ARC Nano Modules ARC Function Generator User Guide

Double check the power cord polarity to avoid damaging
electronic circuits.
Ensure the RED mark at the PCB power connector matches the
colored line on the ribbon cable.

Check all connections and then turn on your modular
system.
If any anomalies are noticed, turn off the system immediately
and recheck connections.

Description

ARC is an analog Dual Function Generator with two independent
channels and a versatile common section. Each channel can be used
for precise control over RISE and FALL times, adjustable SHAPES,
and additional features like SUSTAIN mode and OFFSET adjustment.
ARC is designed to shape and modulate audio and control signals for
smooth transitions, complex envelopes, and precise modulation.

Layout

The module features RISE & FALL controls for shaping the
signal dynamics. The Manual Gate allows real-time envelope
triggering, while Offset fine-tunes the signal’s DC offset. Outputs
include RISE | FALL gate signals and primary outputs for each
channel.

Common Section

The Common Section includes switches for controlling the overall
timing range (SPEED), looping function (LOOP), and sustain
behavior. The Logic Section offers functions like X>Y
comparison, signal summation (SUM), and logic operations (OR).

FAQ

Q: How do I adjust the Rise and Fall times?

A: You can control the Rise and Fall times using the RISE and
FALL knobs respectively. Additionally, external CV inputs can be
used to modulate these times.

Q: What is the purpose of the Logic Section?

A: The Logic Section provides functions for comparing channel
outputs, combining signals, and performing logical operations,
enhancing the versatility of modulation possibilities.

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ARC
Quick guide
NANO Modules – València 2024 ©

Thank you for choosing ARC for your Eurorack System.
Powering up
1. Turn off the power of your modular synthesizer. 2. Double check the power cord polarity. If you plug the module backwards you might
damage its electronic circuits.

RED

If you flip over your ARC, you will find the “RED” mark at the PCB power connector, which must match the colored line on the ribbon cable.

3. Once you have checked all the connections, you can turn on your modular system.
4. If you notice any anomalies, turn your system off right away and check again your connections.

ARC

NANO Modules – València 2024 ©

Description
ARC is an analog Dual Function Generator which features two independent channels and a versatile common section, equipped with advanced functionalities.
Each channel can be used as:
· Envelope generator (AD/ASR) · Audio & Low-frequency oscillator (VCO/LFO) · Slew limiter · Waveform Modulator (VCA/Polarizer)
With dedicated trigger and signal inputs, ARC allows for fine-tuned control over RISE and FALL times, adjustable SHAPES (linear, logarithmic, or exponential), and a range of additional features including SUSTAIN mode, OFFSET adjustment, and a built-in Logic Section.
Designed to be the heart of your modular setup, ARC allows you to shape and modulate both audio and control signals, offering everything from smooth transitions and complex envelopes to precise modulation, making it the go-to module for those who demand more from their modulation sources.

ARC

NANO Modules – València 2024 ©

Layout · General view
This image will clarify the function of each of the elements of the module.

CHANNEL X X
RISE

COMMON SECTION ARC
RISE OUT FALL

CHANNEL Y Y
RISE

SPEED

LOOP

OFF

ANUAL GAT

FALL

ANUAL GAT

SUSTAIN

OFF

POL

VCA

-5 +5
OFFSET

–

X OUT

X LOOP Y X ATT·VER Y

–

Y OUT

-5 +5
OFFSET

TRIG

RISE

EXP

FALL

X>Y

SUM

RISE

EXP

FALL TRIG

RISE X OUT

FALL

AND

RISE Y OUT

FALL IN

M POL

E VCA

ARC

Layout
This image will clarify the function of each of the elements of the module.

RISE & FALL Shape
Control the shape of the Rise or Fall time, between Exponential Linear Logarithmic
Manual Gate
Trigger the envelope manually for
real-time control.
Offset
Fine-tune the DC offset of the signal, adjustable between -5V and +5V.
Outputs
RISE | FALL Gate output that is high when
the rise or fall phase is active.
X OUT Primary output for channel X, providing the function generator
signal.

