A-110-6 Trapezoid Quadrature Thru Zero VCO

Compared to the A-110-4 Quadrature Thru Zero VCO, the A-110-6 has one more thing on top: We are not dealing with a sine core, but with a trapezoid core. This is a unique design that first creates a trapezoidal waveform, as well as a 90 degree phase-shifted trapezoid (the equivalents of the A-110-4‘s sine and … Read more

A-147-2 Voltage Controlled Delayed Low Frequency Oscillator

Compared to the rather unpretentious predecessor A-147, the new VCDLFO (Voltage Controlled Delayed LFO) is a monster. No fewer than 12 connection sockets on a module that is only 8 HP wide are already an announcement in terms of complexity in a confined space. In fact, Doepfer added a delay function to the voltage-controlled LFO … Read more

A-101-1 Vactrol Multitype Input VCF

The Vactrol filter has several special features. Most striking: There is a separate input for each of the operating modes lowpass, bandpass and highpass. This allows several very different sound sources to be treated differently in a single filter. Only the cutoff-frequency and the resonance (and resonance control) are common. If that’s too much for … Read more

A-168-1 PWM Generator

The A-168-1 is a small auxiliary module that generates a square or pulse oscillation that can be modulated in width for LFOs or VCOs without a square/pulse. This is an interesting feature for LFOs in particular, since almost all LFOs can generate a fixed, symmetrical square wave (at least the A-146 is capable of manually … 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-108 6/12/24/48dB Low Pass Filter

Like the A-120, the A-108 filter is also based on the Moog transistor cascade, but uses not only 4 poles, but 8 and can therefore have a maximum slope of 48 dB. That sounds sensational at first, but in real synthesizer life it’s not that extremely spectacular. What is striking, however, is the fantastic and … Read more

A-124 Wasp Filter

The Wasp Filter uses the somewhat idiosyncratic filter circuitry of the 1978 EDP Wasp synthesizer. The 12 dB filter produces very peculiar, “wild” distortions at higher resonances, which, however, always remain very easy to control. Possibilities and structure of the module (but not the layout of the front panel) are similar to the A-106-5 SEM … 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

A-188-1 BBD Module

The A-188-1A module (512 steps) is a discontinued model and will unfortunately no longer be produced in the future. Status: January 2023 BBDs – “Bucket Brigade Devices” are based on (analogue) storage components for voltages that are clocked through quickly by an internal oscillator. The voltage present at the input of the module is picked … Read more

A-110-4 Quadrature Thru Zero VCO

First of all: Wow, what a pompous name! “Quadrature Thru Zero VCO”! That sounds at least like Warp 11, quantum flux compensators and things like that, doesn’t it? The name is actually only topped by the A-110-6 “Trapezoid Thru Zero Quadrature VCO” – we’ll talk about that in a later blog post in this hyperspace … Read more