Intellijel Quadratt 1U User manual

Quadratt 1U Manual
Quadratt 1U
Quad attenuator, attenuverter, mixer and DC voltage source
Manual Revision: 2017.10.03
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Quadratt 1U Manual
Table of Contents
Table of Contents
Overview
Usage Examples
Installation
Before Your Start
Installing Your Module
Front Panel
Controls
Inputs & Outputs
Technical Specifications
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Quadratt 1U Manual
Overview
Quadratt is a four channel active/buffered attenuverter and summing mixer.  Each channel has
a knob, which can function as a unipolar attenuator or a bipolar attenuverter, depending on the
setting of its corresponding two-position switch.
Each input is normalled to a precision +5V DC voltage source. With nothing plugged into the
jacks, each knob controls a voltage range of 0 to +5 v or  -5 to +5 v depending on the position of
the mode switch.
Each output is normalled to mix into the channel to its right making it possible to do sub mixes in
groups of 2, 3 or all four channels.
Usage Examples
This humble collection of simple parameters provides a wealth of useful functions to the
modular synthesist. Here are some basic examples of how you might employ Quadratt in your
patches:
●Attenuation: Assume you want to subtly   modulate filter resonance, but your filter of
choice doesn’t have a built-in attenuator on its resonance CV input. If you plug the
output of your LFO directly into the resonance CV input on your filter, you’ll be
modulating it at full amplitude — meaning your LFO will be cycling the resonance
between “none” to “ear shattering squelch” and back again. But what if you just want
resonance to undulate a little bit? Quadratt to the rescue!
Plug the output of your LFO into one channel of the Quadratt, then plug the output of
that channel into your filter’s resonance jack. You’ll now be able to “dial down” the
peak-to-peak amplitude of the LFO using the Quadratt’s corresponding attenuator knob.
●Inversion: Assume you want to control a module with an envelope. Normally, voltage
increases during the attack section of an ADSR, then decreases during the decay or
release segment. But what if you want the inverse? What if you want some sonic
attribute to get more   pronounced as the signal decays, not less? For this you need to
invert the envelope. Once again, Quadratt to the rescue!
Plug the output of your envelope into one channel of the Quadratt, set that channel’s
polarity switch to +/-, then turn the corresponding attenuator knob counterclockwise past
12:00 — an inverted envelope now appears at Quadratt’s corresponding output.
●Voltage Offsets: Assume you have a Sample & Hold module sending random notes to
an oscillator, only you want to constrain that unruly 10+ octave range of notes to just one
or two octaves in the bass. One way to do this is to use two channels of a Quadratt.
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Quadratt 1U Manual
Plug your S&H output into Quadratt’s Channel B and the output of Channel B into your
oscillator, then use the Channel B attenuator to limit the range of notes to an octave or
two. Next, use Quadratt’s Channel A (into which nothing is connected) to negatively
offset the note range down into the bass frequencies. Do this by setting Channel A’s
polarity switch to +/-, then turning the corresponding attenuator knob counterclockwise
past 12:00. Because nothing is plugged into Quadratt Output A, Output B contains a
sum of Channels A and B, giving you both the reduced note range and the low
frequencies you desire.
●CV Mixing: What if you want to modulate some parameter with more than one control
voltage at a time? Perhaps you want to send a square wave to modulate a filter’s cutoff
frequency giving it a steady “pulsing” sound while simultaneously sweeping it with a
slow, triangular LFO so that the pulsing sound rises and falls over time. Again, Quadratt
is on the case. And, once again, you’ll be using two channels.
Plug the square wave output of the “pulsing” LFO into Quadratt’s Channel A and the
output of Quadratt’s Channel B into your filter’s frequency CV input. Use Channel A’s
attenuverter to set the amount of pulse you want to hear. Next plug the triangle wave
output of the “slow sweeping” LFO into Quadratt’s Channel B. The output of Channel B
is already connect to your filter frequency and it contains of sum of Quadratt’s A and B
channels. Use Channel B’s attenuverter to set how much the pulse sweeps up and down
the frequency band. You now have two different CV sources controlling one destination.
Want more? Quadratt does have 2 more channels available...
●Audio Mixing: Audio is a voltage too. So you’re probably asking yourself, “can I use
Quadratt to mix multiple channels of audio   together as well?” Yes, you can!
Set all of Quadratt’s polarity switches to UNI and turn all its knobs fully counterclockwise.
Plug the output of one oscillator in Channel A, another into Channel B, and so on. Plug
only Output D into your audio amplifier. Slowly rotate Channel A’s attenuator clockwise
and you’ll hear the oscillator connected to Channel A. Slowly turn Channel B’s attenuator
clockwise, and you’ll hear a mix of the two oscillators. Use Channel C and Channel D’s
attenuators to add their corresponding oscillators to the mix.
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Quadratt 1U Manual
Installation
Intellijel Eurorack modules are designed to be used with a Eurorack-compatible case and power
supply.
Before Your Start
Before installing a new module in your case you must ensure your case’s power supply has
sufficient available capacity to power the module:
● Sum up the specified +12V current draw for all modules, including the new one. Do the
same for the -12 V and +5V current draw. The current draw will be specified in the
manufacturer's technical specifications for each module.
● Compare each of the sums to specifications for your case’s power supply.
● Only proceed with installation if none of the values exceeds the power supply’s
specifications. Otherwise you must remove modules to free up capacity or upgrade your
power supply.
