Snyderphonics JD-1 Custom Keyboard/Sequencer Reference

Snyderphonics JD-1 Custom Keyboard/Sequencer Reference
Snyderphonics JD-1 Custom Keyboard/Sequencer
Reference Manual
Power Supply
The power supply provided is a triple output desktop supply, with +5V, +15V and -15V
outputs. The connector is a 5-pin DIN circular connector. The power input jack is on
the left side of the wooden case, and the toggle switch next to it turns the keyboard on
and off (up is on, down is off).
Ground Connection
The black banana jack on the side of the wooden case next to the power supply and
on/off switch is a GND connection. When using the JD-1 to control an analog
synthesizer, connect this GND jack to your synthesizer with a banana cable.
FEATURES:
Keyboard
The keyboard is made up of 32 anodized aluminum keys that operate as capacitive touch
sensors.
Knob Banks A ad B
There are 64 knobs above the keyboard, organized into two knob banks, labeled A and B.
Each key has an A knob (top), and a B knob (bottom).
Joystick
The joystick is a spring return Doepfer-style joystick. The aluminum joystick lever is
included in a Ziploc bag wrapped with the power supply. I’ve also included the plastic
lever that came with the joystick. The joystick sends X and Y values from 0-5V, with the
center at around 2.5V. The knobs near the joystick outputs can scale this output down.
Pitch CV Outputs
There are four pitch CV outputs, colored blue and labeled “P”, for voice 1, 2, 3, and 4.
These produce voltages from 0-10V, with 16-bit precision. These outputs are designed
to produce musical pitches, based on a 12-note scale. The tuning of these pitches is
effected by the V/Oct scaling (1.0V or 1.2V, default is 1.2V), the Fine Scaling (from 0200, 100 is no scaling), and the Tuning setting (which selects between 12-note tunings,
such as Equal Temperament and Meantone). When in monophonic keyboard mode,
the first two pitch outputs produce the same pitch, while the third and fourth output
“Ribbon Controller” information – see below for those specifications. When in
sequencer mode, all four pitch outputs send the same information. When in 2 note or 4
note polyphony keyboard mode, the different pitch outputs send the voltages for the
different voices.
Surface-Area CV Outputs
There are four surface-area CV outputs, colored green and labeled “V”, for voice 1, 2, 3,
and 4. These outputs produce voltages from 0-10V, with 12-bit precision, and 10ms
analog smoothing. They are designed so that covering as much surface area as it is
generally possible to cover will produce an output of around 8V. These outputs can be
scaled down with the use of the knob that is mislabeled “scale all”. When in monophonic
keyboard mode, voices 1 and 2 are the same voltages, and 3 and 4 output nothing. When
in sequencer mode, all four voices show the same value. When in 2 or 4 voice polyphony,
the voices each show the value that corresponds to its respective polyphony voice.
Knob A and B Outputs
There are four Knob A outputs, and four Knob B outputs, all of which are colored
purple, one of each for voices 1, 2, 3, and 4. The Knob A outputs correspond to the
values of knobs in the A knob bank, and the Knob B outputs correspond to the values of
knobs in the B knob bank. These outputs can be scaled with the “scale A” and “scale B”
knobs, respectively. When the scale A and scale B knobs are fully clockwise, the knobs
will output values between 0-10V, in 12-bit resolution. When in monophonic keyboard
mode, voices 1 and 2 report the same values, and voices 3 and 4 are unused. When in
sequencer mode, all four voices report the same values. When in 2 or 4-voice polyphony,
the voices reflect the knob values of the polyphony voice. When the
“combined/independent” setting is changed from “independent” to “combined”, the A
knob is fine-tuned by the value of the B knob, and is not affected by the “scale A” knob.
The B output operates normally in “combined” mode.
