PARASIT STUDIO Multiwave Mega User manual

Multiwave Mega
Guitar Synthesizer
Build Document last updated october 2019
Version 1.0 2019
The Multiwave Mega is a monophonic wavetable-based guitar synth with
an analog resonant lowpass filter. t has two oscillators with several
waveshapes that can be blended together and detuned, guitar triggered
filter envelopes, a sustain mode (aka ”drone mode”) and an LFO with
several waveshapes for modulating both amplitude and frequency.
Happy building and playing!
Note: When first powering up the pedal, the sustain function may be active, so to first get any
sound through the pedal, make sure that the sustain is off (by pressing the sustain
footswitch).

Controls
For more details on the Mega features, please download the user manual
from: www.parasitstudio.se/mega
BUTTON FUNT ONS
The four push buttons has three different functions each:
•Normal press
•Long press (press and hold for at least 500ms)
•SH FT press
The top row describes the normal push functions.
The second row describes the long press functions.
The bottom row (below the buttons) describe the shift press functions.
When doing a long press, the ED will blink twice and when doing a shift press it will
blink three times fast, to give a visual indication of the button response.

BUTTON 1
WAVESHAPE - toggles through the waveshapes for the primary oscillator.
SELECT - selects the current waveshape for the secondary oscillator.
SH FT - Press and hold, then push one of the other buttons to activate their
respective shift functions.
BUTTON 2
DETUNE - toggles through 6 different detune setting for the primary oscillator.
BLEND - activates the secondary oscillator, blended with the primary oscillator.
OCTAVE - makes the secondary oscillator go one octave down.
BUTTON 3
ENVELOPE - toggles through 3 different envelope shapes (when the VCF is on).
VCF - turns the VCF on/off - the guitar triggered filter cutoff envelope. *
LFO - makes the filter envelope an LFO insted of being triggered by the guitar.
* Note that the threshold control needs to be set for the envelope to trigger
BUTTON 4
LFO SHAPE – toggles through the LFO waveshape (when the LFO is on).
LFO on/off – turns the LFO on/off.
MODE – switches to a different LFO mode for a different kind of modulation.
THE SUSTA N FOOTSW TCH
The sustain footswitch will activate the sustain mode. t has two different sustain
modes, either 1. - a manually enabled hold, or 2. - a guitar triggered hold, depending
on the SW MODE switch position.
The SW MODE switch
Down position - Manual hold mode. Press the sustain footswitch to hold the note.
Press it again to go back to normal operation.
Up position - Guitar triggered sustain*. Press the sustain footswitch to enable this
mode. Press it again to go back to normal operation.
* Note that the threshold control needs to be set for the sustain to trigger.
POTENT OMETERS
LEVEL – controls the overall output volume.
RESO – controls the amount of filter resonance.
CUTOFF / RATE - controls the filter cutoff.*
RATE – controls the speed of the LFO.
THRESHOLD – sets the trigger point for the sustain and envelope. For the best trigg
result, you may also try adjusting the input sens trimmer on the PCB.
* in VCF mode, this pot will control the rate of the filter envelope and filter FO.

