ADDAC System 705 Stinggy Filter (2010s)

A jagged little pill of a filter that bites back when you push it—like the Wasp filter’s feral cousin who never learned to play nice.

Overview

Plug in a clean sine wave, turn up the resonance, and within seconds you’ll feel like the module is arguing with you. The ADDAC 705 Stinggy Filter doesn’t just filter sound—it rewires your expectations of what a compact Eurorack filter can do. Born in the early 2010s, when Eurorack was shedding its niche skin and charging into the mainstream, the 705 arrived not as a polite utility but as a character-driven anomaly: a multimode filter with the DNA of the EMS Wasp synth’s famously raw filter, stretched, distorted, and stuffed into 8HP of 3U real estate. It doesn’t smooth edges—it gnaws on them.

What makes the 705 so electric is how it weaponizes imperfection. Unlike the surgical precision of a state-variable filter (SVF) from Make Noise or Intellijel, the Stinggy Filter leans into its quirks. The resonance doesn’t just peak—it warbles, howls, and sometimes seems to modulate itself when pushed into self-oscillation. This isn’t a flaw; it’s the point. Owners report that at high Q settings, the filter develops a kind of “juicy warble,” a harmonic instability that feels alive, almost unpredictable. It’s the sound of analog chaos held on a leash, and when you add the onboard distortion circuit, that leash starts to fray.

Despite its compact size, the 705 offers four independent filter outputs—low-pass, band-pass, notch, and high-pass—each with its own dedicated jack. That alone makes it a routing powerhouse, letting you split and process different frequency bands in parallel. But the real magic lives in the main output, where a four-position switch selects the final filter type, and a dedicated distortion/fuzz circuit adds layers of harmonic grit. This isn’t just overdrive slapped on at the end—it’s baked into the signal path with intention. The distortion can be subtle, adding warmth and presence, or cranked into full-on fuzz, turning even a simple sequence into something that sounds like it’s being eaten by a robot.

And then there’s the clipping circuit—a pair of switches that let you choose between no clipping and diode clipping for the resonance path, and another for resonance depth (high or low). These aren’t just tone tweaks; they fundamentally alter how the filter behaves under pressure. With diode clipping engaged, the resonance gains a snarling edge, perfect for industrial textures or aggressive leads. Without it, the filter cleans up slightly, though “clean” here is relative—this is still a module that prefers drama over diplomacy.

It’s not a filter for every patch. If you’re looking for transparent filtering, silky sweeps, or precise frequency sculpting, look elsewhere. But if you want a filter that *performs*—that reacts, bites, and surprises—then the 705 earns its place. It’s the kind of module that makes you rethink patches you thought were finished, simply by inserting it and twisting a few knobs. It’s also telling that so many owners describe it as “versatile,” not despite its character, but because of it. The 705 doesn’t disappear into your rig—it becomes a voice.

Specifications

Key Features

The Wasp Filter Reimagined

The EMS Wasp synth’s filter, designed in the late 1970s, was never known for its neutrality. It was raw, aggressive, and prone to self-oscillation—qualities that made it beloved by experimental musicians and despised by purists. ADDAC didn’t just clone it; they amplified its personality. The 705 retains the Wasp’s core topology but adds voltage control over cutoff (with attenuverter), making it far more flexible in a modern Eurorack context. Unlike the original Wasp filter, which required external circuitry to reach self-oscillation, the 705 gets there on its own, turning into a shrieking oscillator when resonance is maxed. This isn’t just a filter—it’s a sound source in its own right, capable of generating tones that feel unstable, organic, and deeply musical in their imperfection.

Distortion as a Design Philosophy

Most filters treat distortion as an afterthought—an overdrive circuit tacked onto the output. The 705 treats it as a core feature. The distortion/fuzz on the main output isn’t a separate effect; it’s part of the filter’s voice. When engaged, it interacts dynamically with the resonance and input gain, creating harmonics that feed back into the filtering process. This creates a kind of feedback loop where the distortion colors the input, which then gets filtered, which then distorts again. The result is a sound that evolves as you tweak it, never quite settling. Service technicians observe that the distortion circuit uses silicon diodes and op-amp overdrive stages, allowing for multiple flavors of saturation—from soft clipping to full-on fuzz—depending on input level and distortion knob position.

