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ALT
Quick guide
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Thank you for choosing ALT Quad VCA
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.
REDRED
If you flip over your ALT Quad VCA, you will find the “RED” mark at the PCB power
connector, which must match the colored line on the ribbon cable.
Once you have checked all the connections, you can turn on your modular system.
3.
If you notice any anomalies, turn your system off right away and check again your
4.
connections.
Description
ALT is a Quadruple Voltage-Controlled Amplifier, which is an electronic device
that uses electric power to vary the amplitude of a signal applied to its input
terminals, producing a signal proportional to the control voltage at its output.
The amount of amplification provided by an amplifier is measured by its gain, which
is the ratio of output voltage, current, or power to input. There is no signal processing
in a VCA, just overall volume control.
ALT has 4 channels of voltage controlled amplifiers:
• VCAs 1, 2, 3. Each one is equipped with a GAIN control, and a CV IN Attenuverter.
• VCA 4. GAIN CV IN and the signal normalled to +5V (fully open VCA).
Additionally, the outputs of these channels are cascaded from left to right, allowing
ALT to behave as a four-channel mixer.
ALT
NANO Modules - València 2019 ©
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Layout
This image will clarify the function of each of the elements of the module.
ALT
CV Level
Attenuverter
VCA 1
+-
CV1
CV Input Control
Gain
Signal Level Control
Level Indicator
VCA 2
VCA 3
Signal Inputs
CV 1,2,3 Inputs
Signal Gain Control.
Signal Outputs
Each output is normalled to the
mix input of the adjacent one.
CV2
+-
CV3
1 2 3 4
CV1 CV2 CV3 CV4
1 2 3 4
+-
VCA 4
This VCA can be
controlled by CV4 Input.
CV4 Input
Signal Gain Control.
This CV input is normalled
to 5V (fully open VCA).
ALT
NANO Modules - València 2019 ©
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Controls
ALT has a linear response: the amplification
is in direct linear proportion to the control
voltage input (see Fig. 1).
• GAIN
This control sets the initial level of
amplification. This value is summed to the
CV applied at the CV input. The maximum
bias is 5V which provides a gain of 1.
(see Fig. 1)
At minimum level with no CV present,
there is no signal at the VCA’s output. Once
the gain control is turned up, amplification
occurs (see Fig. 2), even if there is no CV
input present.
The gain control shifts the whole VCA
response upwards.
lin
amplification
voltage control
Fig.1 Response curve for ALT
lin
amplification
• CV
Amplitude attenuverter. Adjusts the amount
and polarity of amplitude modulation from
the CV input.
Inputs & Outputs
• Inputs
/1 - 4
These are the 4 signal inputs of the amplifiers,
which are DC coupled. This means that audio,
CV and trigger signals can be fed here.
/CV 1,2,3
CV inputs for the GAIN of the amplifiers, which
can be controlled with its CV attenuverters.
The voltage is summed with the bias control.
The VCA is fully open with 5V CV, and clips
voltages above this level.
gain
voltage control
Fig. 2 Effect of GAIN control on VCA response
1 2 3 4
CV1 CV2 CV3 CV4
1 2 3 4
/CV 4
This CV input is normalled to internal 5V (fully
open VCA) and can be controlled with any
external voltage.
ALT
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• Outputs
/1 - 4
These are the 4 signal outputs of each
amplifier, which are cascaded from left to
right, allowing ALT to behave as a
four-channel mixer with the ability to
extract any channel from the mix.
ALT as a mixer
When no patch cable is plugged into an
output, the signal from this channel is
cascaded to the next channel. For example,
when no patch cable is patched into output 1,
output 2 will contain the sum of channel 2
and channel 1. If nothing is patched into
outputs 1, 2 and 3, output 4 will contain the
sum of all four channels.
To extract a signal from the mix, plug a patch
cable in the output of the desired channel.
1 2 3 4
CV1 CV2 CV3 CV4
1 2 3 4
ALT
NANO Modules - València 2019 ©
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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
ALT
NANO Modules - València 2019 ©
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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 - [email protected] - 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 8HP 40x128,5mm
Current 58 mA +12V / 31 mA -12V / 0 mA +5V
Input & Output Signals between ±10V
Impedance Input 47k - Output 1k
Materials PCB and Panel - FR4 1,6mm
Depth 20mm - Skiff friendly
Modules are designed and assembled in València.
ALT
Contact
Bravo!
You have learned the basic
fundamentals of your ALT Module.
If you have any doubts, please feel free
to contact us.
nanomodul.es/contact
NANO Modules - València 2019 ©
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