Gate and Trigger Outputs
Each of the four voices has one Gate (really a gate+trigger), and one Trigger output. The
top jack is the Gate, and the bottom is the Trigger. The behavior of these outputs
depends on the “gate style” setting. When in Buchla style (the default), the Gate output
will pulse at 15V for around 10us, then fall to 7V and hold until a release happens. The
Trigger will pulse at 15V for 20us, and then fall to ground immediately. In Euro style,
the Gate output will rise to 7V, then hold until a release happens, and the Trigger pulses
at 7V and then falls to ground. In Moog style, the outputs hold at 7V in their off state,
and the Gate outputs stays at ground through the duration of a note, while the Trigger
pulses at ground and then rises immediately back to 7V.
Sequencer/Keyboard button
This button changes the JD-1 from operating in keyboard mode, where the user plays the
keyboard with monophonic or polyphonic handling, to sequencer mode, where the JD-1
steps through stages when it receives a clock pulse, and the user can guide this sequencer
action using the keyboard.
Transpose Selector
This rotary encoder allows the performer to alter the pitch of the “P” outputs up or down
by up to 12 semitones. An indicator light shows when the transpose value is non-zero,
and the LCD display shows the current transpose value with the marking “Tr=”.
Sequencer Mode Selector
When in sequencer mode, the rotary encoder determines how the sequencer steps. The
options are “left-to-right”, “right-to-left”, “back-and-forth”, and “random”.
Quantize/Range Button
When in sequencer mode, this button determines how the keyboard interacts with the
step sequencer. In Range mode (the default), pressing two keys will set the range within
which the step sequencer can step. When in Quantize mode, the sequencer will only step
on stages that the user selects by touching them. Quantize mode can also be used as an
arpeggiator.
Mono/Poly Selector
This rotary encoder selects between the polyphony modes when in keyboard mode. The
options are “mono retrigger” (the default), in which each new keypress initiates a new
gate and trigger event, “mono legato”, in which a new gate and trigger event will only
happen after a rest, and 2 and 4-voice polyphony.
Octave Buttons
These buttons allow the performer to raise and lower the pitch output by 2 octaves in
either direction.
Knob Mode (indpendent/combined)
This button switches between “independent” knob mode and “combined” knob mode.
When in “independent” knob mode (the default), the A and B knob outputs are treated
separately, and each is scaled by its associated scale knob. In “combined” mode, the A
output is fine-tuned by the B knob, and also is not scaled by the “scale A” knob. The B
knob operates normally. This allows for finer resolution on the A knob, at the expense of
independence of knob control.
Internal Sequencer Clock Speed knob
This knob is mislabeled “waveform” since it was originally intended to be for the internal
synthesizer, which doesn’t exist yet. I put it to use as a speed control for the internal
sequencer clock, which is selected as the sequencer clock by default.
Internal Sequencer Clock Randomness knob
This knob is mislabeled “filter” since it was originally intended to be for the internal
synthesizer, which doesn’t exist yet. I wanted a panel control to add randomness to the
sequencer clock, so I used this knob. Turned all the way counterclockwise, the pulses are
regular and periodic. When turned clockwise, the pulse period becomes increasingly
affected by random values.
Trigger/Gate In
This is the yellow jack, mislabeled as “CV in”. When sequencer clock is set to “external”,
a pulse in this input will cause the sequencer to step. It looks for rising edges.
LCD Display Features
There are several features that I decided to put on the LCD because there weren’t
dedicated buttons for them. I intended to make a menu system, but it doesn’t yet exist,
so I used the menu navigation buttons I designed into the panel, and gave them specific
dedicated roles. Listed below are explanations of the abbreviations on the LCD, with
notes about which buttons control those parameters.
“Gate=”
This is “gate style”. Set it to what you need for the synthesizer you are conrolling.
B=Buchla, E=Euro, and M=Moog. Buchla style will turn the gate outputs into
trigger+gate outputs. Moog uses inverted logic, where the “off” state is logic high. Euro
will work for most modern analog synthesizers that are not Moog or Buchla. This is
controlled by the button marked “store” in the “Program” section of the panel.
