Intellijel Quadratt 1U User manual
Quadratt 1U Manual
Quadratt 1U
Quad attenuator, attenuverter, mixer and DC voltage source
Manual Revision: 2018.05.16
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
Page 1
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.
Plug your S&H output into Quadratt’s ChannelB 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
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Quadratt 1U Manual
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 OutputA, OutputB 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 ChannelA and the
output of Quadratt’s Channel B into your filter’s frequency CV input. Use ChannelA’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 AandB
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 ChannelA, another into ChannelB, and so on. Plug
only Output D into your audio amplifier. Slowly rotate ChannelA’s attenuator clockwise
and you’ll hear the oscillator connected to ChannelA. Slowly turn Channel B’s attenuator
clockwise, and you’ll hear a mix of the two oscillators. Use ChannelC and ChannelD’s
attenuators to add their corresponding oscillators to the mix.
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Quadratt 1U Manual
Installation
This module is designed for use within an
Intellijel-standard 1U row, such as
contained within the Intellijel 4U and 7U
Eurorack cases. Intellijel’s 1U specification
is derived from the Eurorack mechanical
specification set by Doepfer that is
designed to support the use of lipped rails
within industry standard rack heights.
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.
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