ADDAC System ADDAC702 (2020s?)
Two filters in one, built like a tank, and wired with the kind of surgical flexibility that makes you forget you’re patching a synth—until it snarls.
Overview
The ADDAC702 Dual Voltage Controlled Filter isn’t just another dual-filter module—it’s a surgical suite for sound. Built by ADDAC System as their first foray into voltage-controlled variable filtering, it packs two fully independent filters into a single 16 HP Eurorack slot: one high-pass, one low-pass, each with its own input and output. That alone would make it useful. But the 702 doesn’t stop at utility. It’s built with a musician’s ear and a technician’s precision, offering a level of control that borders on obsessive. You can run them in parallel for split processing, stack them in series (HP into LP) for steeper slopes, or blend them with a voltage-controlled mix that lets you morph between extremes in real time. It’s the kind of module that doesn’t just filter sound—it reshapes your approach to patching.
And yes, it’s inspired by the Korg MS-20 filter. That lineage shows up in the grit, the growl, the way resonance can go from smooth to snarling with a twist. But the 702 isn’t a clone. It’s a reimagining—expanded, refined, and loaded with features that feel both nostalgic and forward-thinking. The fact that it’s part of the ADDAC700 Series tells you it’s designed to play well with others in the ecosystem, but it’s also self-contained enough to be a centerpiece.
Specifications
| Manufacturer | ADDAC System |
| Model | ADDAC702 Dual Voltage Controlled Filter |
| Product Type | Eurorack module, Dual Voltage-Controlled Variable Filter |
| Dimensions | 16 HP |
| Depth | 40 mm |
| Current Draw | 80 mA +12V, 80 mA -12V, ? mA 5V |
| Price | $405 |
Key Features
Two Filters, One Mind
Each filter—high-pass and low-pass—has its own audio input and output, so you can process two signals independently or route one through both. The Cutoff and Resonance controls are voltage-controllable, and each CV input comes with its own attenuator. That means you don’t just modulate—you fine-tune how much modulation hits the parameter. It’s the difference between a sledgehammer and a scalpel, and the 702 gives you the scalpel.
Smooth Operator
The Smooth circuit is a clever nod to analog imperfection. Flip the switch, and the cutoff control behaves more like a vactrol-based system—slower, softer, with a gentle lag that smooths out fast CV changes. It’s not just a lag processor; it’s a character switch. Want that smooth, syrupy filter sweep like on a vintage string machine? Engage Smooth. Need razor-sharp cutoff changes for rhythmic gating? Leave it off.
Coupling from the Oscar
The Coupling switch ties the high-pass and low-pass cutoff frequencies together, letting you sweep both with a single control. This feature is directly inspired by the Electronic Dream Plant (EDP) Oscar synthesizer—a cult classic known for its dual-filter architecture. It’s a small detail, but it changes the workflow completely. Instead of managing two separate cutoffs, you get a unified tonal control, like a dynamic band-reject or band-pass effect that moves as one.
Resonance with a Bite
The three-position resonance clipping switch lets you choose how the filter behaves at high resonance: diodes, no clipping, or LEDs. Diodes give you that classic, slightly compressed saturation. LEDs offer a different clipping profile—brighter, maybe a bit more aggressive. And “no clipping”? That’s for the purists who want to hear the raw, unfiltered (so to speak) behavior of the circuit, even if it risks instability at extreme settings. It’s rare to see this level of resonance shaping on a modern filter, and it speaks to ADDAC’s commitment to tonal variety.
Distortion Built In
Each filter has a post-Distortion/Fuzz circuit. This isn’t an afterthought—it’s baked into the signal path, letting you add harmonic complexity after filtering. You can clean up a fuzzy source, or make a clean source filthy, all within the same module. It’s especially effective when used with the phase switches on the outputs, which let you flip the polarity of the HP, Mix, or LP signals. That’s crucial when layering or summing outputs, especially in feedback patches where phase alignment can make or break the sound.
Visual Feedback
Three LEDs monitor the amplitude of the high-pass, mix, and low-pass outputs. They’re not just decorative—they’re functional, giving you a real-time view of how the signal is moving through the filter stages. In a dark rack, they’re also kind of beautiful, pulsing like twin hearts with a shared rhythm.
Historical Context
The ADDAC702 marks ADDAC System’s debut in the world of voltage-controlled variable filters. As part of the ADDAC700 Series, it fits into a broader lineup of precision Eurorack modules, but stands out as a flagship-level filter design. While no exact release date has been confirmed, its presence in current dealer backorders and recent used listings suggests it emerged in the early 2020s. It draws clear inspiration from the Korg MS-20 and the EDP Oscar, but rather than replicate, it integrates those ideas into a modern, modular-first workflow.
Collectibility & Value
The ADDAC702 is not easy to find new—Juno Records lists it as “Click ‘email me when available’,” suggesting limited production or high demand. Used prices vary: CHF240 in Switzerland (listed March 10, 2026) and €280 in the EU (January 13, 2026) indicate a market holding steady below the original $405 price point. Yet a merchant listing on Reverb shows a price of $507.41, possibly reflecting scarcity or regional markup. With an average user rating of Ø 5.00 from two votes on ModularGrid, it’s clearly resonating with those who own it—though the sample size is small. No common failures or maintenance issues have been reported, but given its build quality and the presence of trimmers on the front panel (for adjusting resonance behavior, per user reports), it’s likely serviceable with basic tools.
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