ADDAC 702 Dual Voltage Controlled Filter (2015–)

A dual-filter Eurorack beast that doesn’t just shape sound—it growls, grinds, and rewrites the patch with its own analog attitude.

Overview

The ADDAC 702 is a 16HP module built around two completely independent filters, a high-pass and a low-pass. It's temperamental and unpredictable. One minute it gives a smooth, vactrol-softened sweep with vintage warmth. The next it's snarling through diode clipping with real harmonic aggression. You don't dial in a sound so much as negotiate with it. It has a cult following among Eurorack users who are tired of pristine, predictable filtering.

The 702 isn't a clean room tool. It's inspired by the raw character of the Korg MS-20 filter, but ADDAC didn't just clone it. The high-pass and low-pass filters each have their own audio input and output. The interesting part is the voltage-controlled mix path that lets you blend them dynamically. One CV can sweep the mix from a subby growl to a needle-sharp whistle. You can also invert the phase of the mix output for hollow, phase-cancelled textures.

Each filter has its own post-filter distortion/fuzz circuit, and it's part of the architecture, not an afterthought. Flip the switch and a clean resonance spike turns into a sputtering, overdriven mess. It's analog saturation, not digital grit. Crank it and the 702 adds layers of harmonic complexity that feel more like overdriving a tube amp than running a signal through a module.

Specifications

Key Features

The Dual-Filter Duality: HP, LP, and Everything Between

Most dual-filter modules offer symmetry, two of the same thing with maybe a little cross-modulation. The 702 doesn't. It gives you a high-pass and a low-pass filter, each fully independent. You can run them in parallel for complex spectral shaping, or stack them in series for a resonant band-pass effect. There's also a coupling switch, inspired by the rare Oscar synthesizer, that ties the low-pass cutoff to the high-pass and uses the LP knob as an offset. That gives you moving band-pass zones that shift in width and center frequency with a single control, handy for evolving pads or rhythmic sweeps that feel organic rather than sequenced.

The voltage-controlled mix output is the real innovation. Instead of summing the two filters externally, the 702 blends them internally with a CV-controllable fader. You can automate the balance between the high and low ends in real time, say morphing from a subby drone to a glassy harmonic sheen with an LFO or envelope. It feels more like a miniature mixing console than a filter module.

Resonance with Bite: Clipping Paths and Character

Turn up the resonance on most filters and you get a smooth sine wave howl. On the 702 you get a choice of clean feedback, diode clipping or LED saturation, set by a three-position switch on the front panel. In "no clipping" mode it behaves like a classic analog filter, resonant but controlled. In "diodes" the peak distorts early, with a gritty, aggressive edge that suits industrial textures or overdriven leads. In "LEDs" the clipping is softer and more rounded. It's still saturated, but with a vintage warmth.

This isn’t just about distortion for distortion’s sake. It’s about giving the filter its own voice. In a system full of clean VCFs, the 702 stands out because it *ages* like analog gear—warm, slightly unpredictable, and full of character. The resonance clipping interacts with the post-filter fuzz circuit, creating cascading layers of saturation that can turn a simple sine wave into a roaring, harmonically rich monster.

Phase, Fuzz, and the Art of Controlled Chaos

The 702 doesn’t just filter—it transforms. Each of the three audio outputs (HP, LP, Mix) has a phase inversion switch, letting you flip the polarity on the fly. This isn’t just useful for live mixing; it opens up wild possibilities for phase cancellation when routing multiple outputs to a mixer. Send both HP and LP to separate channels, invert one, and suddenly your full-range sound develops a hollow, metallic center that feels like it’s being eaten from the inside. Combine that with the mix output and you’ve got a three-way spectral war happening in real time.

And then there’s the fuzz. Each filter has its own post-filter distortion stage, which can be engaged independently. This means you can fuzz the high end while keeping the low end clean, or vice versa. It’s not a subtle effect—it’s in-your-face, with a gnarly, almost speaker-rattling aggression when pushed. But it’s also musical. The distortion doesn’t obliterate the source; it enhances it, adding upper harmonics that make pads shimmer and drums punch through a mix. It’s the kind of circuit that makes you reach for sources you’d normally avoid filtering—noise, FM, even vocals—just to hear what the 702 will do to them.

Historical Context

The ADDAC 702 arrived in 2015, when Eurorack was shifting from boutique curiosity to mainstream modular dominance. Many new modules at the time were chasing digital precision, clean signal paths and easy usability. The 702 went the other way. It didn't pretend to be transparent and it didn't hide its quirks. ADDAC drew on the Korg MS-20, a synth known for its raw, unfiltered sound, and positioned the 702 as a tool for sonic rebellion.

It also arrived alongside a wave of "vintage-inspired" modules that used DSP to simulate analog warmth. The 702 doesn't simulate anything. It's built with discrete analog circuitry, so the distortion comes from real diodes and LEDs, and the filtering from real capacitors and transistors.

Competitors like the Doepfer MS-20 filter clones offered similar inspiration, but the 702 set itself apart with its dual-filter topology and integrated mix path. It could reshape entire patches in ways that took multiple modules elsewhere. It shared DNA with the Make Noise QPAS or the Intellijel Metropolis, but with a rawness those modules often polished away.

Collectibility & Value

The ADDAC 702 has never been a budget module, and it hasn't gotten cheaper. New units still list around €385 - $405 direct from ADDAC, and custom-colored panels add a premium with a 4-6 week lead time. On the used market, prices vary widely based on condition and panel color. Standard black panels typically sell for €250 - €320 in good condition, while rare custom colors (like bronze or silver gray) can fetch €350 or more from collectors.

The 702 is not a plug-and-play relic. It's an analog circuit, and it can develop issues. The most common failure points are the toggle switches, especially the resonance clipping and phase inversion switches, which can become scratchy or intermittent with heavy use. The potentiometers are high-quality, but they can degrade over time, particularly if the module is adjusted often in a live setting. The distortion circuits draw significant current and can stress power supplies if the bus board isn't properly regulated.

Owners report that the module is generally reliable, but it needs maintenance. Cleaning the switches and pots every few years keeps it running smoothly. The LEDs are useful for monitoring output levels, but they aren't critical to function and can be replaced if they fail. There are no known design flaws that make the 702 prone to catastrophic failure, no capacitors known to leak and no ICs that routinely die. It's not indestructible, though. Keep it in a well-ventilated case, avoid overloading the inputs, and it should last for decades.

For buyers, the key is to test every switch and pot before purchasing. Ask for a demo video showing the mix CV in action, the resonance sweep with and without clipping, and the phase inversion on all three outputs. If the seller can’t provide that, walk away. The 702 is too nuanced to buy blind. And while it’s tempting to go for a rare panel color, remember: the sound doesn’t change. The black panel sounds just as ferocious as the bronze.

eBay Listings

ADDAC ADDAC702 Dual VC Filter Modular EURORACK - NEW - PERFE

$484

As an eBay Partner, we earn from qualifying purchases. This helps support our independent vintage technology research.

Related Models

• ADDAC System 200PI Pedal Integrator
• ADDAC System 213A Eurorack Bridge
• ADDAC System 403
• ADDAC System 705 Dual Noise
• ADDAC System 813
• 2hp DC
• 2hp Fold
• 2hp LPG V2
• 2hp Rash
• 2hp VCM