ADDAC 301 (2014–present)

Four HP of freedom: plug in your old expression pedal, free your hands, and finally stop chewing cables mid-performance.

Overview

It starts with the tangle—patch cables knotted around your forearm, one hand twisted behind your back trying to reach a hidden attenuator, the other wrestling with a sequencer that just won’t sync, and your foot tapping uselessly on the floor like it’s got nothing better to do. Then you remember that dusty expression pedal buried in the bottom of your gear case, the one you used with your old keyboard rig back in 2008. That’s when the ADDAC 301 clicks: a small, red, 4 HP module that doesn’t make sound, doesn’t generate sequences, but gives your feet a voice in the modular conversation. It’s not flashy, but it’s transformative—like discovering your synth has a back door you never knew existed.

Launched in early 2014 as part of ADDAC’s 300 Series of expressive control modules, the 301 Floor Control was built for one purpose: to let you use standard expression and sustain pedals in a Eurorack system without fuss. That might sound simple, but in the world of modular, simplicity with reliability is rare. Most expression solutions require voltage scaling, offset adjustments, or external power supplies just to get a pedal to sweep a filter smoothly. The 301 does it all in one compact module, with tactile knobs, visual feedback via LEDs, and a clever +5V bus board adaptor that doubles as a small utility fix for power-starved skiffs. It doesn’t try to be everything—no MIDI, no digital processing, no hidden modes. It’s a clean, analog-friendly interface that just works, and that’s why it’s lasted.

Positioned as a utility controller rather than a sound module, the 301 sits below ADDAC’s more complex offerings like the 303 Muscle Sensing or the 714 Vintage Clip. But don’t mistake its simplicity for being entry-level—it’s more like the Swiss Army knife of foot control: compact, reliable, and always useful. While the 301B Dual Expression Attenuator and 301C Dual Sustain Switcher offer passive alternatives, the 301 is the only one in the series with active CV processing, LED monitoring, and offset/range control, making it the centerpiece of ADDAC’s expressive control lineup. It’s not the flashiest module on your rack, but it’s often the one you reach for first when you want real-time, hands-free modulation.

Specifications

Manufacturer	ADDAC System
Production Years	2014–present
Original Price	€70
Width	4 HP
Depth	40 mm (4 cm)
Current Draw	20 mA (+12V), 0 mA (-12V), 0 mA (+5V)
Bus Board Cable	8 × 2 IDC (Doepfer style)
Expression Pedal Input	6.3 mm (1/4") stereo jack
CV Output Range	Adjustable from -10 V to +10 V
Offset Control Range	±5 V
Sustain Pedal Input	6.3 mm (1/4") mono jack
Gate Output	1 V to 10 V (normalized to +10 V)
CV Outputs	Positive and inverted
LED Indicators	CV positive, CV negative, gate output
+5V Bus Board Adaptor	Yes (jumper-removable)
Compatibility	Standard stereo expression pedals (e.g., Moog EP-2, Behringer FCV100); mono expression pedals require modification

Key Features

Expression Control with Precision

The heart of the 301 is its expression pedal input, which accepts any standard stereo 1/4" expression pedal—no adapters, no soldering (unless you’re using a mono pedal, which requires a simple mod). What sets it apart is the pair of front-panel knobs: Range and Offset. The Range knob lets you scale the full travel of your pedal from a narrow ±1 V sweep to the full Eurorack ±10 V range. This is critical—some modules respond dramatically to small CV changes, while others need a full 10 V to open up. Being able to dial in the exact range means you can go from subtle filter nudges to full-on oscillator sweeps without overshooting. The Offset knob then shifts that entire range up or down by ±5 V, so you can start a sweep from zero, or bias it into positive territory for exponential responses. It’s rare to find this level of control in such a small module, and rarer still for it to be this intuitive.