General builds tips
•Solder the low profile components first, from short to tall height. Recommended
order: resistors, diodes, C socket, film-caps, electrolytics, pots and switches.
•CMOS chips are very sensitive to static charges and can be easily damaged. t's
a good idea to wear a anti-static wristband.
•Always use sockets for C chips and transistors to avoid heating them directly.
t also makes it much easier to swap them out if needed.
•Pay special attention to the orientation of the diodes, electrolytic capacitors,
LED's and the voltage regulator.
•This PCB's is designed for 16mm Alpha PCB mounted angeled pots, except for
the threshold pot which needs to be a 9mm PCB mounted type.
•Cut off the outside mounting pins on the 9mm threshold pot, so that it fits
against the PCB (do not cut the 3 middle pins!)
•Mount the pots and the switches to the back side (solder side) of the PCB and
solder them from the front side (component side).
•Cover the back of the pots (with pot covers or tape or a piece of carbon) so that
they don't create a short on the PCB.
•Cut off the small tap on the potentiometers, so they can sit flush against the
PCB.
•When mounting the PCB in the enclosure, recommend that you take the
following steps:
1. Place the SPDT switch and buttons inside the enclosure.
2. Place the potentiometers on your PCB.
3. Solder only the middle pin of each pot to keep them attached but allowing
some movement.
4. Place the LED's in the PCB holes without soldering.
5. Carefully place the PCB inside the enclosure, make sure everything lines up.
6. Solder everything in place.
If you are having trouble getting everything lined up, try mounting and
soldering one type of component at the time. For example, start with the pots
and place them on the PCB, carefully place the PCB inside the enclosure, then
solder. Then remove the PCB from the enclosure do the same method for the
switches/buttons, then do the ED's ect. Takes alittle bit of extra time having to
add and remove the PCB from the enclosure a few times, but makes it much
easier to get everything lined up.
tech notes
Current draw: 45mA
(measured without the O ED/Attiny85)
This pedal draws alot of current, so keep this in mind when powering the pedal,
especially if you are using a pedalboard with many pedals. I don't recommend using a
battery with this build since it will drain pretty quickly.

Multiwave Mega Bill Of Materials BOM)
•The PCB from Parasit Studio and the D Y kit from Musikding comes with a
pre-programmed Attiny84 chip.
•The push buttons are momentary normally open (SPST-no).
I use these: https://www.taydaelectronics.com/electromechanical/switches-
key-pad/push-button/white-knob-push-button-panel-mount-spst-no-pb-11d02-
th1-00.html
Resistors R32 100K IC's
R1 10K R33 100K U1 CD4069UBE
R2 47K R34 10K U2 CD4046BE
R3 470R Capacitors U3 CD4040BE
R4 22K C1 100nF U4 ATT NY84(*)
R5 22K C2 100nF U5 CD4066BE
R6 22K C3 1nF U6 TL974***
R7 10K C4 4.7nF U7 ATT NY85(*)
R8 100K C5 100pF (*) pre-programmed
R9 22K C6 220nF*
R10 15K C7 22pF Potentiometers
R11 10K C8 22pF LEVEL B100K
R12 330K C9 150nF RESO A10K
R13 10K C10 1.5nF CUTOFF C10K
R14 1M C11 4.7nF RATE C10K
R15 1M C12 100nF THRESHOLD(*) B100K
R16 1M C13 1nF
R17 1M C14 100nF (*) 9mm pot
R18 10K C15 1uF*
R19 15K C16 4.7nF Buttons & switches
R20 39K C17 10uF 4x momentary push buttons
R21 470K C18 10uF 1x SPDT on/on (SW MODE)
R22 15K C19 100nF* 1x momentary SPST footswitch
R23 10K C20 10uF (sustain)
R24 1M C21 1uF* 1x 3PDT footswitch (bypass)
R25 10K C22 100nF*
R26 4.7K Diodes misc parts
R27 4.7K D1 1N4001 1x 20mhz crystal (Y)
R28 10K D2 1N4148 1x 78L05 voltage regulator
R29 CLR** D3 1N4148 1x 200K trimpot (input sens)
R30 CLR** D4 1N5817 3x LED's
R31 CLR** D5 1N5817 1x 128x64 4-pin SP OLED

