A-101-3 Modular 12 Stage Vactrol Phaser

The module is no longer in production. The A-101-3 phaser has two sub-units, each with 6 phase shifters (stages): The input signal runs through the 6 phase shifters connected in series and at the output, the original and the shifted signal can be mixed as desired using a “Mix” control. The output of the 6th … Read more

A-101-6 Opto FET Filter/Phaser

The Opto FET filter uses optical field effect transistors. That’s a statement you have to let sink in first. Maybe meditate on it too, it certainly won’t do any harm. Until then, very quietly, the question arises as to what on earth an optical field effect transistor could be and why you need something like … Read more

A-123-2 6/12/18/24 dB Highpass

After the Curtis chip CEM3320 was no longer available, Doepfer had to stop production of the A-123 24 dB highpass filter. It’s a pity, because there were simply no other 24 dB high-pass filters on the market! In the meantime, however, a replica is available with the AS3320, so that there is now a 24 … Read more

A-123 24dB High Pass

The module is no longer in production. Of all the modules that are no longer in production for one reason or another (most often it was the unavailability of certain Curtis chips, like the CEM3320 here), the A-123 filter was probably the most difficult to replace. There were simply no other 24dB high-pass filters, neither … Read more

A-141-2 Voltage Controlled Envelope Generator VCADSR / VCLFO

Pimp my VCADSR! The predecessor A-141 was a more than useful module for many purposes, but there were still “wishes” when it came to the details: The A-141 wasn’t as fast and “snappy” as the legendary A-140, and loopable envelopes like the A-143-1 or A-143-2 would sometimes be nice… With the new A-141-2, Doepfer has … Read more

A-142-2 Dual Envelope Controlled VCA

The module is small and interesting. A stripped down to two parameters but still flexible envelope generator with voltage control, hardwired to a linear VCA, plus a ducking function. The whole thing is also designed twice on only 8 HP. This is made possible by the new “Slim Line” format with slightly smaller buttons and … Read more

A-144 Morphing Controller

The module is no longer in production. The A-144 Morphing Controller generates control voltages that are used, for example, to regulate four linear VCAs of a voltage-controlled mixer in such a way that the four input signals of the mixer are morphed one after the other. The A-135-1 or A-135-2 Voltage Controlled Mixer and the … Read more

A-113 Subharmonic Generator

The Subharmonic Oscillator is a very unusual module that originated in Doepfer’s Trautonium project. Doepfer had implemented the necessary components of a Trautonium (a historical forerunner of today’s analog synthesizer by Friedrich Trautwein, 1888-1956) within the A-100 system. Unlike most other frequency dividers that output square wave signals, the A-113 produces sawtooth signals whose frequency … Read more