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Description
Tone is a quad, voltage controlled filter with low pass and band pass outputs. Its four
channel architecture enables the intuitive patching of shimmering, polyphonic textures.
The 24dB slope provides a warm, buttery character. Self oscillation allows each
channel to double as a sine wave oscillator with v/oct tracking across four octaves.
Cascade OTA topology. A perfect match for the Chord.
- Quad voltage controlled filter
- 24 dB slope
- Simultaneous low pass and band pass outputs
- Self oscillation with v/oct tracking across four octaves

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Table of Contents
Installation/Specifications 4
Tone 5
General Functions Overview 6
Calibration 7

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Installation
To install, locate 18 HP of space in your Eurorack case and confirm the positive 12
volts and negative 12 volts sides of the power distribution lines. Plug the connector
into the power distribution board of your case, keeping in mind that the red band
corresponds to negative 12 volts. In most systems, the negative 12 volt supply line is
at the bottom. The power cable should be connected to the Tone with the red band
facing the bottom of the module.
Specifications
Format: 18 HP Eurorack module
Depth: 23mm (Skiff Friendly)
Max Current: +12V = 91mA
-12V = 87mA

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General Functions Overview
1. In:
Audio input
Range: 10Vpp
2. CV:
Control voltage input for Frequency
Control voltage is added to the knob position and scaled by the Frequency
Attenuverter knob
Tone will track 1V/oct for up to four octaves
Range: ±10V
3. Fre quency Attenuverter:
Attenuverter that sets the attenuation and inversion of the signal present at the CV
input
If the knob is clockwise, positive voltage will add to the knob position and negative
voltage will subtract from the knob position.
If the knob is far counterclockwise, positive voltage will subtract from the knob position
and negative voltage will add to the knob position
4. Frequency:
Sets the cutoff frequency of the filter
Also known as the corner frequency, or -3dB down point
5. Resonance:
Sets the resonance, or “Q” of the filter
When fully clockwise, the Tone will self-oscillate and output a very pure sine tone
whose pitch is determined by the Frequency knob

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6. LP:
Lowpass filter output
7. BP:
Bandpass filter output
Controls 1-7 are replicated on channels 2-4
Calibration
There is one V/oct trimmer per channel on the back side of the module that is used for
calibrating the CV tracking of the cutoff frequency.
A small flathead screwdriver is needed for calibration.
Turning the trimmer clockwise will truncate the range.
Turning the trimmer counter-clockwise will expand the range.