ADDAC 506B VC Stochastic Function Generator Expansion ()
A 2 hp expander with four more trigger inputs and four more voltage outputs for the 506.
Overview
The 506B is not a standalone module. It's a compact black-panelled extension that attaches directly to the ADDAC506 VC Stochastic Function Generator and adds I/O without eating up rack space. It is 2 hp wide and 3U tall. It doesn't do any of the core processing itself, but it adds four trigger inputs and four CV random outputs, so you can drive and tap the 506's stochastic brain in more ways.
The 506B is not a plain copy of an old design. The original concept goes back to Teia's Stochastic Function Generator, a module introduced in 2013 that is now long out of production. ADDAC took the early concept, rebuilt it from the ground up, and reprogrammed the microcontroller to function as "a fully featured 4 voice 2 stage envelope and slew generator." That means the 506B's firmware does real work, shaping how triggers are interpreted and how voltages evolve over time. It isn't just passing signals along, even if what it's doing is controlled chaos.
The 506B is part of the ADDAC500 Series, a line of modules built around generative, probabilistic sound design. It is officially licensed, and Teia's name is formally acknowledged. It doesn't stand alone, but it turns the ADDAC506 from a self-contained randomness engine into something you can use with multiple voices. You can trigger voices independently or route random CVs to several destinations at once.
Specifications
| Manufacturer | ADDAC |
| Module Height | 3U |
| Module Width | 2 hp |
| Module Depth | 40 mm |
| Panel Colour | Black |
| Power supply | via the ADDAC 506 module |
| I/O | Four trigger inputs for the random engine. |
| I/O | Four CV random outputs from the random engine. |
Key Features
Expansion, not duplication
The 506B doesn't replicate the ADDAC506. It adds to it. The four new trigger inputs let you drive the 506's random engine from multiple rhythmic sources at the same time. You could clock different voices with separate sequencers, or use external percussion triggers to nudge the generator at unpredictable moments. On the output side, four additional CV random outputs mean you can modulate more parameters at once - pitch, filter cutoff, panning, envelope time - without daisy-chaining or attenuating shared outputs. It's a simple idea, and it helps most in larger systems where signal distribution is a constant balancing act.
Firmware with intent
The 506B is more than a dumb I/O expander. It draws power through the ADDAC506 and doesn't generate randomness on its own, but it runs a completely reprogrammed microcontroller. The firmware handles the timing, interpretation, and shaping of the four voice envelope and slew generation. Each of the four channels is a fully active stage with its own response characteristics, not a passive pass-through. All of that fits in a 2 hp footprint.
Licensed legacy
The 506B is officially licensed from Teia's Stochastic Function Generator, a cult-favourite module from 2013 that has been out of production for years. ADDAC partnered with the original concept instead of imitating or reverse-engineering it, and adapted it into their own ecosystem. That kind of licensing is still rare in Eurorack. The 506B doesn't replace the original Teia module.
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