ADDAC 301 Floor Control (2013–2020)
A modest 4HP module for physical expression in modular. It can also power part of your case.
Overview
The ADDAC 301 Floor Control doesn't generate sound, shape it, or trigger it. It sits there and connects your feet to the patch. It's made for Eurorack systems where your hands are already tangled in cables and knobs, so it hands control to your feet: one stomp for sustain, one sweep of the heel-toe for real-time expression. There's a twist in the back end, too. It can supply +5V to your bus board, which makes it a power source for modules that need that third rail. In a system where every volt and HP counts, that perk can save you a rat's nest of adapters.
ADDAC released the 301 in 2013 as part of its 300 Series of interface modules. Eurorack was shifting from academic curiosity to live-performance instrument, and musicians were taking modular on stage. Pedal integration had become a necessity. The 301 kept it simple: two inputs (expression and sustain), two outputs (CV and gate), and a pair of trim controls that let you map the expression pedal's throw where you need it. No menus, no firmware, no OLED screens. Just knobs, jacks, and LEDs that blink in time with your footfalls.
It wasn't the first pedal interface for Eurorack, but it was among the first to balance utility, precision, and expandability. Competitors offered basic gate triggers or fixed-voltage expression inputs. The 301 let you adjust the CV range from ±10V and add an offset of ±5V. That means you could map a pedal sweep from 0V to 5V for filter cutoff, or -3V to +3V for vibrato depth, or invert the response for reverse sweeps. The dual-color LEDs (positive and negative) give immediate visual feedback, which helps when you're onstage under lights and can't see your scope. It uses a standard 6.3mm stereo jack for the expression pedal, so it works with nearly any off-the-shelf controller - Behringer FCV100, Moog EP-2, even Line 6 pedals if you're willing to mod the cable.
The sleeper feature is the +5V bus board adaptor. Modular systems running on ±12V often lack a dedicated +5V rail, and some digital modules (certain sequencers or clock dividers) require one. The 301 can provide up to 500mA on +5V, enough to power several low-draw modules, via a jumper on the back. Flip it, and your pedal interface is also a power hub. The catch is that if your case already has +5V, enabling this feature risks a short. The documentation warns you, but it's the kind of gotcha that has bitten more than one eager builder.
Specifications
| Manufacturer | ADDAC System |
| Production Years | 2013–2020 |
| Original Price | $90 USD |
| Form Factor | Eurorack |
| Width | 4 HP |
| Depth | 40 mm |
| Current Draw +12V | 20 mA |
| Current Draw -12V | 0 mA |
| Current Draw +5V | 0 mA (sinks up to 500mA when jumper enabled) |
| Bus Board Connector | 8-pin IDC (Doepfer style) |
| Expression Pedal Input | 6.3 mm stereo jack |
| CV Output Range | Adjustable ±10 V |
| Offset Control Range | ±5 V |
| Sustain Pedal Input | 6.3 mm mono jack |
| Gate Output | Positive trigger (LED monitored) |
| CV Output | Positive and inverted (±) |
| Indicators | LEDs for CV polarity and gate activity |
| Special Features | +5V bus board adaptor (jumper-enabled) |
Key Features
Expression with Surgical Precision
Most pedal interfaces in Eurorack treat expression bluntly: turn a knob, get a voltage, hope it lands where you want. The 301 handles it differently. The Range knob sets how much voltage swing your pedal produces, from a subtle ±1V wiggle to a full ±10V sweep. The Offset control shifts that entire range up or down by ±5V. Want your pedal to control resonance from 2V to 4V instead of 0V to 10V? You can. Need it to modulate pitch from -2V to +2V for a vibrato that doesn't jump octaves? You can do that too. The dual LEDs (one red, one green) show real-time polarity. Green brightens as the CV goes positive, red as it inverts. It's not a meter, but it's enough to tell if your pedal is tracking correctly or if the pot has drifted.