You will also need to ensure you have enough free space (hp)  as well as free power headers in
your case to fit the new module.
You can use a tool like ModularGrid to assist in your planning. Failure to adequately power your
modules may result in damage to your modules or power supply. If you are unsure, please
contact us before proceeding.
Installing Your Module
When installing or removing a module from your case always turn off the power to the case and
disconnect the power cable. Failure to do so may result in serious injury or equipment damage.
Ensure the 10-pin connector on the power cable is connected correctly to the module before
proceeding. The red stripe on the cable must line up with the -12V pins on the module’s power
connector. The pins are indicated with the label -12V, a white stripe next to the connector, the
words “red stripe”, or some combination of those indicators.
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Quadratt 1U Manual
Most modules will come with the cable already connected but it is good to double check the
orientation. Be aware that some modules may have headers that serve other purposes so
ensure the cable is connected to the right one.
The other end of the cable, with a 16-pin connector, connects to the power bus board of your
Eurorack case. Ensure the red stripe on the cable lines up with the -12V pins on the bus board.
On Intellijel power supplies the pins are labelled with the label “-12V” and a thick white stripe:
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Quadratt 1U Manual
If you are using another manufacturer’s power supply, check their documentation for
instructions.
Once connected, the cabling between a module and power supply should resemble the picture
below:
Before reconnecting power and turning on your modular system, double check that the ribbon
cable is fully seated on both ends and that all the pins are correctly aligned. If the pins are
misaligned in any direction or the ribbon is backwards you can cause damage to your module,
power supply, or other modules.
After you have confirmed all the connections, you can reconnect the power cable and turn on
your modular system. You should immediately check that all your modules have powered on
and are functioning correctly. If you notice any anomalies, turn your system off right away and
check your cabling again for mistakes.
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Quadratt 1U Manual
Front Panel
Controls
1. Channel A attenuator
Sets the amount of attenuation for the IN A input. The behaviour of the knob depends on
the position of the corresponding polarity switch. The attenuation amount is linear.
2. Channel A polarity switch
This is a 2-position switch that sets the polarity of the OUT A signal.
With the switch in the left UNI position the channel functions as a standard attenuator.
OUT A outputs the unmodified signal from IN A when the attenuator knob is fully
clockwise, and it outputs no signal (0 V) when the knob is fully counterclockwise.
With the switch in the right +/- position the channel acts a bipolar attenuverter. The
output is the unmodified input with the knob fully clockwise, the inverse of the input with
the knob fully counterclockwise, and 0 V when the knob is at the 12 o’clock position.
3. Channel B attenuator
Behaves the same as the Channel A attenuator but for channel B.
4. Channel B polarity switch
Behaves the same as the Channel A polarity switch but for channel B.
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Quadratt 1U Manual
5. Channel C attenuator
Behaves the same as the Channel A attenuator but for channel C.
6. Channel C polarity switch
Behaves the same as the Channel A polarity switch but for channel C.
7. Channel D attenuator
Behaves the same as the Channel A attenuator but for channel D.
8. Channel D polarity switch
Behaves the same as the Channel A polarity switch but for channel D.
Inputs & Outputs
A. IN A
Input for channel A.
With no cable plugged in, Quadratt sends a 5V DC voltage into Channel A, which you
can attenuate (or invert) with the Channel A attenuator knob. For example, with nothing
plugged into Channel A and the Channel A knob fully clockwise, 5V is sent out channel
A. If the Channel A knob is fully counterclockwise and its polarity switch is set to UNI,
then 0V is sent out Channel A. if the Channel A knob is fully counterclockwise and its
polarity switch is set to +/-, then -5V is sent out Channel A.
B. IN B
Input for channel B. With no cable plugged in, Quadratt sends 5V into Channel B, which
you can attenuate (or invert) with the Channel B attenuator knob.
C. IN C
Input for channel C. With no cable plugged in, Quadratt sends 5V into Channel C, which
you can attenuate (or invert) with the Channel C attenuator knob.
D. IN D
Input for channel D. With no cable plugged in, Quadratt sends 5V into Channel D, which
you can attenuate (or invert) with the Channel D attenuator knob.
E. OUT A
Output for channel A, which is the attenuverted value of IN A.
F. OUT B
Output for channel B, which is the attenuverted value of IN B. With no cable connected
to OUT A, this jack outputs the sum of channels A and B.
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Quadratt 1U Manual
G. OUT C
Output for channel C, which is the attenuverted value of IN C. With no cable connected
to OUT A or OUT B, this jack outputs the sum of channels A, B and C. Plugging a cable
into OUT A removes it from OUT C, meaning OUT C = OUT B + OUT C. Plugging a
cable into OUT B removes both OUT A and OUT B from OUT C.
H. OUT D
Output for channel D, which is the attenuverted value of IN D. With no cable connected
to OUTS A, B or C, this jack outputs the sum of channels A through D. Plugging a cable
into OUT A removes it from OUT D, meaning OUT D = OUTS B + C + D. Plugging a
cable into OUT B removes both OUT A and OUT B from OUT D, meaning OUT D =
OUT C + D. Plugging a cable into OUT C removes OUTS A through C from OUT D.
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Quadratt 1U Manual
Technical Specifications
Width
28 hp
Maximum Depth
25 mm
Current Draw
24 mA @ +12V
23 mA @ -12V
Page 10