ADDAC System ADDAC702 (2020s?)

Two filters in one, built like a tank, and wired with enough flexibility that 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.

It's inspired by the Korg MS-20 filter. That shows up in the grit, the growl, and the way resonance goes from smooth to snarling with a twist. But the 702 isn't a clone. It's expanded and refined, with extra features. It's part of the ADDAC700 Series, so it's designed to play well with the other modules there, but it's self-contained enough to sit at the center of a patch.

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 has its own attenuator. So you set how much modulation actually hits the parameter. Sledgehammer or scalpel, and the 702 gives you the scalpel.

Smooth Operator

The Smooth circuit imitates a bit of analog imperfection. Flip the switch and the cutoff control behaves more like a vactrol-based system - slower and softer, with a gentle lag that smooths out fast CV changes. It's more than a lag processor. Engage Smooth for a syrupy filter sweep like on a vintage string machine. Leave it off for sharp cutoff changes and rhythmic gating.

Coupling from the Oscar

The Coupling switch ties the high-pass and low-pass cutoff frequencies together, so you can 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 changes the workflow quite a bit. Instead of managing two separate cutoffs, you get one tonal control, like a band-reject or band-pass effect that moves as one.

Resonance with a Bite

The three-position resonance clipping switch sets how the filter behaves at high resonance: diodes, no clipping, or LEDs. Diodes give you a classic, slightly compressed saturation. LEDs give a different clipping profile, brighter and maybe a bit more aggressive. "No clipping" lets you hear the raw behavior of the circuit, even if it risks instability at extreme settings. It's rare to see this much resonance shaping on a modern filter.

Distortion Built In

Each filter has a post-Distortion/Fuzz circuit. It sits in the signal path and adds harmonic complexity after filtering. You can clean up a fuzzy source, or make a clean source filthy, all within the same module. It works well with the phase switches on the outputs, which flip the polarity of the HP, Mix, or LP signals. That matters 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 give you a real-time view of how the signal is moving through the filter stages. In a dark rack they pulse in a pretty way.

Historical Context

The ADDAC702 is ADDAC System's debut in voltage-controlled variable filters. It's part of the ADDAC700 Series, a lineup of precision Eurorack modules, and it's the flagship-level filter design there. No exact release date has been confirmed, but 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, and fits those ideas into a 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. The average user rating on ModularGrid is Ø 5.00 from two votes, though the sample size is small. No common failures or maintenance issues have been reported. Given its build quality and the trimmers on the front panel (for adjusting resonance behavior, per user reports), it's likely serviceable with basic tools.