ADDAC100 Series ()

Not a single synth, but a family of Eurorack oddballs—each one a tiny universe of noise, glitch, and raw voltage-driven surprise.

Overview

The ADDAC100 Series isn’t a product line so much as a cabinet of curiosities—modular experiments born in Lisbon, Portugal, by ADDAC System, each module chasing a different flavor of sonic mischief. These aren’t the polite oscillators or tidy filters that dominate Eurorack; they’re the ones you reach for when you want static, snare circuits gone feral, or a radio tuned to the hum of your power supply. They don’t pretend to be orchestras. They’re more like lab equipment left unattended for too long—patch them wrong, and you might summon something alive.

At the heart of the series is a love for repurposing circuits—taking something meant for one job and twisting it into another. The ADDAC103 T-Networks, for instance, draws inspiration from the twin T-networks found in classic drum machines, but instead of just making hi-hats, it turns into a cluster of chaotic, self-oscillating filters when fed audio. It’s 6HP of barely contained voltage chaos, with four voices split into high and low frequency ranges, and each input doubles as a gate-to-trigger converter—so you can sequence it, or just feed it noise and see what breaks. Owners report it’s as much a filter as it is a noise generator, especially when overdriven.

Then there’s the ADDAC105 4 Voice Cluster, an 8HP slab of square wave oscillation with a dark twist: all four voices route through a multimode filter with lowpass, bandpass, and highpass outputs. It’s not just additive—it’s a swarm you can shape, smear, or slice apart. The FM routing is particularly nasty in the best way: voice 1 gets modulated by voice 4, voice 2 by voice 1, and so on, creating a feedback loop of frequency chaos. There’s no 1V/octave calibration on the pitch CV inputs, which means tuning by ear—or not at all. That’s not a flaw, it’s a feature. It forces you into a looser, more experimental space.

Meanwhile, the ADDAC107 ACID Source started life as a drum module but became something else entirely—a full synth voice with a VCO, multimode filter, and VCA, all 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. But even here, ADDAC keeps things weird: the waveform mix lets you blend triangle, saw, and square, and the filter’s resonance can be pushed into self-oscillation. It draws 80mA on both rails—thirsty, but justified.

And then there’s the radio. The ADDAC102 VC FM Radio isn’t a sample player or 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. But the real magic is in the noise: when there’s no station, the static is rich with 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.” That’s not a side effect—it’s the point.

On the digital side, the ADDAC101 .Wav Player was one of ADDAC’s early hits, a no-frills SD card player that loads 22kHz 16-bit mono WAV files. It’s analog VCA, has an envelope follower CV output, and even a “Jumper Hack” on the back to introduce digital glitches when the sample rate switch is on. But it was limited—no loop points, no fine control. So they built the ADDAC111 Ultra .WAV Player: a full upgrade 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. It’s deeper, smarter, and still gloriously constrained by its format.

The ADDAC112 VC Looper & Granular Processor is the heavyweight—physically and conceptually. 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 not a DAW replacement—it’s a glitch box, a memory mangler, a way to turn a clean sample into something unrecognizable. And yes, it includes an SD card.

Rounding out the noise family is the ADDAC106 T-Noiseworks—also 8HP, also 4 voices, but 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, and it shows—this is where the concept peaks, with pre-VCA filtering on voices 1–3 and post-VCA on voice 4, creating 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 doesn’t just offer FM—it wires it 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 let you toggle this per voice, so you can isolate one link or let the whole thing run wild. There’s no index control—just on/off—so the modulation is either present or not, which keeps things aggressive. The square waves respond dramatically, turning simple sequences into metallic shrieks or pulsing drones. And because the entire cluster feeds a multimode filter with separate lowpass, bandpass, and highpass outputs, you can extract specific harmonics or let the full mess through. It’s a rare case where the lack of 1V/octave CV inputs isn’t a dealbreaker—this module isn’t for melodies, it’s for textures.

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—talk radio, music, 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 let you switch between EU and US tuning steps (0.1 or 0.2 MHz), or disable soft mute. But the real character comes from the gaps—the silence between stations, the bursts of interference, the way your modular case becomes part of the signal path. It’s not just a novelty; it’s a way to inject unpredictability, to let the outside world into your patches. And when no signal is present, the noise floor is rich and usable—perfect for drones or rhythmic static.

Noise Shaping in the ADDAC106 and ADDAC103

Both the ADDAC106 T-Noiseworks and ADDAC103 T-Networks are built around the same core idea: using T-networks to sculpt noise. But they diverge 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. And 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—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. But 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 even trigger the first eight files directly via the ADDAC111B expansion. It’s still limited to 72 files, but the workflow is vastly more musical. It’s not a sampler—it’s a precision tool for triggering and mangling short samples with modular control.

The Accidental Synth Voice: ADDAC107

The ADDAC107 ACID Source began as a drum module but became something else—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 there’s an Accent input to boost amplitude on command. What ties it together is the normalled CV output: it routes the envelope to both frequency and cutoff, so every trigger creates a pitch sweep and filter bloom by default. It’s expressive, immediate, and despite its name, 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 (240mA on +12V), deep, and not for the faint of heart. But for live mangling, glitch, or ambient textures, it’s a powerhouse.

Historical Context

The ADDAC100 Series emerged from ADDAC System’s penchant for circuit bending and repurposing. The ADDAC106 is explicitly noted as the final module in the T-Networks series, suggesting 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’s origin as a “lucky accident”—intended as a drum source but evolving into a synth voice—reveals ADDAC’s willingness to follow the circuit where it leads, rather than force a design. These modules aren’t chasing trends; they’re explorations.

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. However, 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 inclusion of SD cards and Micro USB ports introduces potential points of failure—card corruption, 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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