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-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-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-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 / 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