ADDAC System 705 Dual Noise (2010s)

Two analog noise sources in a 6HP slot - white, pink, or a blend, all from discrete circuitry.

Overview

The ADDAC 705 is a pair of discrete analog noise sources wired side by side, each with its own control. It isn't a digital generator faking randomness with algorithms. One channel gives full-spectrum white noise. The other gives pink noise, heavier in the low mids, with the highs tapering off naturally. A toggle blends the two for something in between. In a Eurorack system where so much is digitally generated or quantized, this is a plain analog hiss source.

At first glance, it might seem like just another utility module—noise is noise, right? But the 705 earns its keep not by being flashy, but by being essential. Need to modulate a filter for a lifelike cymbal hit? White noise here. Simulating ocean waves or wind with a slow LFO on a VCA? Pink’s your friend. Want to patch into a sample-and-hold for stepped randomness that doesn’t sound clinical? The 705 feeds that circuit with organic grit, the kind that feels like it came from the real world, not a microprocessor. And because both channels are normalized, you can run one output while keeping the other patched and ready—no need to repatch just to swap textures. The module doesn’t try to do everything; it does one thing, and it does it with a purity that’s rare in modular systems today.

It’s also a quiet workhorse in design. The black anodized panel is clean, minimal—no flashy graphics, no unnecessary labels. Just two outputs per channel, a toggle switch per side, and a master bypass. It doesn’t scream for attention, but when you need it, it’s always ready. And at 6HP, it’s skiff-friendly, the kind of module you can justify adding even when your case is packed. You don’t buy the 705 because it’s novel; you buy it because after a while, you realize you’re tired of the sterile, quantized randomness of digital noise sources. You want something that breathes. Something that sounds like it’s alive.

Specifications

Key Features

Analog Noise Generation via Discrete Circuitry

The 705 is fully analog and discrete - no microcontrollers, no digital signal processing, just transistors and resistors generating the noise. That affects the sound. Digital noise sources can feel too even, lacking the small irregularities that make analog noise feel "real." The 705's white noise has a slight grain to it, and it responds dynamically when fed into filters or VCAs. The pink noise rolls off naturally above 1kHz, which avoids the fizzy top end that can make some digital pink noise feel artificial. Both are generated independently, so you can use them at the same time without crosstalk or phase issues. That matters for complex modulation or stereo processing.

Flexible Channel Toggling and Normalization

Each channel has a three-position toggle: white, pink, or blend. The blend isn't a fixed mix. It's a passive resistor-based combination that leans slightly toward white but keeps enough low-end warmth for textured sweeps or evolving drones. The outputs are normalized, so if you only use the left output of a channel, the right one still carries the same signal. In practice, that means you can send one channel to a filter for a snare sound and patch the same output to a reverb for ambience, with no mult needed.

Compact and Skiff-Friendly Design

In a format where every HP counts, the 705’s 6HP footprint is a win. It doesn’t demand attention, doesn’t hog space, but delivers functionality that larger modules sometimes miss. At 40mm deep, it fits comfortably in most skiffs and travel cases, making it a favorite among touring modular performers who need reliable noise sources without the bulk. The black panel and clean layout ensure it blends into any system, but the tactile switches and clearly labeled outputs make it easy to use even in low-light environments. It’s the kind of module you don’t notice until it’s gone—and then you realize how much you relied on it.

Historical Context

The ADDAC 705 emerged during the early 2010s Eurorack renaissance, when the format was shifting from boutique curiosity to mainstream adoption. As more musicians took up modular synthesis, demand grew for reliable, high-quality utility modules. Noise generators became critical components, especially as users explored West Coast synthesis, sample-and-hold sequencing, and experimental sound design. Many early noise modules were either digital or repurposed from test equipment. The 705 filled that gap with a purpose-built analog design that put sonic quality ahead of gimmicks.

ADDAC System, based in Lisbon, had already built a reputation for musician-first design with its hybrid digital-analog instruments. The 705 was part of the company's move into Eurorack, where it focused on modules that addressed real-world patching needs without overcomplicating things. Some manufacturers were adding MIDI, CV processing, and digital displays to every module at the time. The 705 stood out for its restraint. Competitors like Intellijel and Make Noise offered noise sources, but often bundled them with other functions, like the Intellijel Rainmaker or Make Noise QPAS. The 705's single focus made it a favorite among purists and minimalists.

Collectibility & Value

The ADDAC 705 isn't a rare grail, but it isn't disposable either. Assembled units have been reported to sell for around £120-£160 on the used market, depending on condition and region. DIY kits, which were popular because of ADDAC's well-documented builds, can be found for as low as €90. Pre-built versions from trusted builders cost more. The circuit is entirely analog and uses standard components, so failure rates are low. There's no firmware to corrupt and no delicate ICs prone to overheating. The toggle switches can wear out with heavy use, especially in live setups, so check for crackling or intermittent output when buying used.

The 705 has no attenuation on board. If you feed it into a sensitive input, like a VCA or a filter with high resonance, you might need an attenuator or passive mult to tame the level. ADDAC assumed users would have those tools already. Extremely cold environments can cause slight drift in noise density, though this is rarely noticeable in practice. For collectors, the 705 isn't about investment value.

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