Dr Scientist DUSK User manual

DUSK Multi Mode
Low Pass
Filter
Multi Stomp:
CUT Mode: Hold for filter sweep.
ENV Mode: Hold to freeze filter.
LFO Mode: Press for Tap Tempo.
Hold to ramp rate down.
1/4” Exp and CV Jack:
Use TR cable for exp,
any resistance.
Use T cable for
0-5V CV.
5 Pin DIN MIDI IN Jack:
Control all of Dusk's
digital features (Filter knob,
Modes, Alt features, Clock,
Multi and Bypass stomps,
and Presets with standard
MIDI CC and PC messages.
Mode Pu hbutton:
CUT: Manual mode,
control filter with Filter knob,
Exp/CV, or MIDI.
ENV: Envelope mode, filter
responds to input dynamics.
LFO: Low Frequency Osc
mode, drive filter with 6
waveforms, tap in rate.
Bypa Stomp:
Press for True Bypass.
Hold to load and cycle
Through 4 on board
presets.
FILTER Knob:
Digital control over an
analog OTA based
12dB/Oct LPF.
Input, Output, Power
9VDC, centre neg,
2.1mm x 5.5mm barrel,
150mA.
Analog Re onance and
Volume controls. (Res
trimpot on PCB for fine
tuning of max feedback)
Alt Feature Pu hbutton:
CUT Mode: low, Med,
Fast rates for manual
filter sweep (hold Multi).
ENV Mode: Reverse
Direction of envelope
sweep, Up or Down.
LFO Mode: Choose from 6
waveforms for auto LPF.

Dusk Multi Mode Low Pass Filter
Hello and thank you very much for purchasing this Dusk! We really appreciate it and we hope
you have a ton of fun with your new pedal! Please check out our Dusk playlist at
www.youtube.com/drscientistsounds to see more examples of using the pedal. Email us
[e-mail] if you have any questions at all and check out www.drscientist.ca for other
goodies.
The Brief – Dusk is a digitally controlled analog filter. At its heart is an analog 12dB/Octave low
pass filter based around an old school integrated circuit called an Operational Transconductance
Amplifier or OTA. The OTA runs off of split +/-9V rails for great audio quality and a deep filter
sound. The digital side brings a whole bunch of convenient and powerful features like controlling the
filter setting tap tempo MIDI 6 LFOs and a platform for all the best filter modes in one small pedal.
The Power – 9VD , 150mA, centre negative 2.1mm plug. We recommend you use a quality
isolated filtered and regulated supply and be careful with daisy chaining or you could have hum.
Email us if you need any power supply help! (There's no battery inside).
The Jacks – The Input and Output are located on the top panel and have arrow indicators showing in
and out. On the left side of the pedal there's a standard 5 Pin DIN jack for MIDI Input. On the right
side of the pedal there's a 1/4” jack for Expression/Control Voltage Input.
The Filter Knob – This knob controls the position of the filter in each Mode. In UT Mode this is
your main frequency cutoff control. With the Filter knob all the way up the filter is fully open with
the knob all the way down the filter is fully closed. In ENV Mode you can limit the range of the filter
sweep turn the knob up or down to keep the filter movement in that range. In LFO Mode you use the
Filter knob to set the range of the filter sweep. Leave it at noon for maximum LFO depth turn it up or
down to keep the LFO movement in that range.
The Resonance Knob – This controls how much of the output signal is fed back into the input of the
filter. Resonance adds an interesting tonal quality to the filter sweep a sound that pairs well with
sweeping through the frequencies and just sounds cool and filtery. Too much resonance can lead to
feedback a loud howling sound or weird laser sounds which may or may not suit your musical
vision. There's a little blue trimpot on Dusk's PCB that lets you dial in the maximum resonance just
right for your setup and tastes. (It's in the top right corner and says *RES ADJUST* around it).
The Volume Knob – Depending on how you use your filter you might need to raise or lower your
volume to keep your signal at unity or however you like it.
The Left Pushbutton – Chooses between the 3 Filter Modes of Dusk. UT is Manual Mode and this
mode puts you in charge of the filter sweep. You can control the filter with the Filter knob an
expression pedal a control voltage or MIDI messages. ENV is Envelope Mode putting the dynamics
of your playing in control of the filter setting. (There's a little blue trimpot on Dusk's PCB that you
use to adjust the envelope sensitivity to your specific instrument. It's on the left side lower middle
and says *ENVELOPE SENS* around it). LFO mode uses 6 unique sounding digital waveforms to

