Kassutronics Quantizer User manual

Quantizer user manual Kassutronics
Version 1.1 October 15, 2019
Schematics, PCB layout and documentation c  2019 Caspar Ockeloen-Korppi.
Introduction: what is a quantizer?
A typical modular VCO accepts control voltage in the V/Oct scale, meaning that steps of ± 1V
will change the frequency up or down one octave. To play consecutive semitones on a VCO,
you must feed it a voltage increasing in steps of
1
12
V, or 83 mV, since there are 12 semitones
in an octave.
In it's basic form, the quantizer is a module which takes in any voltage and rounds it to
the nearest
1
12
V, allowing your VCO to always play in tune. To make the quantized notes
even more musical, the Quantizer allows you to dene which semitones are allowed with the
scale buttons. More advanced features such as transpositions, chords and CV control will be
discussed later in this manual.
Module overview
Quantizer
Gate A GateTrigTrig
Out BIn Out
In
1
1
2
0
4
1
5
1
0
7
6
8
Shift
A
B
τ
Scale buttons
Function buttons
Quantizer channel 2
Control voltage inputs
Quantizer channel 1
The interface of the quantizer is built around a ring of 12 buttons that dene the quantiza-
tion scale, and four function buttons. The
τ
Shift
button gives access to extra button functions
labeled in blue. For example, pressing
τ
Shift
+ button 6 opens the keyboard mode . Pressing
will return from any menu to the normal display.
User manual version 1.1 1

Quantizer Kassutronics
Getting started
Basic connections
To start, connect some voltage source to the In jack of channel 1. This could be an LFO,
sequencer, ribbon controller, or any other CV source. Connect the Out jack to the V/Oct
input of a VCO. Now, the VCO will play in tune to the active scale, which by default is a
major scale.
Each time the input voltage changes enough for the Quantizer to change the note, the Gate
output will go high and the corresponding LED will ash. The Gate output is typically used
to trigger an envelope.
The Trig input can optionally be fed with any gate or trigger signal. Once a cable is
connected to this input, the quantizer will only output a new note when there is a rising edge
on the Trig input. Among other things, this is useful for connecting the trigger or gate output
of a CV keyboard or ribbon controller. When the cable is removed from the Trig jack, the
quantizer will automatically go back to the normal freerunning mode after about one second.
Setting the quantization scale
Use the scale buttons to dene the musical scale  the quantizer will only allow notes
which enabled (button LED on) to be played. The 12 scale buttons correspond to the
12 semitones in an octave. They are arranged in a circle to emphasize the circular
nature of musical pitch: going up 12 semitones gives you the same note, but one octave higher.
Usually, the top button (labeled 0) is seen as the root note of the scale. The scale buttons
are also surrounded by white and black regions, which correspond to the white and black keys
of the piano keyboard assuming button 0 is a C. So, enabling only the white buttons (which is
the default setting) gives you a major scale.
Rotation: everything is circular
τ
While the white and black keys are useful if you are used to a piano keyboard, I think
the circle gives a more natural insight into many aspects of musical theory. Once you
have set up a scale you like with the scale buttons, try using the rotate buttons
and to rotate the scale in steps of one semitone.
The eect of rotating a scale can be seen in two ways. In one view, the rotated scale is
the same scale with a dierent root note. For example, rotating a C major scale clockwise 3
semitones gives an E [ major scale. Alternatively, a rotated scale can be viewed as a dierent
scale but with the same root note. Using the same example, C major rotated clockwise 3
semitones is a C minor scale. Which of these views is relevant depends on the musical context
where it is used.
In addition to using the rotate buttons, you can also use the rotate menu to rotate to a
specic note. Press
τ
Shift
+
τ
to enter the menu, and press one of the 12 scale buttons to
rotate the root note to that location.
Keyboard mode
There is one special mode where the quantizer stops it's normal quantizing business:
keyboard mode. It is activated by pressing
τ
Shift
+ . In keyboard mode, the 12 scale
buttons act like a CV keyboard, and the last pressed note is output on both channels.
2 User manual version 1.1

Kassutronics Quantizer
The octave can be changed with the and buttons. This mode is particularly useful when
tuning your oscillators.
Gate length
Press
τ
Shift
+ to enter the gate length menu. The gate length can now be set with
the buttons 0 through 11, where 0 corresponds to a very short gate of 1 ms, and 11
corresponds to a gate length of 2 seconds.
Legato mode
By default the quantizer is in staccato mode, where it ensures the gate always briey
turns o between two notes. To turn on legato mode, press
τ
Shift
+ . Now, the
gate will not retrigger if it was still on from the previous note. Typically this is only
noticeable with longer gate lengths.
User manual version 1.1 3