•* Use multilayer ceramic capacitors for these values – important!
•** Current Limiting Resistors for the LEDs'. Use the appropriate value for your
LED type. recommend using 4.7K resistors for diffused LED's or 15K resistors
if using clear superbright LED's.
Note that these ED's are powered from the 5 volt rail, so the resistor value can
be a bit smaller than what you usually use with a 9 volt supply, but avoid using
anything less than 4.7K to limit the current draw from the voltage regulator.
•The top LED is used as the bypass indicator (aswell as a push button indicator)
so you don't need an extra LED for the 3PDT.
•*** You can also use a common TL074 if you don't have a TL974, but really
recommend using a TL974 since it will be much less noisy with a higher
headroom for the filter (it can distort, and not in the good way, when having the
resonance maxed).
•The PCB is designed for angeled PCB mounted 16mm Alpha pots, except the
threshold control which needs a 9mm PCB mounted pot.
Cut off the outside mounting pins on the 9mm threshold pot, so that it fits
against the PCB (don't cut the 3 middle pins!).
•The 200K trimpot sets the input sensitivity.
Adjust the sens trimpot from very noisy when barely touching the strings to
very gated. Find a good balance without making it too gated (it will cause the
trigg/threshold much harder to adjust).
•The components that are greyed out (inside the outlined area on the PCB) are
only used for the OLED oscilloscope circuitry. t is are not included or supported
by the PCB or D Y kit, and only used for the fully assembled Parasit Studio build
(which shares the same PCB layout for my own convenience). Sorry to
disappoint anyone!
The reason that it's not included is because it would make the build much more
difficult. Alot of people does not have the tools needed to make a square hole in the
enclosure. It also adds a big extra cost. The oscilloscope is a fun novelty feature but
not really necessary. :)
That said... if you really want to add it, you can find the HEX code for the Attiny85
(that is driving the oled screen) in the blog, but you have to program the chip
yourself. Parasit Studio is not selling preprogrammed Attiny85 chips for this use, with
no exceptions.
Other things needed that is not included in the BOM:
•enclosure - 1590BB (or bigger)
•input & output jacks
•DC jack
•led bezels
•knobs

Offboard wiring
•Note that the DC jack only needs to be connected to the pads at the top of the
PCB.
•t's not necessary to connect the 9v pads between the PCB and 3PDT board.
The picture shows this connected, but it's not really needed. I personally use
ribbon cable between the boards and then it's easier (and looks more tidy) to
just include the 9v connection aswell.
•You can ignore the four pads on the left side of the PCB next to U3
(marked x2, x8, x4, U). These are not used.
•I don't recommend using a battery with this build, because of the high current
draw (45mA). The battery would drain pretty quickly.

Drilling template (1590BB)
•This template is approximate. Use at your own risk!
•Make sure your printer isn't doing any scaling / is set to 100% print size.
•The PCB have a top cutout for the DC jack, to have the DC jack mounted in the
middle of the top side of the enclosure.
•Drill the input/output jacks to your own preference between the PCB and the
footswitches. I recommend using Lumberg type jacks, which are smaller
than normal open jacks and will allow for more drilling errors, since
this is a tight fit...
Measure and confirm before drilling!
Hole sizes
◦Potentiometers and push buttons 7mm (0.2756 inch)
◦LED's (for 3mm LED's with LED bezels) 6mm (0.3462 inch)
◦SPDT switch 6mm (0.3462 inch)
◦3PDT (bypass) and sustain footswitch 12mm (0.4724 inch)
(DC jack, input and output jacks holes can vary depending on type)

Schematic
Please note that DC filtering, polarity protection, voltage regulation, Vref and the O ED display
associated circuit is not shown in this schematic

Troubleshooting
There's always a chance of running into trouble. To minimize error, follow the
BOM and general building tips carefully. Take your time and don't rush. Take a
break now and then. Use good solder, and it helps to have a decent soldering
station insted of a cheap iron.
f you are still having trouble, please visit the madbean forum Parasit Studio
subforum section and ask for help there.
http://www.madbeanpedals.com/forum/index.php?board=84.0
f you have bought the Musikding kit and have recieved a faulty or missing
component, please contact musikding directly.
https://www.musikding.de/kontakt.php?lang=eng
Terms of use
PCB's from Parasit Studio are intended for D Y use only. Commersial resale is
not allowed. t's meant for personal use only, which means that it's not allowed
to build alot of pedals and sell them for profit to strangers using public forums
and craiglist ads ect. However, it's totally ok to build a few pedals and give to
your friends and bandmates. After all, that's what this hobby is about. :)
www.parasitstudio.se
[email protected]