control the filter setting dynamically. Set the LFO rate by tapping the Multi Stomp or sending MIDI
Beat Clock and/or MIDI subdivisions/multipliers. This button is also used to save the current digital
settings to the current onboard preset. Hold the button for one second and the settings will be saved.
The LED will light up with the colour corresponding to the current preset.
The Right Pushbutton – Chooses the alternate settings for each of the Modes. In UT Mode you
can choose between 3 different sweep rates for the momentary filter sweep feature on the Multi
Stomp. In ENV Mode you can choose the direction of the filter sweep that follows your input signal's
envelope making the filter open or close with your dynamics. In LFO Mode you can choose between
6 different digital waveforms: Sine Ramp Saw Square Sample & Hold and Random.
The Left Stomp – MULTI – Has different roles depending on the Mode. In UT Mode you can hold
down the Multi stomp for a momentary filter sweep. In ENV Mode you can freeze the envelope
momentarily by holding down the Multi stomp. In LFO Mode you use Multi to tap in your tempo or
hold it down to ramp the LFO rate down nice and slow momentarily.
The Right Stomp – BYP – Turns your pedal on and off and you also use it to load and scroll through
the 5 built in presets. Dusk's bypass is True Bypass using a relay and soft touch switch.
The MIDIs – Dusk is shipped set to receive MIDI messages on all channels. You can change the
MIDI channel that Dusk receives MIDI messages on by holding the Right Pushbutton while the pedal
turns on. Then use the two Pushbuttons to scroll up or down to the MIDI channel number you desire
using the MIDI hannel Reference hart on the MIDI Implementation page for reference. When
you have found the desired MIDI channel number press the Byp Stomp to confirm and select the new
MIDI channel number. If you wish to exit this process without selecting a new MIDI channel number
press the Multi Stomp at any time to exit. Please refer to the last 2 pages of this manual for MIDI
implementation but all the digital features of the pedal excluding the Resonance and Volume
controls which are analog are accessible by MIDI.
The Expression/ V System – The 1/4” jack on the right side of Dusk is where you can plug in an
expression pedal or a control voltage and have it take over for the Filter knob controlling the setting
of the filter. For expression you need to use a TRS cable the kind with 2 bands at the end. You can
use any resistance for this input anything from 10k to 500k will be fine. For control voltage you
need to use a regular TS cable the standard guitar/pedal patch cable with one band at the end. The
Dusk filter will respond to 0-5VDC signals.
The Preset System – Dusk has 4 internal presets for you to save your favourite sounds. The presets
remember digital things like the Mode filter setting LFO rate. They don't remember analog things
like the Resonance or Volume. You save a preset by holding the Left Pushbutton. You load a preset by
holding the Byp Stomp. When loading a preset it will load the next preset each time you hold the
Byp Stomp cycling back to preset 1 after preset 4. Each preset will light up a different colour on the
left side.
Thanks again! We really appreciate your support and we hope you enjoy Dusk!
-Dr. Scientist (Ryan & Tanya larke, Neil Graham)

Dusk Multi Mode Low Pass Filter
MIDI Implementation
# Function Value
9Remote Tap Any
20 Waveform Select 1 - 6 (0 becomes 1 >6 becomes 6)
23 LFO Rate x 1 (in BPM) 0 - 127
24 LFO Rate x 2 (in BPM) 0 - 127 (x2)
25 LFO Rate x 3 (in BPM) 0 - 127 (x3)
27 Waveform ++ Any
28 Waveform -- Any
29 Mode 1 - 3 1 - 3(0 becomes 1 >3 becomes 3)
30 LFO Subdivisions 1 – Whole Note
2 – Dotted Half Note
3 – Half Note
4 – Dotted Quarter Note
5 – Quarter Note Triplet
6 – Quarter Note (Default)
7 – Dotted Eighth Note
8 – Eighth Note Triplet
9 – Eighth Note
10 – Dotted Sixteenth Note
11 – Sixteenth Note Triplet
12 – Sixteenth Note
55 Save Settings to Preset 1 - 99
80 Bypass Foot Switch 0 - 63 Off 64 - 127 On
82 Left Stomp Hold (0 - 63 Off 64 - 127 On)
83 Freeze LFO (0 – 63 Pause 64 – 127
Resume)
102 Filter Knob 0 - 127
103 Ramping Speed 1 – 20 (0 becomes 1 >20 becomes
20)
105 Mode ++ Any
106 Mode -- Any
107 Envelope Direction 0 – 63 Down 64 – 127 Up

P # 0 = Bypass
P # 1 – 4 = Internal Preset # 1 – 4
P # 5 – 99 = Presets saved with MIDI #55
MIDI lock ontrols LFO Rate
MIDI hannel Reference Table
Mode LED Waveform LED MIDI Channel
Off Red 1
Off Green 2
Off Blue 3
Off White 4
Red Red 5
Red Green 6
Red Blue 7
Red White 8
Green Red 9
Green Green 10
Green Blue 11
Green White 12
Blue Red 13
Blue Green 14
Blue Blue 15
Blue White 16
White White Omni