Visual Feedback That Actually Helps

Two small LEDs—labeled “+” and “–”—track the polarity of the CV output in real time. When your pedal sweeps into positive voltage, the “+” LED glows; when it dips negative, the “–” lights up. It’s a small detail, but it eliminates guesswork. If you’re modulating a VCA and the sound cuts out at the heel position, a quick glance tells you whether you’ve accidentally dipped into negative voltage where the VCA won’t respond. The gate output for the sustain pedal also has its own LED, so you can see at a glance whether the pedal is registering as “on” or “off.” In a dark studio or on a dimly lit stage, that kind of feedback is invaluable.

Hidden Power Utility: The +5V Adaptor

Tucked away on the back of the module is a jumper that enables a +5V bus board adaptor. When activated, the 301 can supply +5V power to any compatible bus board, which is especially useful in skiff setups where the main power supply might not include +5V rails. This wasn’t just a convenience—it addressed a real gap in early Eurorack power distribution, where many modules (especially digital ones) began requiring +5V but not all power systems provided it. While newer power solutions have largely caught up, this feature still makes the 301 a stealth upgrade for older or minimalist cases. The fact that it can be disabled via jumper means you’re not forcing +5V where it’s not needed, avoiding potential conflicts.

Historical Context

The ADDAC 301 arrived in 2014, right as Eurorack was shifting from niche hobbyist curiosity to mainstream modular adoption. At the time, many players were coming from traditional keyboard rigs, bringing with them expression pedals they didn’t know how to use in modular. Most solutions were either DIY builds, clunky external converters, or expensive MIDI-to-CV boxes. The 301 filled that gap with a no-nonsense, Eurorack-native answer. It wasn’t the first foot controller for modular—Intellijel’s Touché and Livewire’s Variable Mu had already explored expressive control—but it was among the first to make it accessible, affordable, and rack-efficient.

ADDAC, based in Lisbon, had already built a reputation for thoughtful, musician-first design with modules like the 008 Quad LFO and the 101 Digital Noise Generator. The 300 Series, including the 301, was a deliberate pivot toward performance and tactile control, recognizing that modular wasn’t just for patching in silence—it was for playing. Competitors like Doepfer and Analogue Solutions offered basic pedal inputs, but few provided the same level of voltage control and feedback. The 301 didn’t try to reinvent expression; it just made it finally practical.

Collectibility & Value

The ADDAC 301 has never been a “hype” module, but it’s quietly become a staple. It’s not rare—production has remained steady since 2014—and it’s not discontinued, so there’s no artificial scarcity. But its value lies in its utility, not its rarity. On the used market, prices range from $75 to $110 depending on condition and region. Units in full working order with clean jacks and responsive knobs typically sell in the $85–$95 range, while those with worn labels or stiff potentiometers go for less. Because it’s a passive interface with minimal internal circuitry, failure rates are low, but the most common issues stem from the input jacks—especially if users frequently plug and unplug pedals. Oxidation or loose solder joints can cause intermittent signal, so it’s wise to check both expression and sustain inputs before buying.

The +5V adaptor feature, while useful, can be a double-edged sword. If the jumper is left enabled in a system that already supplies +5V, it can cause power conflicts or even damage sensitive modules. Service technicians observe that many users aren’t aware of the jumper’s function, so it’s worth verifying its position when buying used. Otherwise, maintenance is minimal—no firmware, no moving parts beyond the knobs, and no calibration needed. For long-term owners, the only real wear point is the expression pedal jack, which sees the most use. Cleaning with contact cleaner and gentle reseating of cables usually resolves most issues.

If you’re building a performance-oriented rack, the 301 is a no-brainer. It’s not the kind of module that makes you say “wow” when you power it on, but it’s the one that makes everything else easier. For players coming from hardware synths or DAWs, it bridges the muscle memory gap—finally letting you use your feet like you would on a piano or guitar rig. And for those on a budget, it’s one of the few ADDAC modules that hasn’t appreciated significantly in price, making it an accessible entry point into the brand’s ecosystem.