ADDAC100 Series ()

Not a single synth, but a family of Eurorack oddballs. Each one is a small box of noise, glitch and voltage-driven surprise.

Overview

The ADDAC100 Series is a set of modular experiments from ADDAC System in Lisbon, Portugal. Each module chases a different kind of sonic mischief. These aren't the polite oscillators or tidy filters that fill most Eurorack cases. They're for static, snare circuits gone feral, or a radio tuned to the hum of your power supply. They don't pretend to be orchestras. Patch them wrong and you might get something that sounds alive.

The series is built on repurposing circuits, taking something meant for one job and bending it into another. The ADDAC103 T-Networks draws on the twin T-networks found in classic drum machines. It makes hi-hats, but fed audio it turns into a cluster of chaotic, self-oscillating filters. It's 6HP, with four voices split into high and low frequency ranges, and each input doubles as a gate-to-trigger converter. You can sequence it, or feed it noise and see what breaks. Owners report it's as much a filter as it is a noise generator, especially when overdriven.

The ADDAC105 4 Voice Cluster is an 8HP slab of square wave oscillation. All four voices route through a multimode filter with lowpass, bandpass and highpass outputs. The FM routing is nasty in the best way: voice 1 gets modulated by voice 4, voice 2 by voice 1, and so on, which makes a feedback loop. There's no 1V/octave calibration on the pitch CV inputs, so tuning is by ear, or not at all. That's a feature, and it pushes you toward looser, more experimental patches.

The ADDAC107 ACID Source started life as a drum module and became a full synth voice. It has a VCO, multimode filter and VCA, chained together with an AD envelope and accent input. It's one of the more "musical" modules in the lineup, with 1V/oct sample rate control and CV normalled to both frequency and cutoff. It's still odd, though. The waveform mix blends triangle, saw and square, and the filter's resonance can be pushed into self-oscillation. It draws 80mA on both rails.

The ADDAC102 VC FM Radio isn't a sample player or a synth. It's an actual FM radio tuner in Eurorack format, with a 2.5mm jack for an external wire antenna. It tunes between 87.5 and 108 MHz (or 76-96 MHz with Japanese firmware), and has jumpers to select EU or US step sizes (0.1 or 0.2 MHz). It's stereo, with an LED to show signal lock, and the CV inputs go up to ±10V. With no station, the static is full of electromagnetic artifacts: tape hiss from nearby gear, digital whines, the hum of your laptop. As the product page says, "you can also have a lot of fun with the fact that it's a great noise generator."

On the digital side, the ADDAC101 .Wav Player was one of ADDAC's early hits. It's a no-frills SD card player that loads 22kHz 16-bit mono WAV files. It has an analog VCA, an envelope follower CV output, and a "Jumper Hack" on the back that introduces digital glitches when the sample rate switch is on. It was limited, with no loop points and no fine control. So they built the ADDAC111 Ultra .WAV Player, with bipolar CV, 1V/oct sample rate, loop start/size controls, and external state switching. It supports up to 72 files, named simply a.wav, b.wav, etc., and has an expansion module (ADDAC111B) for triggering the first eight directly.

The ADDAC112 VC Looper & Granular Processor is the heavyweight. At 32HP + 13HP, it's two modules in one, with a Micro USB port between the PCBs for firmware or file transfer. It can record up to 3 minutes of stereo audio at 44.1kHz (24-bit in firmware 1.9), with a buffer up to 5 minutes. It splits into Looper and Granular engines, with a simple menu for loading and saving banks. It's a glitch box, not a DAW replacement. And it includes an SD card.

The ADDAC106 T-Noiseworks is also 8HP and also 4 voices, but it's focused entirely on noise shaping. Each voice has frequency and decay controls, and a timbre switch: Hat or Snare. In Hat mode, a high-pass cuts the lows. In Snare, everything passes. Voice 4 has a frequency range switch (Low/Mod/High), and the summing mix offers a "Dirt" output for extra grit. It's the last in the T-Networks series, with pre-VCA filtering on voices 1-3 and post-VCA on voice 4, which gives different response curves. It's not subtle, but it's punchy, and the slew on the trigger input gives each hit a natural decay.

Specifications

Key Features

The FM Feedback Loop in the ADDAC105

The ADDAC105 4 Voice Cluster wires its FM into a loop. Each voice's FM input comes from the previous voice, with voice 1 fed by voice 4, closing the chain. The [FM ON] switches toggle this per voice, so you can isolate one link or let the whole thing run. There's no index control, just on/off, so the modulation is either present or not. The square waves respond dramatically, turning simple sequences into metallic shrieks or pulsing drones. The whole cluster feeds a multimode filter with separate lowpass, bandpass and highpass outputs, so you can pull out specific harmonics or let everything through. The lack of 1V/octave CV inputs isn't a dealbreaker here, since this module is for textures, not melodies.

