ADDAC507 - Synthesizer ADDAC System - Free user manual and instructions

Product Type	Eurorack synthesizer module
Brand	ADDAC System
Model	ADDAC507 Random Bézier Waves
Main Function	Dual random voltage generator with Bézier interpolation, evolving LFO-like modulation
Form Factor	10HP wide Eurorack module
Depth	4.5 cm
Power Consumption	+12V: 70 mA, -12V: 40 mA
Controls per Channel	Frequency, Level (attenuator/VCA), Offset (±5V), Curve (Bézier shape), Limit/Fold/Thru clip mode
CV Inputs	Frequency and Level each with attenuverter; internally normalized to the other channel's main output
Outputs	Wave, Inverted Wave, Gate (channel A: trigger at each random step; channel B: comparator), Average (A+B)/2, Inverted Average
Special Features	Bézier interpolation with adjustable control points; cross-patching via internal normalization; jumper-disablable normalization on rear PCB
Clip Modes	Limit (clamps at ±5V), Fold (wavefolds, doubles voltage range), Thru (inverts and appears at opposite polarity)
LED Indicators	Monitors per-channel voltage and gate outputs
Collaboration	Designed with Monotrail (Rijnder Kamerbeek)
Country of Origin	Portugal
Maintenance	Wipe with a dry cloth; avoid liquids and abrasive cleaners
Safety	Compliant with Eurorack standards; use only with Eurorack cases and power supplies
Reparability	Contact ADDAC System support for issues; internal jumpers allow disabling normalization; no user-serviceable parts beyond jumper manipulation
Manual	Free PDF available from ADDAC System website

Frequently Asked Questions - ADDAC507 ADDAC System

What is the ADDAC507?

The ADDAC507 Random Bézier Waves is a dual random voltage generator module for Eurorack. It produces smooth, evolving voltages by interpolating between random points using Bézier curves, functioning like a complex LFO.

How does the Bézier interpolation work?

The module generates two random voltage points per cycle. The curve control adjusts the position of Bézier control points: counterclockwise moves them vertically (exponential), noon is linear, and clockwise moves them horizontally (logarithmic). This determines the shape of the transition between random values.

What is the internal cross-patching normalization?

By default, each channel's main output is internally routed to the other channel's Frequency and Level CV inputs via the attenuverters. This enables automatic cross-modulation for chaotic or evolving behavior. Inserting a patch cable into any CV input disables the internal routing for that input. Jumpers on the back PCB can permanently disable these connections.

How does the curve control affect the wave?

The curve knob alters the interpolation shape between random points. At fully counterclockwise, the transition is exponential; at noon, linear; fully clockwise, logarithmic. This changes the voltage slope and character of the output wave.

What do the gate outputs do on each channel?

Channel A's gate outputs a 15ms trigger at the start of each new random cycle (clock output). Channel B's gate acts as a comparator: it outputs a high gate when the main output voltage is positive and low when negative or near zero.

What is the difference between Limit, Fold, and Thru?

Limit clamps the voltage at ±5V. Fold applies wavefolding when the voltage exceeds ±5V, effectively doubling the voltage range to allow more folds. Thru inverts the voltage and sends it to the opposite polarity (e.g., +5V becomes -5V).

Can I use the module with other Eurorack systems?

Yes, the ADDAC507 is a standard Eurorack module (10HP wide, 4.5cm deep) and can be used with any Eurorack case that provides +12V and -12V power. It draws 70mA on +12V and 40mA on -12V.

How do I power the module?

Connect the included power ribbon cable to your Eurorack power bus, ensuring correct orientation (red stripe typically indicates -12V). The module requires +12V (70mA) and -12V (40mA). Do not connect to other power sources.

Are there any firmware updates available?

The ADDAC507 uses a microcontroller but firmware updates are not user-accessible. Contact ADDAC System support for any updates or bug fixes. The module ships with stable firmware as of March 2024.

How do I reset or troubleshoot if it's not working?

Check power connections and ensure the module is properly seated. Verify that no patch cables are partially inserted. If the issue persists, remove all patch cables and try power cycling. For further help, contact ADDAC System at [e-mail].

USER MANUAL ADDAC507 ADDAC System

Instruments for Sonic Expression

Est.2009

INTRODUCING

ADDAC507

RANDOM

BÉZIER

WAVES

USER'S GUIDE. REVO1

March.2024

A collaboration with:

MONOTRAIL

ADDAC

System

From Portugal with Love!

WELCOME

This module started with an idea from Rijnder Kamerbeek aka Monotrail, a straightforward random generator with interpolation between random points making it something like a complex, ever evolving. LFO

The concept is simple. It contains two identical smooth random voltage generators. Each has a frequency, level, offset and curve control. The frequency control sets a steady pace with which bipolar random voltages are generated. The level control works like an attenuator/VCA on the output, reaching from max output to closed. The offset allows shifting the whole wave up and down on the voltage range. Curve determines the shape of the interpolation. The bipolar activity on the main outputs as well as gate outputs are visualised with LEDs.

Both Frequency and Level controls have a CV input with attenuator. When there is nothing patched into the CV inputs, these are internally connected to the main output of the other channel. This normalization makes it very easy to add randomization to the frequency or level for more depth, or of course, add cross-modulation for chaotic voltages.

The output VCAs are useful to dial in subtle and time-based modulation without the need for external VCAs. For example, to modulate the amount over time with an envelope, or use the other generator with slower speeds to add random changes to the level of a random voltage.