M POL

VCA E

CHANNEL X X

RISE

ANUAL GAT

FALL

-5 +5
OFFSET

–

X OUT

TRIG

RISE

EXP

FALL

RISE X OUT

FALL

RISE & FALL
RISE knob controls how quickly the signal reaches its peak. FALL knob controls how quickly the signal returns to its baseline.
Attenuverter
· Polarizer. Phase inversion. · VCA. Amplitude modulation.
CV IN
RISE | FALL Controls the Rise/Fall time of the envelope or modulation signal via an external CV. EXP Modulates the exponential response of the Rise and Aall times, affecting the main frequency of the function.

ARC

NANO Modules – València 2024 ©

Layout
Common Section This section includes shared controls from both channels seamlessly.

Switches
SPEED Controls the overall timing range of the rise and fall times.
LOOP Toggles the looping function
of the envelope.
SUSTAIN Controls whether the envelope
holds at its peak or not
Logic Section
X>Y Outputs a high signal when
the X channel is greater than the Y channel.
SUM Combines Channel X & Y
signals into one.
OR Outputs the higher voltage
of X or Y channels.
AND Outputs the lower voltage
of X or Y channels.

SUSTAIN

LOOP

SPEED

ARC
RISE OUT FALL

ON OFF ON OFF

X LOOP Y X ATT·VER Y

X>Y

SUM

AND

SUSTAIN

LOOP

SPEED

LED Indicators CV IN

ARC

NANO Modules – València 2024 ©

Layout
Channel Y Same as Channel X .

CHANNEL Y Y

POL M

RISE

FALL

ANUAL GAT

E VCA

–

Y OUT

-5 +5
OFFSET

RISE

EXP

FALL TRIG

RISE Y OUT

FALL

Trigger
Trigger input for the envelope.
Signal Input
Signal input that feeds into the slew limiter

ARC

NANO Modules – València 2024 ©

Envelope Generator AR/ASR
Use the RISE & FALL controls to create simple AD envelopes for punchy and percussive sounds.
For ASR envelopes, turn on the Sustain switch! The envelope will rise to the peak and hold there while the Gate is active.
Audio & Low Frequency Oscillator
ARC features RISE & FALL frequency adjusts and a SPEED switch with three positions (slow, mid, fast) to cover all possible needs.
Turn on the LOOP switch to convert the function generator into an oscillator. Use the previous controls to match the required frequency.
ARC can generate a huge range of frequencies for producing both audio-rate signals for pitched sounds and ultra slow waveforms for modulation purposes.
Slew Limiter & Waveform Modulation
· Slew limiter Smooth out abrupt changes in CV & audio signals to create filtering and portamento effects .
· Waveform Modulation Adjust Rise and Fall shapes to create logarithmic, linear, or exponential shapes over your input signal.
ARC

SPEED

SPEED SPEED
LOOP

AR ASR GATE
Fig.1 Speed Switch Configuration & Graph for AR/ASR Envelopes
ON OFF
Fig.2 LOOP Switch ON & Graph for Speed Ranges
Signal Input Function Out
Y
RISE
FALL
Fig.3 Waveform Modulation Knobs & Graphic representation example
NANO Modules – València 2024 ©

VCA & Signal Inversion (POL)
The VCA/POL adjusts the volume of the signal, acting as a traditional VCA for dynamic level control.
Additionally, the POL function modifies the polarity, enabling both positive and negative modulation for more complex sound shaping.
The OFFSET function can add or subtract a voltage from -5V to 5V to match the required signal range.
Logic Section
ARC includes a X > Y gate logic output, which compares the two function signals and outputs a gate when X is greater than Y.
Additionally, the module provides the SUM of X and Y functions, as well as OR and AND logic functions.

0V
Signal Input Function Out

POL

VCA

-5 +5
OFFSET

–

X OUT

Fig.4 Detail of X·OUT Attenuverter & Offset Knobs & Graphic Representation example

ARC

X>Y

SUM

AND

Fig.5 Detail of Logic Outputs and its graphic representaion

Controls / Channel X & Y
· RISE & FALL
RISE: Controls how quickly the signal reaches its peak. Turn clockwise for a slower, smoother rise; counterclockwise for a faster, sharper rise.
FALL: Controls how quickly the signal returns to baseline. Clockwise for a gradual fall; counterclockwise for a quicker drop.
· RISE & FALL Shape Adjusts the curve of the rise and fall times between Exponential, Linear, and Logarithmic.

