Measures the time between pulses entered and plays back a sequence of pulses. These can be either the base frequency or a multiple of it. Own design based on an Atmega8 microcontroller.

Basic Analog Sequencer with two CV lanes and one Gate lane. CV-controllable Start and Reset function. This is a design of my own based on discrete CMOS logics components.

The clock divider provides the 1/2 up to 1/64 of the input clock. The multiplexer on the right side routes one channel to 8 options depending on the selection made. The selection made using three input, each representing one bit. Own design, basically wiring up some CMOS multiplexer and counters.

Great for rhythmic patches and visualizing binary counting, there are many LED’s in this module.

Basically and integrator in a mathmatical sense, useful to smooth out the control voltages generated by the sequencer or to generate a glide effect when the pitch CV of a keyboard is processed through it.

See A-137 Got this one second hand at a synth gathering. Easily converts boring waveform into chaotic and dirty sounds.

Provides CV Clock given Midi Clock. Own design, uses an Atmega8 or similar to receive and convert the midi clock information.

A Delay effect based on the well-known PT2399 IC used in a plethora of audio equipment. Delay time can to some extent be CV-Controlled, also the feedback path has an insert to add other effects such as filters into the delay path. Own design.

A fairly complex phase built around eight CV-controllable analog allpass modules. Input and Output of the feedback  path can be chosen by the two rotary switches on the right. Can produce everything from subtle phasing to self-oscillations. Own design, though heavily influences from phaser designs on the internet.

The most useless module so far. This either generates static control voltages whose values are visible on the displays (which are way too dark..) or measures the voltage applied at the input. Own design, uses Atmega8’s to measure the control voltages. I remember have done the firmware for the Atmega’s in assembly, at least I learned how conversion to BCD (binary coded digits) works 😉

A Ringmodulator with a well-known AD633 IC at its core. Own design heavily inspired by existing AD633-based Ringmods.

With this module the DIY eurorack modular adventure started. Since it already built a drum synthesizer (see https://makingofadrumsynth.blogspot.com/ ) i already has some skills to tackle a fairly complex module. This module pushed an atmega16 to its boundaries by programming a polyphonic midi-controlled synth onto it. It has a ADSR Envelope, a 1-pole lowpass filter, a quantizer and wavetable oscillator with a voltage controllable index.

The wavetable has been filled with various self-recorded vowels, aliasing is a feature. This module can generate some dirty oldschool pad sounds and warbling wavetable sounds. Own design.

The first real analog module. One to one copy of https://doepfer.de/a110_tec.htm. Building and calibrating was the challenge here.

The filter which is a must in every synth, as far as i remember this is taken from Music from outer space.

A little audio mixer, usually the last module in a patch. The phase can be inverted for every channel. This idea behind this was to turn the lowpass into a highpass by subtracting the lowpass signal from the original. This has proven to work in theory an when tweaking very carefully. Own Design.

Dual linear VCA, Schematic taken from https://musicfromouterspace.com/index.php?MAINTAB=SYNTHDIY&VPW=1840&VPH=809.

A class ADSR Envelope, the design is heavily influenced by https://musicfromouterspace.com/index.php?MAINTAB=SYNTHDIY&VPW=1840&VPH=809. A more or less identical copy is further right in the same row.

A simple an a voltage controlled LFO, both inspired by various design from Music From Outer Space.

Utility module which buffers and distributes a signal. It seems i was a bit obsessed with phase inversion by the time i built this synth.

A Noise Oscillator and a Sample&Hold circuit combined in a module. Has an internal clock but also accept clock input. I mostly use this for random CV steps. Own design

Great module to actually play a patch. See https://doepfer.de/a174.htm for reference.

A Steiner Parker Filter. The first module i built/fixed from a kit i got for free but was broken.

The remaining space of this rack was filled up with with a module with allowed to connect an electric guitar to the modular system.

Another 24dB/Oct Lowpass, this time implemented as a ladder filter. As far as i remember the design is this: https://electro-music.com/wiki/pmwiki.php?n=Schematics.DiodeLadderVCF. The only filter in the synth with voltage controllable resonance.

A logarithmic VCA, inspired by https://musicfromouterspace.com/index.php?MAINTAB=SYNTHDIY&PROJARG=ALIENSCREAMER/ALIENSCREAMER.php&VPW=1670&VPH=790.

Doepfer A-140 ADSR Envelope Generator. This one ca also generate very short envelope, this is not possibly with the DIY Envelope generator in the rack below this one.

a simple Doepfer linear VCA. One can never have enough VCA’s in a modular synth. Since i already built one i decided to buy an additional VCA this time since building the same thing again isn’t really interesting.

This percussive voice module has been built from an ordered pcb, which is rare. Most of the modules have been built using perfboard. It is taken from https://www.birthofasynth.com/Thomas_Henry/Pages/MPS_project.html.

Generates pulses of definable width given an input signal. The width of the output pulse can be set differently for the falling and rising edges if the input pulse. I have no memories from where i got this module and why it built it. The german labels don’t help either.

A LoFi Looper/Sampler. I got this on a trip to berlin when visiting famous https://schneidersladen.de/. Always fun to use though very unpredictable.

Compresses an input signal and extracts the envelope. This module is designed specifically to process electric guitar or other non-electronic instruments through the modular system. Own design,

A Reverb Module built around the FV-1 DSP IC. This module has been added after a long break in building synth modules. It is the first module with a self-designed PCB.

Draws no power, emits or processes no sounds. Available for sale 😉