Quantizer Kassutronics
Transposition and osets
By default, the quantizer simply rounds the incoming voltage to the nearest enabled note, so
with a 0V input you will get a 0V output. The transpose and oset features are two dierent
ways to alter this behavior. The following block diagram shows the operation of the quantizer
algorithm.
In Out
Gate
Quantize
Rotate
Oset Transpose
Trigger
Oset
The oset adds any number (postive or negative) of semitones and octaves to the
input signal before it is quantized. This makes the pitches go up or down while still
quantizing them to the original scale.
Press
τ
Shift
+ to go to the Oset both menu. Using the buttons 0 to 11 adds an oset
of 0 to 11 semitones, and the buttons and add or subtract a whole octave. This is applied
to both channels at once.
Similarly, press
τ
Shift
+ to go to the Oset channel 2 menu. Any oset programmed
here is only applied to channel 2.
Transpose
τ
The transpose function adds any number of semitones and octaves to the output signal
after it is quantized. This not only makes the pitches go up or down, but also changes
the musical scale of the output.
Press
τ
Shift
+
τ
to go to the Transpose both menu. The transposition set here is applied
to both channels at once.
Similarly, press
τ
Shift
+ to go to the Transpose channel 2 menu. Any transposition
programmed here is only applied to channel 2.
4 User manual version 1.1

Kassutronics Quantizer
CV (almost) everything!
The Quantizer module has two control voltage (CV) inputs, labeled A and B, that can be
assigned to almost all parameters of the Quantizer. This allows dynamically changing the
scales in dierent ways to create chord or scale progressions in the music, as well as changing
the gate length.
To assign one of the CV inputs, enter the CV menu by pressing either
τ
Shift
+
A
or
τ
Shift
+
B
. Then, press the button corresponding to the function you want to put under CV control.
The following buttons can be chosen:
Gate length (not yet implemented)
τ
Rotate scale
τ
Transpose both channels
Transpose one channel (CV A transposes channel 1, CV B transposes channel 2)
Oset both channels
Oset one channel (CV A osets channel 1, CV B osets channel 2)
Load scale
CV input specications
For most functions, the CV inputs are 1V/Oct inputs, internally quantized to the nearest
semitone. For the Rotate , Transpose and Oset functions this means you can connect any
V/Oct CV source to program these functions. For example, connecting a CV keyboard to the
Rotate function allows you to play a chord sequence  the root note will be set to the key
pressed on the keyboard.
For the Load function, the input also follows the V/Oct standard, but now each note on
the CV keyboard corresponds to a dierent slot in memory. More technically, the input works
in steps of 83 mV. For example, a CV of 0.0 V loads slot 0, 0.083 V loads slot 1, 0.166 V load
slot 2, and so on. When you reach 1 V it wraps around to slot 0 again.
For the Gate length function a CV of 5V corresponds to the full scale of gatelengths
accessible through the gatelength menu. The CV value is added to the menu setting, and
where positive CV voltages lengthen the gate, and negative CV voltages shorten the gate.
Tip: The CV control of gate length is continuous, and allows much ner changes in length
than the 12 possibilities in the gate length menu.
User manual version 1.1 5

Quantizer Kassutronics
Load/Save
Autosave
The Quantizer automatically remembers all settings and the currently active scale, and restores
to the same state where you left o on powerup.
1
Load/Save scales
There are 12 slots for saved scales, represented by the 12 scale buttons.
To save the current scale, press
τ
Shift
+ . The button will ash, and the scale
buttons light up to show the memory contents: empty slots are o, and used slots are
lit. Press the scale button corresponding to the slot you want to save in. Alternatively, press
the key to cancel.
To load a saved scale from memory, press . Again, the scale buttons light up to show
which slots have any data in them. Press the button from which you want to load the scale,
or press to cancel.
1
To avoid excessive wear of the EEPROM memory, data is saved 10 seconds after the last time any relevant
button was pressed.
6 User manual version 1.1

Kassutronics Quantizer
Advanced settings
Quantization mode
This setting aects the detail in how an incoming note is handled when it does not t
in the selected scale. Enter the settings menu by pressing
τ
Shift
+ , and choose one
of the following modes with the corresponding scale button:
0 Nearest note . This is the default mode. The incoming voltage will allways be quantized
to the nearest note that is enabled. This mode is best suited with random / unquantized
voltage sources.
1 Skip . In this mode the quantizer will ignore the note if it is not enabled in the scale, even
when receiving a trigger input. The gate output will also not be red. This mode can be
useful when the incoming voltage source is already quantized to 1V/Oct. For example
when playing a CV keyboard, pressing keys not in the current scale will be ignored.
2 Equally distributed . In this mode the enabled notes in the scale are distributed equally
over the octave. For example, if 4 notes are enabled, each note will get an equal 0.25 V
range of input voltages. This mode is can be useful when using a continuous voltage
source such as a ribbon controller, or when quantizing a random voltage source. In the
latter case this mode makes sure each note will appear equally likely.
Trigger delay
τ
Normally, the Quantizer responds nearly immediately when a trigger is detected on
the Trig input. However, sometimes the voltage source connected to the In input
needs a bit of extra time to stabilize. The trigger delay function can be used to add a
variable delay up to 11 ms between receiving the trigger and sampling the input voltage.
Press
τ
Shift
+
τ
to enter the trigger delay menu. Press the scale buttons 0 through 11 to
vary the trigger delay between 0 and 11 ms, respectively, where 0 means no delay.
The trigger delay is particularly useful with some sequencers and CV keyboards that send
a trigger/gate signal before the V/Oct output is updated. For example the Arturia Keystep
and Beatstep range typically needs around 5 ms trigger delay to function properly.
Trigger delay has no eect in free running mode.
Further information
Check for updated documentation and other information on my blog at kassu2000.blogspot.com.
I am always happy to answer questions and receive feedback at k[email protected].
User manual version 1.1 7