RISE
FALL
Fig.6 Detail of RISE & FALL Knobs
logarithmic linear exponential Fig.7 Detail of RISE Shape Knob & its graphic representation exponential linear
logarithmic Fig.8 Detail of FALL Shape Knob &
its graphic representation

ARC

Controls / Channel X & Y
· Manual Gate Manually trigger the envelope for real-time activation.
· Offset DC Offset Adjustment: Adjusts the signal’s baseline voltage between -5V and +5V, aligning it with your needs or ensuring the correct modulation starting point.
· Attenuverter Acts as a polarizer and amplitude controller. It allows you to control the amplitude and invert the phase of the signal.

POL M

VCA E

ANUAL GAT Fig.9 Detail of Manual Gate Button
-5 +5
OFFSET Fig.10 Detail of Offset Attenuverter

–

X OUT

Fig.11 Detail of POL/VCA Attenuverter

ARC

Controls / Channel X & Y
· Inputs
/IN This is the signal input that feeds into the slew limiter. It smooths out and shapes incoming signals.
/TRIG The trigger input for the envelope. When a trigger signal is received, it activates the envelope, initiating the rise and fall phases according to the set controls.
· CV Inputs
/RISE | FALL Controls the Rise/Fall time of the envelope or modulation signal via an external CV.
/EXP Modulates the exponential response of the Rise and Aall times, affecting the main frequency of the function.
· Outputs
RISE | FALL Gate output that is high when the rise or fall phase is active.
X OUT Primary output for channel X, providing the function generator signal.

TRIG
IN Fig.12 Detail of TRIG & IN Inputs

RISE

EXP

FALL

Fig.13 Detail of CV IN Inputs

RISE X OUT FALL Fig.14 Detail of Outputs

ARC

Contols / Common Section
· LED Indicators
RISE This LED lights up during the rise phase of the envelope or function generator, indicating that the signal is increasing toward its peak.
OUT (Bicolor) This bicolor LED shows the output status of the module.
It typically changes color based on the signal polarity or state, allowing you to quickly assess whether the output is positive, negative, or at zero.
FALL This LED lights up during the fall phase, showing that the signal is returning to its baseline or completing its cycle.
· Switches
SPEED This switch controls the overall timing range of the rise and fall times.
· MID. A balanced range for medium-speed transitions. · HIGH. For fast, snappy envelopes, ideal for percussive sounds or quick modulation changes · LOW. For very slow envelopes and modulations.

SPEED

RISE OUT FALL Fig.15 Detail of LED Indicators
Fig.16 Detail of Speed Switch

SPEED

ARC

Contols / Common Section
· Switches
LOOP Toggles the looping function of the envelope. · ON. The envelope will continuously loop, creating a repeating cycle without the need for external triggering. · OFF. The envelope will function normally, only triggering once per trigger signal.
SUSTAIN Controls whether the envelope holds at its peak. · ON. The envelope will sustain at the peak level as long as the gate or trigger signal is active, only proceeding to the fall phase once the gate is released. · OFF. The envelope will immediately proceed to the fall phase after reaching the peak, without holding.

SUSTAIN

LOOP

ON OFF Fig.17 Detail of Loop Switch
ON OFF Fig.18 Detail of Sustain Switch

SUSTAIN

LOOP

ARC

Contols / Common Section
· CV Inputs
LOOP Applying a voltage of more than 2V to this input activates the loop mode, causing the function generator to repeat its cycle continuously, without needing manual activation or a gate signal.
ATT.VER This input acts as a CV control for the channel attenuverter, allowing you to dynamically adjust the amplitude and polarity of the signal.
0V results in no modulation, maintaining the current amplitude and polarity. -5V inverts the signal with maximum amplitude.(POL) +5V maintains the signal’s polarity with maximum amplitude. (VCA)
· Logic Operations
/X>Y. Outputs a high signal when the X channel is greater than the Y channel, useful for creating complex modulation or conditional triggers.
/SUM. Outputs the sum of the X and Y channels, combining both signals into one.
/OR. Outputs the higher voltage of X or Y channels.
/AND. Outputs the lower voltage of X or Y channels.
ARC

