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-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

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-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-127BOM Breakout Module

The module is no longer in production. The A-127 BOM is an extension for the A-127 Triple Resonance Filter. It supplements the module with individual inputs for each of the three filters, as well as separate outputs (per filter) for bandpass, highpass, lowpass and notch. The original A-127, on the other hand, only offered a … 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-126 Voltage Controlled Frequency Shifter

The module is no longer in production. Unfortunately, the VC Frequency Shifter is no longer available because one of the components used is no longer manufactured. In principle, however, the task of the missing component could be taken over by an A-143-9 Quadrature LFO or an A-110-4 Quadrature Thru Zero VCO, so that this particular … Read more

A-167 Analog Comparator / Subtractor / Offset Generator

The module is no longer in production. The A-167 Analog Comparator can compare voltages with each other and generate a gate signal. There are many possibilities: comparison of two external voltages, comparison of a voltage (normal or inverted) with a positive or negative threshold value, comparison of the difference between two external voltages with a … Read more

A-172 Maximum / Minimum Selector / Rectifier

The module is no longer in production. The A-172 maximum/minimum selector leaves many “modularists” at a loss at first. A module that selects and makes available both the maximum and the minimum voltage from up to four input signals may appear too “mathematical” or intricate. In fact, the module is a surprisingly easy-to-use tool for … Read more