ADDAC System ADDAC102 (2023–)
A tiny Eurorack radio that turns static into signal, FM broadcasts into raw material, and your modular system into a wirelessly tuned chaos engine.
Overview
Patch a live FM radio into a 48-voice digital sequencer, trigger it with a triangle wave, and the whole thing collapses into a warbled commercial for car insurance. The ADDAC102 VC FM Radio brings the outside world into your rack, one half-caught pop song or burst of static at a time. It's not a sample player, not a synth, not even really an oscillator, though it can pass for all three. It's a receiver, used as a controlled breach.
Version 2 of the ADDAC102 has one important tweak: it's skiff-friendly. At just 5 cm deep, it fits into shallow cases without blocking adjacent modules. That matters in Eurorack, where depth often decides whether a module gets a home or sits in a drawer. The 8 HP width is compact, but not so cramped that the knobs feel like an afterthought. You'll be turning those knobs, even if you're using CV to automate them. Tuning through the dial and catching a snatch of talk radio before it dissolves into white noise is part of the appeal.
The module has a dual identity. It's a fully functional FM tuner, able to lock onto stations across the 87.5 to 108 MHz band (with firmware tweaks available for Japan's 76-96 MHz range). It also generates noise when no station is present, and for most modular users that's the more valuable half. The static isn't a digital simulation. It's the real hum and hiss of ambient RF energy, picked up through the included wire antenna, which plugs into a 2.5mm jack on the front panel. Think Wi-Fi routers, microwaves, distant taxi dispatchers and forgotten walkie-talkies. Because it's voltage-controlled, you can sweep through silence and signal with an LFO, jump between stations with gate triggers, or mute the output entirely with a logic signal.
Specifications
| Manufacturer | ADDAC System |
| Production Years | 2023– |
| Original Price | €315 |
| Format | Eurorack |
| Width | 8 HP |
| Depth | 5 cm |
| Power Supply | ±12V or ±15V |
| Current Draw | 100mA max |
| Bus Board Connector | 8×2 IDC (Doepfer style) |
| Frequency Range | 87.5–108 MHz (standard), 76–96 MHz (Japan firmware) |
| Channel Spacing | 100 kHz (EU), 200 kHz (US) |
| CV Input Range | ±10V |
| Gate Threshold | 2.5V |
| Outputs | Stereo audio (¼" jacks) |
| Antenna | External wire via 2.5mm jack |
| Mute Function | Hard mute via front panel button, soft mute via jumper setting |
| Seek Function | Seek Up/Down buttons for next station |
| Search Function | Search Up/Down adds ±0.1 MHz (EU) or ±0.2 MHz (US) |
| LED Indicators | Stereo output status, signal lock |
Key Features
Voltage-Controlled Tuning and Search
The ADDAC102 doesn't make you tune the radio by hand. The Tune knob sets the base frequency, and a CV input modulates it in real time, sweeping through the FM band with an LFO, sequencer, or random voltage source. To drift from a classical station into a burst of static and back every 16 steps, patch in a slow triangle wave. To jump between two stations based on a drum pattern, use gates to trigger the Seek Up/Down inputs. The Search Up/Down functions allow fine frequency adjustments of ±0.1 MHz (in EU mode) or ±0.2 MHz (in US mode), handy for nudging into a weak signal or scanning for hidden noise pockets.
Soft Mute Jumper and Noise as Feature
The soft mute jumper on the back of the PCB is one of the most telling design choices on the ADDAC102. By default, soft mute is off, so the module doesn't suppress output when no station is detected. That's intentional. ADDAC wants you to hear the noise. With soft mute ON, the radio behaves like a consumer device: quiet between stations, clean when locked. With it off, the static becomes a continuous, usable audio source, full of high-frequency detail and unpredictable transients. It's good for feeding filters, ring modulators, or granular processors. The jumper gives you a binary choice between raw and polished. Most users leave it off.
Regional Firmware and Customization
The standard firmware covers the European and North American FM bands. ADDAC also offers a special version for Japan (76-96 MHz), which must be requested at purchase. If the black front panel doesn't suit your rack, ADDAC will make a custom-colored one in red, green, blue, white, silver gray, yellowed silver, or bronze, with print options in black, white, or primary colors. The lead time is 4-6 weeks, and it's not cheap.
Historical Context
Radio has a long history in sound art, going back to Alvin Lucier's I Am Sitting in a Room and the BBC Radiophonic Workshop's tape manipulations. In modern Eurorack, the ADDAC102 fills a specific gap: digital oscillators and sequencers are precise, but they lack the unpredictability of the real world. Noise generators and sample players can simulate randomness, but they're still bounded by internal logic. The ADDAC102 doesn't generate randomness, it harvests it. It isn't the first radio module (Mutable Instruments' Elements had a radio-inspired mode, and some DIY kits exist), but it's the first commercially available Eurorack module to offer full voltage control over FM tuning, stereo output, and skiff-friendly packaging.
Collectibility & Value
The ADDAC102 is too new to be considered vintage in the traditional sense, but it already has a following in niche circles. It costs €315 new, which is steep for an 8 HP module. Used units trade for €250 - €280 depending on condition, with custom panels commanding small premiums. Failures are rare, since there are no moving parts and the circuit is straightforward. The 2.5mm antenna jack is delicate and can break if tugged. The module draws 100mA, which is moderate but worth watching in power-limited systems. No firmware updates or recalls have been reported, and ADDAC's support is responsive for regional firmware requests. When buying used, verify that the jumper settings match your region and that the CV inputs respond linearly. Some early units had minor calibration drift, though this is uncommon. If you want a stable, predictable oscillator, this isn't it.
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