We Are ADDAC System.

We Craft Instruments
For Sonic Expression.

About Us

ADDAC System is an Eurorack Modular Manufacturer based in Lisbon, Portugal, established in 2009. We know you already know us from our extensive catalog. We've been here since the very start of the new Eurorack revolution.


ADDAC506 VC Stochastic Function Generator

We've been quietly developing these modules for the past 6 months. They're inspired and officially licensed from Teia's Stochastic Function Generator which was introduced in 2013 but is no longer available.
We used the concept of the early version but completely rebuilt and reprogrammed it's mcu to a fully featured 4 voice 2 stage envelope and slew generator.


This new module + expansion is our take on a different envelope/slew generator. It's a fully featured Quad Analogue Core Envelope Generator and Slew Processor with digital control which also incorporates built in random generators to control the Rise and Fall times.
Covering the full range from short sharp notes to long slow sweeps of up to 6 minutes. Together with the random generators it excels when used for drone soundscapes.
Used as a Slew Processor the random generators act as dynamic modulation sources affecting the rise and fall slew speed.
Fully featured outputs act as encouragement to self-patching creating interdependent envelopes acting in sync.


Four independent Rise / Fall generators with individual timing controls.
Built in random generators for Rise and Fall Time each with Minimum and Maximum controls. Three gate/trigger outputs per channel: End of Rise, End of Fall plus the standard Rise Gate output.
Two extra CV outputs with the Sum and the Average of all 4 voices cv outputs.
Four trigger inputs for the random engine.*
Four CV random outputs from the random engine.*
Dedicated attenuverters for amplitude and offset of each voice CV output. No more need for external attenuators, offsets and inverters.

* Available through the Expansion Module.


We finished all development a month ago! Meanwhile already received all parts for the first batch and almost finished the PCBs assembly.
Due to summer holidays panels got delayed but they just arrived and from now on we'll be focused into finishing the first batch which shouldn't take more than a few weeks to have them tested and out the door!
All the assembly is being done in our own Pick n'Place machine which means no more delays are expected!


We ship from Lisbon, Portugal.
Typically we charge 15€ to ship within the EU, 40 € for North America and 45€ for the Rest of the World.
We plan to start shipping the Early Birds' batches of 20 by the end of September.
Main batch will follow by the end of October.

Download the PDF with Features Description + Signal Flow Diagram


ADDAC506 Picture Gallery.

Browse through the gallery of the module.
Final version will feature a black panel with white print.

ADDAC506 Pack

ADDAC506 + ADDAC506B Final prototypes.

Front View

Vector panel layout.

Signal Flow Diagram

A working diagram + Features Description PDF: Download User's Guide

Printed Circuit Boards

PCBs batch ready to start assembly!

Assembly Line

Our modest Pick n'Place machine will take good care of all those pcbs.

Assembly View

The PCBs being assembled in our pick n'place machine.

Side View

A few of the frankenstein prototypes that didn't made the cut.

TEIA's Original Module

You can check all about it in the Original Muff thread

ADDAC506 VC Stochastic Function Generator

Tech Specs

Tech Specs

width: 20HP
200mA +12V
150mA -12v

width: 2HP
10mA +12V
10mA -12v

CV Output Range

Each channel CV output range can be set with the [Amplitude] and [Offset] attenuverters.
Amplitude can be set to a maximum of 10v peak to peak(pp), ex 0 to +10v or -5v to +5v.
Offset can as a maximum range of 20v peak to peak and allows to offset the CV to ±10v.

Trigger + Loop Mode

Using it in [Trigger + Loop] mode creates a triangle LFO type output.
In fast speed setting this mode can go into audio range and up to 1Khz.

One Shot Mode

Using it in One Shot Mode makes it a standard trigger/gate dependent envelope.
Whenever a trigger is received it will trigger the envelope to go through its 2 stages. Whenever a gate is received it will trigger the Rise stage of the envelope and stop at the maximum range until the gate is removed, after the gate goes down the envelope will enter the Fall stage.

Slew Mode

Using it in Slew Mode makes it behave like an envelope follower for CV. Any CV input going in will be lagged according to the [Rise] and [Fall] settings. Every time the CV input goes up it's lagged by the [Rise] settings, if the CV input goes down then the [Fall] controls will determine its lag.
This mode is very effective to generate Portamento/Glide effects from an incoming quantized source.

Self Patching

You can self patch the module so that the envelopes trigger each other generating a cascading behaviour.
Users can set all voices to [One Shot + Trigger] and then patch voice 1 End of Rise or End of Fall to voice 2 trigger input. Then patch voice 2 to voice 3 trigger input and so on. Finally patch voice 4 to voice 1 and all 4 envelopes will be triggering each other in sync allowing for more complex interdependent controls.


Order one now.

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If you're in the EU buying with a VAT Exempt number please provide the number anywhere in the form.

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addac [at] addacsystem [dot] com