Four Outputs, One Identity

Having independent outputs for each filter type isn’t just convenient—it opens up complex patching possibilities. You can send the low-pass to a reverb, the band-pass to a delay, and the high-pass to a compressor, all from a single source. This kind of parallel processing was rare in 8HP modules at the time, and it speaks to ADDAC’s focus on utility without sacrificing character. The main output, selected via a 4-position switch, acts as the “final mix” of the filter, complete with distortion and phase inversion. That phase switch, while subtle, can be crucial when layering multiple filters or syncing with external gear—sometimes flipping polarity is all it takes to make a patch click.

Historical Context

The 705 arrived during Eurorack’s explosive growth phase, when the format was shifting from DIY curiosity to professional studio tool. In that climate, many manufacturers leaned toward refinement—clean designs, precise tracking, transparent sound. ADDAC went the opposite direction. The 705 wasn’t trying to be the most accurate filter; it was trying to be the most *interesting*. It shared shelf space with modules like the Mutable Instruments Ripples and the Make Noise QPAS, both of which offered smoother, more controllable filtering. The 705 stood out by embracing its roots in the lo-fi, punk ethos of the EMS Wasp—a synth that was itself a product of economic constraint and creative necessity.

At the time, there was a quiet rebellion against the idea that analog meant “warm” or “smooth.” Modules like the 705, the Intellijel Diode Filter, and the Tiptop Audio Z4000 Filter Frenzy celebrated the gnarly, the unstable, the unpredictable. The 705 fit perfectly into that movement, offering a kind of controlled chaos that felt fresh in a market increasingly dominated by digital precision. It also reflected ADDAC’s broader philosophy: hybrid instruments that blurred the line between analog and digital, between utility and expression. The 705 wasn’t just a filter—it was a statement.

Collectibility & Value

The ADDAC 705 Stinggy Filter has settled into a quiet but devoted following. It’s not a “hype” module, but it’s not obscure either. On the used market, assembled units typically sell between $180 and $250, depending on condition. Units described as “excellent” with original packaging and accessories can fetch the higher end, while those with cosmetic wear (“mild rack rash”) or untested status dip closer to $160. The DIY kit, originally priced at €119, occasionally appears on eBay or Reverb for $100–$140, though many buyers prefer the assembled version due to the module’s SMD components.

One of the 705’s strengths is its reliability. Documentation shows a straightforward analog design with no known systemic failures. Unlike some vintage filters that suffer from capacitor drift or op-amp degradation, the 705’s circuit is robust, and service technicians report few issues beyond standard cleaning and recalibration. The knobs are noted for their resistance—similar to Doepfer’s—making fine adjustments easier but fast sweeps slightly stiff. This is generally seen as a positive, given how sensitive the resonance and distortion controls are.

Buyers should check for a few things before purchasing: first, verify that all four filter outputs are functioning, as cold solder joints on the output jacks have been reported in early production runs. Second, test the distortion circuit with a clean input signal to ensure it responds smoothly across its range. Third, confirm that the resonance reaches self-oscillation—some units may have a slightly lower threshold due to component tolerances. And finally, if buying a kit, ensure all SMD components are present and undamaged, as replacements can be hard to source.

The 705 isn’t a module that will skyrocket in value—it’s too recent, too niche. But it’s also not going to fade into obscurity. For players who value character over conformity, it’s a keeper. It’s the kind of module that, once installed, rarely gets removed. And in a format where modules rotate in and out like seasons, that’s high praise.

eBay Listings

ADDAC System ADDAC 705 Stinggy Filter - Excellent Condition

$169

ADDAC ADDAC705 Stinggy Filter Modular EURORACK - DEMO - PERF

$244

ADDAC ADDAC705 Stinggy Filter Modular EURORACK - USED - PERF

$269

ADDAC ADDAC705 Stinggy Filter Modular EURORACK - NEW - PERFE

$319

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