ADDAC System ADDAC801 (2011)
A no-frills, 4HP mixer that does exactly what you need—and nothing more.
Overview
You know that moment when your rack’s getting crowded, you’re juggling three separate audio streams, and all you really want is a clean, compact way to blend them without eating up precious space? That’s the ADDAC801 Simple Mixer in a nutshell. It’s not flashy, it doesn’t morph, modulate, or memorize—just three input channels, each with its own attenuator knob, feeding into a single standard output and an inverted output. It handles both audio and control voltages, which means it’s just as useful for summing LFOs as it is for layering oscillators. The whole thing fits in a svelte 4 HP, making it one of those “how did I live without this?” modules that quietly becomes indispensable.
There’s a charm to its simplicity. No trim pots, no switches, no hidden modes—just knobs, inputs, and outputs. It’s the kind of module you patch into without thinking, the utility player that shows up every day and does its job. And while it doesn’t promise color or character, that might be the point: sometimes you don’t want flavor, you want clarity. The inverted output is a nice touch, letting you flip a signal’s polarity on the fly, which comes in handy for subtractive mixing or creating interesting CV inversions. It’s not a star, but it’s the stagehand that keeps the show running.
Specifications
| Manufacturer | ADDAC System |
| Model | ADDAC801 simple mixer |
| Format | Eurorack Module |
| Dimensions | 4 HP, 25 mm deep |
| Current Draw | 20 mA +12V, ? mA -12V, ? mA 5V |
| Channels | 3 channels mixer + inverted out |
| Function | 3 Channel Audio/CV Mixer |
| Controls | 1 Attenuator Knob per Channel |
| Outputs | 1 standard output, 1 inverted output |
Historical Context
The ADDAC801 was mentioned in a post on Matrixsynth on January 8, 2011, as being available for pre-order—marking its debut into the Eurorack ecosystem at a time when the format was gaining serious momentum among DIY and boutique builders. It belongs to the ADDAC800-series and is now categorized under the "ADDAC Legacy Modules" on the manufacturer’s website, suggesting it’s no longer in active production. While it didn’t reinvent the mixer category, it arrived when compact, affordable utility modules were in high demand, slotting in alongside other minimal 4HP designs from builders like Invy and STG.
Collectibility & Value
The ADDAC801 currently lists at $149 on Reverb, down from its original listed price of $185. Given its utility-first design and legacy status, it’s likely to appeal more to practical Eurorack users than to collectors hunting for rare or sonically distinctive gear. There’s no public data on common failures or repair needs, but the lack of complex circuitry suggests reliability isn’t a major concern. As with any discontinued module, availability will depend on secondhand turnover, and its modest footprint ensures it’ll remain relevant in space-conscious systems.
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