Both generators also have two other outputs. One is an exact inversion of the main output, so it responds to the level and CV input. This is great for stereo or inversed effect patches. The other is a simple pulse output, here there are two different behaviours, channel A outputs a pulse at every random generation, channel B acts like a comparator. Whenever the main is positive this comparator output is a high gate. And whenever the main output is negative or close to 0, there is no gate output. Great for random triggers or firing other events like envelopes.

A couple other outputs are also available and are obtained by averaging both channel main outputs. The first output is the average while the second is an inverted average.

CHANNEL A CHANNEL B

Tech Specs:

10HP

4.5cm deep

70mA +12V

40mA -12V

CONTROLS DESCRIPTION

[LEVEL] sets the voltage output range, with a maximum range of ±5V
[LIMIT/FOLD/THRU] sets what happens when the voltage hits the maximum range:
LIMIT: limits the value to the maximum ±5v
FOLD: folds the voltage like a standard wavefolder. In this setting the output voltage range is multiplied by 2 to allow more folds to happen.
THRU: voltage gets inverted and appears at the other polarity.

[OFFSET] moves the whole voltage output up or down with a maximum range of ±5V
[CURVE] sets the interpolation Bézier control points from exponential to linear to logarithmic.

OUTPUTS DESCRIPTION

[AB AVERAGE] & [INVERTED AVERAGE] the average and inverted average of channel A & B: (A+B)/2

[WAVE] The "wave" CV output

[INVERTED WAVE] The "wave" inverted CV output

LEDS MONITOR

The leds on top monitor each channel voltage and gate outputs

GATE OUTPUT

There are two [GATE] output behaviour depending on the channel.

CHANNEL A - CLOCK OUTPUT

The Gate output will be output a 15ms trigger at every new cycle.

CHANNEL B - COMPARATOR OUTPUT

The Gate output will be ON when the voltage output is above it's mid range position. As an example, if no offset is applied the gate will be ON while on the positive side and OFF when on the negative side

BÉZIER INTERPOLATION

As described in wikipedia "Bézier curves are widely used in computer graphics to model smooth curves. As the curve is completely contained in the convex hull of its control points, the points can be graphically displayed and used to manipulate the curve intuitively"

Here we take advantage of these control points to interpolate between the 2 random points, we approach the control points in a very controlled manner: they move vertically when the control knob turned counter clockwise (up to half the difference of the 2 random points) and move horizontally when turned clockwise (up to half of the cycle period). At noon the interpolation is linear.

The graphics on the right show examples of these principles with control points in red.

Shown below are three examples of the curve shapes over time, these are 3 particular cases with control knob positioned at: fully counter clockwise, noon and fully clockwise. Also shown the inverted wave output.

CURVE INTERPOLATION

Here you can see these three examples overlapped.

CROSS PATCHING

To allow for more dynamic and unpredictable behaviour, by default the module ships with Channel A output internally routed to Channel B Frequency and Level as well as Channel B output internally routed to Channel A Frequency and Level. The attenuverters control the gain of each input.

As we all know it is almost physically impossible to completely attenuate a cv input using attenuverters, there's always some minor leakage, if this effect in not desired. It is possible to internally disabling this routings via jumpers on the back.

Notice the jumpers location on the back pcb and the desired position for each of the 4 jumpers on the graphic below.

Whenever a jack is inserted this internal routing is physically disabled.

CHANNEL 2 OUTPUT TO:
CHANNEL 1 OUTPUT TO:

FREQUENCY A
LEVEL A

FREQUENCY B
LEVEL B
DEFAULT STATE

SIGNAL FLOW DIAGRAM

graph TD
    A["ON / OFF BACK JUMPER"] --> B["FREQUENCY A CV IN"]
    C["ON / OFF BACK JUMPER"] --> D["LEVEL A CV IN"]
    E["H I U A NORMALIZATION"] --> B
    E --> D
    B --> F["FREQUENCY A INITIAL"]
    B --> G["FREQUENCY A ATTENUERIER"]
    D --> H["LEVEL A INITIAL"]
    D --> I["LEVEL A ATTENUERIER"]
    D --> J["CLIPING A LIMIT / FOLI / THRU"]
    D --> K["OFFSET A"]
    D --> L["CURVE A"]
    M["A 7 B NORMALIZATION"] --> N["FREQUENCY U CV IN"]
    O["ON / OFF BACK JUMPER"] --> P["LEVEL B CV IN"]
    Q["ON / OFF BACK JUMPER"] --> R["FREQUENCY B INITIAL"]
    Q --> S["FREQUENCY B ATTENUERIER"]
    Q --> T["LEVEL B INITIAL"]
    Q --> U["LEVEL B ATTENUERIER"]
    Q --> V["OFFSET B"]
    Q --> W["CURVE B"]
    Q --> X["CLIPING B TIMI / FOLI / THRU"]
    Y["MCU"] --> Z["AVERAGE MIX"]
    Z --> AA["CATE A OUTPUT"]
    Z --> AB["INVERTED A WAVE OUTPUT"]
    Z --> AC["WAVE A OUTPUT"]
    Z --> AD["AVERAGE OUTPUT"]
    Z --> AE["INVERTED AVERAGE OUTPUT"]
    Z --> AF["WAVE A OUTPUT"]
    Z --> AG["INVERTED 4 WAVE OUTPUT"]
    Z --> AH["BATE 4 OUTPUT"]

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