Sustain That Feels Like a Piano
The sustain input is designed to mimic the feel of a piano damper pedal. Plug in a standard momentary footswitch (like a Boss FS-5U), and the output sends a clean +5V gate when pressed. The LED pulses with each stomp, so you get visual confirmation even in dark setups. It doesn't support half-pedaling like high-end MIDI controllers, but the response is snappy and reliable. It works for holding down drones, freezing delays, or latching sequencers. In a live set, this single button lets you freeze a texture while you repatch or reach for another pedal.
The Hidden Power Node
Flip the module over and you'll find a tiny jumper that unlocks a feature no other pedal interface offered at the time: +5V output to the bus board. Most Eurorack cases provide only ±12V, but some modules, especially those with digital logic or microcontrollers, require +5V to run. Instead of adding a separate power distributor or modifying your PSU, the 301 can source up to 500mA on +5V. That's enough for several low-draw modules like clock utilities or logic gates. The jumper must be installed by hand on the back of the PCB, and the documentation warns against enabling it if your case already has +5V, as it could cause a short. For DIY builders or compact cases lacking that rail, it's a godsend. Don't forget it's there, though. Accidentally daisy-chaining to another +5V source could fry something.
Historical Context
When the ADDAC 301 launched in 2013, Eurorack was still shedding its image as a boutique curiosity. Modular wasn't yet the mainstream force it is today. Most players were tinkerers, academics, or experimental musicians patching in basements. Live performance was becoming a bigger focus, and the limits of hands-only control were obvious. Expression pedals and footswitches were standard on keyboards and guitar effects, but modular lagged behind. Companies like Intellijel and Doepfer offered basic gate interfaces, but few gave performers real control over CV mapping.
ADDAC, a Portuguese boutique known for clean design and utility modules, saw the gap. The 301 was part of their 300 Series, which was dedicated interface tools rather than sound generators. It arrived just as performers like Kim Bost and Hainbach were demonstrating that modular could be dynamic and physical. A pedal to control filter sweeps, delay feedback, or sample position was suddenly essential. The 301 was reliable, precise, and affordable. At $90, it was half the price of some competing solutions, which made it accessible to players building their first case.
It also arrived before the Eurorack gold rush of the mid-2010s, when prices inflated and modules became collectible. The 301 stayed in production until around 2020, when ADDAC shifted focus to more complex systems. It never got a "Mark II."
Collectibility & Value
The ADDAC 301 Floor Control isn't a collector's grail. On the used market, it typically sells for $80 - $120, depending on condition and whether it includes the original box and jumper. Units described as "mint, never used" occasionally fetch $130, but that's rare. Unlike rare oscillators or vintage filters, the 301 isn't hoarded. It's used, passed on, or sold when a player upgrades. That keeps supply steady and prices reasonable.
Condition-wise, it's a sturdy module. There are no moving parts on the PCB, and the jacks are standard Neutrik types that can be replaced if worn. The main failure points are user errors: enabling the +5V jumper in a case that already has +5V (which can damage the PSU or other modules), or using a damaged expression pedal cable that shorts the stereo jack. The trim pots for Range and Offset can drift over time, especially if over-tightened, but recalibration is straightforward with a multimeter.
When buying used, check that the LEDs respond correctly, with no flickering or dimness, and that the CV output tracks smoothly across the pedal's range. Test both the positive and inverted CV outputs with a voltmeter or connected module. Inspect the back for the +5V jumper. If it's installed, confirm with the seller whether their case used it, and make sure your own setup can handle it. A unit with the jumper removed is safer for most modern cases.
Restoration is minimal—no recap needed, no firmware updates, no alignment. If the front panel is scratched, replacements are available from third-party vendors, but the original black anodized aluminum holds up well. Given its utility, the 301 is more likely to be retired due to obsolescence (if a player moves to a pedal interface with MIDI or multiple zones) than failure. But for anyone still running a classic Eurorack case, especially one lacking +5V, it remains a smart, functional addition.
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