Marsupial Eurorack User manual

Marsupial Dual Voltage-Controlled Filter Eurorack Assembly Instructions
Copyright 2021 SetonixSynth. All rights reserved.

Hello and thank you for using the Marsupial Dual Voltage-Controlled Filter Eurorack DIY
kit. We hope you will find its tones most pleasing!
Kit Contents:
1x Panel and Pre-soldered PCB set
10x Thonkiconn 3.5mm jacks with knurled nuts (J1-8, J10, J11)
3x B10k 9mm potentiometers (RV1, RV2, RV3) with washer, nut, and 6.35mm adapter sleeve
2x Plastic shaft B100k potentiometers (RV4, RV5)
2x Davies 1900h knobs
1x Davies 1910CS knob
2x 3mm red LED (LED1, LED2)
2x 25k multi-turn trimpot (RCV1, RCV3)
1x SPDT On/On sub-miniature switch (SW1)
1x 2x5-pin Power Header (or 2x 1x5 headers)
1x 1x3-pin Header
1x 2.54mm Plastic Shunt
1x 10-pin Eurorack Power Cable

Assembly Instructions:
1. Delicately unpack your kit. Try not to touch the pre-soldered circuit-board with your bare hands if
possible. Make sure that all parts listed on the previous page are present in your kit. If they are not,
please contact us at [email protected] and we will arrange replacements for you.
2. Prep your components: use an edgecutter to remove the anti-rotation tags on the three metal
potentiometers and put one nut on the SPDT on-off switch. Though not shown in the picture below, it’s a
good idea to put the washers on the three metal potentiometers before mounting the panel.
3. Solder the rear through-hole components: the 2x5-pin power header, 3-pin Series selection header,
and two 25k multiturn trimmers should be soldered in the manner shown above, on the same side of the
PCB as the surface mount parts. Note the orientation of the two trimmers, with Pin 1 towards the right
when looking at the PCB from the rear. Don’t forget to place the plastic shunt over two of the three pins
of the 3-pin header--”BP” will normalize Filter A’s Bandpass output to the Series switch, while “LP” will
normalize Filter A’s Lowpass output to the same. We recommend the “LP” setting but either is good.

Frontal components, unsoldered
4. Place all frontal hardware in the appropriate place on the circuit board but do not solder any of these
parts yet: the three metal potentiometers are RV1, RV2, and RV3, while the two plastic ones are RV4
and RV5. Also place the Thonkiconn jacks, Subminiature switch and two red LEDs (cathode aka short leg
corresponds to the square pad of each footprint).
5. Place the Marsupial panel over all mounting hardware. It might take a little finesse to fit all components
through their corresponding holes, but be careful not to unseat any of the hardware as you place the
panel.
6. Keeping the panel as close to the PCB as possible so as to make a tight “sandwich” of components,
fasten all hardware (nuts for Thonkiconns, B10k potentiometers and Subminiature switch) and tighten
them with your fingers as much as possible to pull the hardware snug to the panel. Make sure not to pull
anything out of the PCB while doing this!
5. While ensuring the sandwich is maintained, flip the module upside down (PCB facing up) and double
check that all hardware is properly seated in the appropriate PCB holes. If you have a bench vice of some
kind, this is a good time to use it!
6. Push the red LEDs into the appropriate front panel holes so that they sit as far forward as possible.
Solder one leg of each LED and double-check their position before soldering the other leg and trimming
with an edgecutter.

7. Solder the other frontal hardware except for the plastic B100k pots. We recommend starting with the
Thonkiconn jacks or 9mm B10k potentiometers, making sure the nuts on each continue to hold them snug
to the panel while still staying attached to the PCB. Hand-tightening the nuts should help with this.
8. Once all other hardware is soldered in place, solder the plastic B100k pots. These can be a little finicky,
so push them into the PCB so they sit squarely and solder one of the side legs first. Before soldering any
more, flip the module over and double-check that the shaft of the pots aren’t touching their panel holes. If
the pot is off-center, reheat the one pad and adjust the potentiometer until it sits squarely. This might take
a few attempts and caution should be exercised not to destroy the pot by overheating. Once the pot is
positioned correctly, solder the rest of the pins and the other leg in place.
6. Double check your work. Make sure all components have properly flowed and that all hardware is
properly soldered to the PCB. We will have inspected the PCB in-house, but mistakes can sometimes
happen so feel free to contact us if anything looks incorrect. If everything looks good…
7. Plug in your Marsupial! Make sure the red stripe on your ribbon cable corresponds to the stripe on the
PCB which indicates the -12V pins. Test all functions: even without calibration, you should be able to get
nice filter sounds from all four outputs, test all CV inputs, and adjust the Resonance from zero to
self-oscillation. If everything seems to be working properly, it’s time to calibrate the module.
Calibration Procedure:
1. Power on the Marsupial and leave it powered for at least 10 minutes. Set the switch to “Parallel” mode,
move “B Offset” knob to 12 O’Clock, and set Resonance knob to full CW so that each filter self-oscillates.
2. Connect a 1V/Oct source to the “1V/Oct A” input. As this is a filter and tracking is likely not critical,
home studio staples such as the Keystep, MI CVPal or MFOS V/Oct Calibrator may suffice depending on
your desired level of precision.
3. Monitor the “LP A” audio output with a tuner or frequency counter. Set the pitch of Filter A to a
mathematically simple frequency such as 110 Hz and use the rear “A-Tune” trimmer to tune Filter A so
that its frequency is roughly 880 Hz with 3V applied. This should provide a good ballpark starting point;
from there monitor the frequency at other 1V intervals up to +5V and adjust the trimmer so the output
frequency is as close to the corresponding multiples of the initial frequency as possible.
4. Once Filter A has been tuned satisfactorily, monitor the “LP B” output instead, making sure nothing is
patched to the “1V/Oct B” input. (This will normalize the incoming CV signal to the 1V/Octave input of
Filter B.) Repeat the procedure from Step 3 for Filter B.
5. Enjoy your filter!