ADDAC 507 Random Bezier Waves

Two channels of smooth, organic randomness that feel alive—like an LFO dreamed by a mathematician who loves curves.

Overview

If your modular rig feels too predictable, the ADDAC 507 Random Bezier Waves is the quiet chaos agent you didn’t know you needed. It’s not about jagged jumps or binary noise—it’s about motion, flow, and the kind of slow-burning unpredictability that makes a patch breathe. This Eurorack module gives you two fully independent channels of smoothed random control voltages, each generating bipolar voltages that glide between points using Bezier curve interpolation. That’s the secret sauce: instead of linear ramps or stepped jumps, you get curves that feel natural, almost biological. The result? Modulation that doesn’t just change—it evolves.

Built as a two-channel modulation source, the 507 sits in that sweet spot between an LFO and a random voltage generator, blurring the line until it’s hard to tell which is which. It’s not just random; it’s *shaped* randomness. And because both channels are identical and deeply interconnected, you can create feedback loops, cross-modulate parameters, or average their outputs for even more nuanced behavior—all without patching a single cable beyond your power bus. It’s the kind of module that rewards exploration but delivers usable results even with the most basic setup.

It whispers, drifts, pulses, and folds—adding life without demanding attention.

Specifications

Key Features

Smooth Random Generation with Bezier Curves

Each channel on the ADDAC 507 is a complete smooth random voltage generator. The magic happens in the interpolation: instead of jumping or ramping linearly between random points, it uses Bezier curves to create flowing, organic transitions. The “Curve” parameter lets you adjust the shape of this interpolation, giving you control over how the voltage moves from point to point—whether it’s a gentle arc or something more dramatic. This is what gives the module its distinctive character: the voltages don’t just change, they *move* with intention.

Interconnected Dual Channels

The two channels aren’t just side-by-side—they’re designed to talk to each other. When you leave the CV inputs for Frequency and Level unpatched, they’re internally connected to the main output of the opposite channel. That means Channel A can modulate Channel B’s speed and amplitude, and vice versa, creating self-generating, evolving feedback patches right out of the box. It’s a small detail that opens up entire worlds of generative patching without needing external modulation sources.

Smart Gate Outputs with Different Personalities

The gate outputs on each channel aren’t identical twins—they’re siblings with different temperaments. Channel A’s gate fires a pulse every time a new random value is generated, making it perfect for triggering envelopes or sequencing events in time with the voltage shifts. Channel B, however, acts like a comparator: it outputs a high gate whenever its main output is positive. This lets you create rhythmic patterns based on the waveform’s polarity, turning smooth voltage changes into dynamic, responsive triggers.

Flexible Output Options and Visual Feedback

Beyond the main and inverted wave outputs per channel, the module includes two summed outputs: AB Average and Inverted Average. These let you blend the two channels into a single, more complex control voltage—ideal for modulating a filter cutoff or pitch with a composite signal. And because the module features LED displays for both bipolar activity and gate behavior, you can actually *see* the randomness unfolding in real time. It’s not just functional—it’s hypnotic.

Offset, Attenuation, and Signal Shaping

Each channel offers an Offset control that shifts the entire voltage range up or down within a ±5V window, letting you align the random signal with the needs of your destination module. The Level control doubles as an attenuator and VCA, allowing you to scale the output from full amplitude down to silence. Combined with CV inputs for both Frequency and Level—each with their own attenuators—you get deep real-time control over the module’s behavior, whether you’re modulating it externally or letting it run wild on its own.

Historical Context

The ADDAC 507 Random Bezier Waves began as an idea from Rijnder Kamerbeek, better known in the modular world as Monotrail—a respected YouTuber and modular enthusiast. His vision was simple: a straightforward random generator that interpolates between points using smooth curves, effectively functioning as a complex, ever-evolving LFO. That concept became the foundation of the module, which was then realized by ADDAC System as part of their ADDAC500 Series. While no broader historical context or market timing has been documented beyond this collaboration, the module stands as a modern example of community-driven design in the Eurorack ecosystem—where end users help shape the tools they want to see.

Collectibility & Value

The ADDAC 507 is currently available new from retailers at €245.08 (excluding VAT), making it a mid-tier investment for Eurorack users. While no original MSRP or production years have been confirmed, its current pricing reflects its niche appeal and specialized function. There is no documented data on common failures, maintenance issues, or long-term reliability— Collectibility is currently driven more by utility than scarcity; this isn’t a grail module, but it’s one that tends to stay patched in once installed.

One user review captures the sentiment well: “Slow Random Voltages kann man sich auch selbst basteln… oder man benutzt ADDAC 507 Random Bezier Waves. Zwei, drei schnelle Einstellungen und der Käse ist gelutscht.” (Translation: “You can build slow random voltages yourself… or you just use the ADDAC 507. A couple quick settings and the job’s done.”) The reviewer goes on to say the Bezier interpolation produces “weichere Übergänge” (softer transitions) than traditional methods, concluding: “Wer leistungslos bessere Ergebnisse erzielen will, als mit viel Fummelei, ist hier bestens bedient. Ich liebe das Teil.” (“If you want better results with less effort, you’re in good hands here. I love this thing.”) That kind of endorsement—practical, enthusiastic, and slightly smug—says more than any spec sheet ever could.

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