Radio as Instrument: The ADDAC102

The ADDAC102 VC FM Radio treats broadcast signals as raw material. With a simple wire antenna plugged into the 2.5mm jack, it pulls in whatever's nearby, like talk radio, music or static, and outputs it in stereo. The CV inputs go up to ±10V, so you can sweep across the band with a slow LFO or jump stations with a sequencer. The two jumpers on the back switch between EU and US tuning steps (0.1 or 0.2 MHz), or disable soft mute. The gaps are part of the sound: the silence between stations, the bursts of interference, your modular case becoming part of the signal path. When no signal is present, the noise floor is rich and usable for drones or rhythmic static.

Noise Shaping in the ADDAC106 and ADDAC103

The ADDAC106 T-Noiseworks and ADDAC103 T-Networks are built around the same idea, using T-networks to sculpt noise. They differ in execution. The ADDAC103 has four voices with frequency and decay controls, and the top two channels are tuned higher than the bottom two. Each input can accept gate or audio, and when fed audio, the voices act as "very destructive filters," meaning they can mangle a clean signal into something gritty and unstable. The ADDAC106 refines this. Voices 1-3 have pre-VCA filtering, so the envelope shapes the filtered signal, while voice 4 filters post-VCA, letting the full envelope pass before coloring. The timbre switch (Hat/Snare) on voices 1-3 adds a high-pass in Hat mode, thinning the sound. Voice 4's frequency range switch (Low/Mod/High) changes its response dramatically. The summing mix offers a "Dirt" option, likely a soft clip or overdrive, for extra saturation.

Digital Playback Evolved: From ADDAC101 to ADDAC111

The ADDAC101 .Wav Player was a minimalist take on sample playback. You load 22kHz mono WAVs onto an SD card, trigger them, and shape them with an analog VCA. It had an envelope follower CV output, useful for ducking or modulation, and a hidden "Jumper Hack" to add digital artifacts. It lacked loop control and fine CV shaping. The ADDAC111 Ultra .WAV Player fixes that. It keeps the same file format (22.05kHz mono WAVs, named a.wav to 9.wav) but adds bipolar CV inputs, 1V/oct sample rate (from -4 to +1 octave), and dedicated loop point controls. You can set start and size with CV, switch between one-shot and loop modes, and trigger the first eight files directly via the ADDAC111B expansion. It's still limited to 72 files. It's not a sampler, but a tool for triggering and mangling short samples with modular control.

The Accidental Synth Voice: ADDAC107

The ADDAC107 ACID Source began as a drum module and became a full synth voice, with a VCO, filter and VCA in one 9HP unit. The VCO offers triangle, saw and square waves, with a switch to mix the triangle/saw blend against the square. The filter has cutoff, resonance, and a 3-way switch for highpass, bandpass or lowpass. The VCA is fed by an AD envelope with decay control and CV input, and an Accent input boosts amplitude on command. The normalled CV output routes the envelope to both frequency and cutoff, so every trigger makes a pitch sweep and filter bloom by default. Despite its name, it's not particularly "acid," but it can get close with resonance cranked and square wave mixed in.

Looping and Granular Chaos: ADDAC112

The ADDAC112 VC Looper & Granular Processor is the most complex module in the series. It's physically split into two PCBs with a Micro USB port between them, likely for firmware updates or direct file access. The Looper Engine can record up to 3 minutes of stereo audio (44.1kHz, 24-bit in firmware 1.9), with a 5-minute buffer. The Granular Engine lets you slice and manipulate the buffer, while the Output Mix section blends the results. There's a simple menu system for loading and saving banks, but no touchscreen or encoder, just buttons and LEDs. It includes an SD card, so you can preload samples or save recordings. It's power-hungry at 240mA on +12V, and deep.

Historical Context

The ADDAC100 Series came out of ADDAC System's habit of circuit bending and repurposing. The ADDAC106 is explicitly noted as the final module in the T-Networks series, which suggests a deliberate arc from the ADDAC103's drum machine inspiration to the ADDAC106's refined noise architecture. The ADDAC111 was developed as a direct response to user feedback on the ADDAC101, which the manufacturer calls "one of our bestsellers," indicating strong adoption. The ADDAC107 started as a "lucky accident," intended as a drum source but evolving into a synth voice.

Collectibility & Value

Original pricing ranged from 110.00 € for the ADDAC103 to 620€ for the ADDAC112, with mid-tier modules like the ADDAC107 at 210€ and the ADDAC102 at 315.00 €. There is no current market data on resale value, condition issues, or common failures in the fact sheet. The ADDAC101's status as a bestseller suggests it may be more commonly found, while the ADDAC112's complexity and size might make it rarer in the wild. The SD cards and Micro USB ports are potential points of failure, such as card corruption or port damage, but without failure reports this remains speculative. Maintenance advice and long-term reliability are not documented in the source material.

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