X LOOP Y
X ATT·VER Y Fig.19 Detail of Loop & Attenuverter CV Inputs

X>Y

SUM

AND

Fig.20 Detail of Logic Outputs

Calibration
ARC is factory calibrated with precision sources. The following procedure is for adjusting inaccuracies in your system:
· ATT-VER Center Adjust 1 2
These adjust the center position of the attenuator/offset voltage for Y and X channels. When the potentiometer is centered, the output should be 0V to ensure proper alignment.
· Rise Shape Adjust 3 5
These trimmers adjust the rise curve for the Y and X channels. Calibrate them so that when the shape potentiometer is centered, the rise curve is linear. This ensures a neutral starting point for further adjustments.
· Fall Shape Adjust 4 6
These control the fall curve for the Y and X channels. Set them so that the fall curve is linear when the shape potentiometer is in the center, allowing for smooth modifications.
· V/OCT Tracking Adjust 7 8
These trimmers tune the 1V/Octave tracking for Y and X channels, ensuring accurate response across some octaves range.

2
RT5
5
Y SLOPE RISE SHAPE
RT6
6
Y SLOPE FALL SHAPE
RT4
8
Y SLOPE VOCT TRACKING

RT8
Y SLOPE ATT-VER CENTER

RT7
X SLOPE ATT-VER CENTER

RED

1
RT2
3
X SLO RISE SHAPE
RT3
4
X SLOPE FALL SHAPE
RT1
7
X SLOPE VOCT TRACKING

ARC

Compliance
This device complies to the EU guidelines and is manufactured RoHS conforming without use of led, mercury, cadmium and chrome. Nevertheless, this device is special waste and disposal in household waste is not recommended.
This device meets the requirements of the following standards and directives:
· EMC: 2014/30/EU · EN 55032. Electromagnetic compatibility of multimedia equipment. · EN 55103-2. Electromagnetic compatibility – Product family standard for audio, video, audio-visual and entertainment lighting control apparatus for professional use.
· EN 61000-3-2. Limits for harmonic current emissions. · EN 61000-3-3. Limitation of voltage changes, voltage fluctuations and flicker in public low-voltage supply systems. · EN 62311. Assessment of electronic and electrical equipment related to human exposure restrictions for electromagnetic fields.
· RoHS2: 2011/65/EU · WEEE: 2012/19/EU

ARC

Guarantee
This product is covered by 2 years of guarantee on purchased goods, which begins when you receive your package.
· This guarantee covers Any defect in the manufacturing of this product. Replacement or repair, as decided by NANO Modules.
· This guarantee does not cover Any damage or malfunction caused by incorrect use , such as, but not limited to: – Power cables connected backwards. – Excessive voltage levels. – Unauthorized mods. – Exposure to extreme temperature or moisture levels.
Please contact our customer service – jorge@nanomodul.es – for a return authorization before sending the module. The cost of sending a module back for servicing is paid for by the customer.

Technical Specifications
Dimensions 24HP 120×128,5mm Current +12V 150mA / +5V 0mA / -12V 130mA Input & Output Signals ±10V Min. time for Attack & Decay 0.5ms Max. time for Attack & Decay 7 minutes Impedance Input 10k – Output 10k Materials PCB and Panel – FR4 1,6mm Depth 40mm – Skiff friendly

Contact
Bravo! You have learned the basic fundamentals of your ARC Module.
If you have any doubts, please feel free to contact us. nano-modules.com/contact

Modules are designed and assembled in València.

ARC

Documents / Resources

ARC ARC Nano Modules ARC Function Generator [pdf] User Guide
ARC Nano Modules ARC Function Generator, ARC Nano, Modules ARC Function Generator, ARC Function Generator, Function Generator

References

User Manual

ARC Nano Modules ARC Function Generator User Guide

ARC Nano Modules ARC Function Generator

Specifications

Product Usage Instructions

Powering Up

Description

Layout

Common Section

FAQ

Q: How do I adjust the Rise and Fall times?

Q: What is the purpose of the Logic Section?

Documents / Resources

References

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