal such as vocals or drums through a modular system is always popular – with hopefully musically usable output. In addition to the often heard filtered drums, you can of course do a lot of creative things this way. The A-119 module performs several tasks: User interface Inputs: Outputs: … Read more
  • A-130-8 Octal Linear VCA
    It’s hard to imagine even more VCAs in a small space than the A-130-8 allows. No fewer than eight independent, linear VCAs are housed here in just 6HP. And because there was still some space on the front panel, there are also sum outputs for inputs 1-4, 5-8 or for all inputs 1-8 together. So … Read more
  • A-111-5 Mini Synthesizer Voice
    The A-111-5 is not an oscillator in the traditional sense, but a complete mini synthesizer with VCO, VCF, VCA, ADSR and two LFOs. A “Dark Energy” (first generation) for the modular system! A lot of things here are patchable, but upon closer inspection you’ll see that some signal paths are exclusively internal. For example, there … Read more
  • A-130 Linear Voltage Controlled Amplifier
    The A-130 Voltage Controlled Amplifier is a (very well-equipped) linear VCA. The “sibling module” A-131 works with exponential characteristics, but is otherwise identically equipped. It has already been shown with the mixers A-138a (linear) and A-138b (exponential) that an exponential characteristic of the amplification comes closer to our psychophysiological feeling of a “perceived linear” volume … Read more
  • A-111-1 High End VCO
    The module is no longer in production. The A-111-1 was the high-end model among Doepfer’s oscillators and is only available on the used market. The successor model with some detailed improvements is the A-111-2. Compared to the A-110-1 or A-110-2, the A-111-1 offers expanded synchronization options, an additional input for linear frequency modulation, and a … Read more
  • A-121s Stereo Multimode VCF
    Does this sound familiar? A new module enters the market and your first thought is: Oh, I know that one, I already have one of these, two in one housing – so what… I’ll take another look anyway: Oh, morphing between filter types, even via CV. Lots of control inputs, common for both filters, separate … Read more
  • A-111-3 Micro Precision VCO / VCLFO
    An almost ideal VCO for small, portable module systems: The A-111-3 measures just 4 TE! At its core, it is the same VCO as the A-111-2 High End VCO II, which, however, is much more luxuriously equipped. So, again, we’re dealing with a highly tuning stable oscillator that offers pretty perfect tracking of 1V/octave over … Read more
  • A-171-4 Quad VC Slew Limiter
    The A-171-4 Quad Slew Limiter is the youngest member of Doepfer’s family of polyphonic modules. What they all have in common is a four-fold layout of the functionality. All of these are influenced by common controllers and/or common control voltages. In addition, all Poly modules (at least in current production) have the option of internal … Read more
  • A-129 / 5 Voiced/Unvoiced Detector
    The module is no longer in production. The principle of the vocoder has problems with unvoiced modulator signals: For example, the hissing and explosive sounds when speaking (s, sh, t, p, etc.). If they are processed like vowels, the speech intelligibility of the result is usually not particularly high. That’s why vocoders often have modules … Read more
  • A-129 / 4 Slew Limiter Controller
    The module is no longer in production. The A-129 / 4 is purely an add-on module for up to three A-129 / 3 Vocoder Slew Limiters. This can be used to control the speed with which the control voltages are passed on from the inputs of an A-129 / 3 to the outputs (slew limiter … Read more
  • A-129 / 3 Vocoder Slew Limiter
    The module is no longer in production. The attenuator / slew limiter can be switched between the analysis unit A-129 / 1 and the synthesis unit A-129 / 2. This allows individual frequency bands to be attenuated or amplified (“offset” controller) or the influence of the carrier signal (usually a spoken voice) to be limited … Read more
  • A-129 / 1 Vocoder Analysis & A-129 / 2 Vocoder Synthesis Section
    The vocoder modules are no longer manufactured. The Doepfer vocoder consists – sorry, consisted – of several modules. The two basic modules A-129/1 (analysis unit) and A-129/2 (synthesis unit or filter) were only available together. In the A-129 / 1 Analysis Section, the audio input signal is routed in parallel through 13 (steep) bandpass filters, … Read more
  • A-125 Voltage Controlled Phase Shifter
    Compared to the “Superphaser” A-101-3, the A-125 looks quite modest: Only half as many controls and – yes – 35 fewer sockets. But you don’t always need such complex options as the A-101-3 offers. Quite apart from the cost factor: You get 4 complete A-125 modules for the price of a single A-101-3. Oh yes: … Read more
  • 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-149-4 Quad Random Voltage Source
    The A-149-4 module is now the third member of the “A-149 family”. All three modules are about generating random voltages or trigger signals that go well beyond the possibilities of the random/noise modules A-118-1, A-118-2 or A-117. The A-149-1, which is based on the Buchla module 266, already has quantized voltages available that can be … Read more