“Skip=”
This is the “skip step” feature. This is a probability that any step will be skipped
in sequencer mode. The numbers are from 0-31, with 0 meaning a 0% probability and
32 meaning 100% probability. Therefore, you can consider 16 to be 50%, and with “skip
step” set to 16, any given sequencer clock has a 50% chance of being ignored. This
feature can produce nice syncopations. This parameter is controlled by the rotary encoder
in the “Program” section of the panel.
“Tr=”
This is the Transpose setting. It displays the value set by the “transpose” rotary
encoder.
“S=”
This is the “fine scale” feature. It allows you to tune the V/Oct scaling slightly if a
synthesizer you are using doesn’t respond correctly to exactly 1V or 1.2V per octave. 100
means no scaling, and the range is from 0-200. Try playing a note in several octaves
(push the octave button up and down) and if it seems to be playing sharp or flat octaves
on the synthesizer you use, try tuning it with this parameter. It is controlled by the up
and down buttons in the “Program” section of the panel.
“C=”
This is the Sequencer Clock Mode. It is either “I” for internal (default), or “E”
for external. When set to internal, the sequencer steps on its own, with the speed defined
by the internal sequencer speed knob. When set to external, it looks for a trigger pulse on
the yellow “Trigger/Gate In” jack. This is controlled by the button marked “Enter” on
the “Program” section of the panel.
“Tun=”
This is the Tuning parameter. There are five tuning tables in memory. Each of
them is a slightly different twelve-note scale. They are “Equal Temperament”, “Just
Tuning”, “Kora”, “1/4 Comma Meantone”, “Werckmeister Well-Temperament I”, and
“Werckmeister Well-Temperament III”. Pressing the “left” button in the “Program”
section of the panel selects between these scales.
“V/O=”
This is the “volts per octave” parameter. It is 1.2V/oct by default, but can be
changed between 1.2V and 1V per octave by pressing the “right” button on the
“Program” section of the panel.
MIDI Out
The JD-1 sends MIDI messages out the MIDI out jack. In monophonic keyboard mode
or sequencer mode, everything will be on MIDI channel 1. In the polyphony modes,
MIDI channels correspond to polyphony voices (using channels 1-4). Additionally, the
A and B knob banks and the surface-area values are sent out as MIDI continuous
controller values. When in polyphony modes, these values also follow the channel
assignments based on polyphony voices. The CC# are listed below:
CC#16 = A knob
CC#17 = B knob
CC#18 = surface-area (V)
Ribbon Controller Output
There is a pseudo ribbon controller built into the firmware of the JD1. It’s somewhat
crude, but can be useful. When in monophonic keyboard mode, a general “white-keycentroid” will be sent out the “P” output of voice 3. This can be used during normal
playing as a basic “where I am on the keyboard” 0-10V output. To use it more directly,
place three fingers close together (index, middle and ring) on the white keys (the
naturals) of the keyboard. Slide these fingers as a group along the keyboard (not using
the black keys). You will get an approximate output of your position on the keyboard.
There is another processed version of this value that appears on the “P” output of voice 4.
In this output, it is scaled to be in the actual voltage range that the pitch output of the
keyboard would put out, and it responds to the octave and transpose controls. Note that
in this mode, only the “white keys” are understood. You can play a “black key” by
pressing two white keys – they will average to be the pitch of the black key between them.
This is just a little extra feature I worked up, and I haven’t found this particularly useful,
but it’s kind of interesting.
Not Implemented
Several panel elements are not yet implemented. The “portamento” knob does nothing –
external analog processing must be used for portamento effects. The USB and Ethernet
ports are currently non-functional. The MIDI In jack is not connected or implemented
in software. The black banana jack on the front panel is intended as a CV input (though
mislabeled as “gate in” but it isn’t currently implemented. The audio output jack is
currently not implemented.
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