CubuSynth 4VCLFO Quad Voltage Controlled Triangle LFO User Guide
- June 9, 2024
- CubuSynth
Table of Contents
SMD PCB V1.2 Dec2022
4VCLFO
Quad voltage controlled Triangle LFO
Build Guide
SMD PCB V1.2 Dec2022
Written and Illustrated by Ruben Sponar
CubuSynth 4VCLFO- Build Guide 
Introduction
The 4VCLFO is four LFOs with triangle Outputs in 10hp. It features a knob for
the Frequency of each LFO and CV inputs with attenuators.
The „Aux“ input is normalized to the four CV inputs, so you can modulate all
LFOs with one signal at the same time. Plugging a cable into the CV input
breaks its connection from the aux input.
This way you can create more interesting Modulations for your Patches.
Tools Required
Soldering iron (+wire) side-cutter
Nut wrench / driver M8 – optional:
Digital Multimeter
Helping (third) hand / PCB holder
BUILD GUIDE
STEP 1 LEDs
Place the LEDs like shown below.
Orientation of the LEDs is Important. The longer leg of the LED goes in the
squared hole.
Make sure to have the colors placed as below to correctly indicate the LFOs
Polarity.
One of each color represents positive or negative Output voltage for each LFO.
In this case green stands for positive and blue for negative voltages.
STEP 2 Power Header
Place the Pin Header for Power like shown here.
Orientation of the Power Header is very important to be able to insert the
power cable the correct way.
Put some tape, to hold it in place while soldering from the other side.
You can also solder only one pin, while holding the Power header in place.
Then solder the remaining Pins.
STEP 3 Electrolytic capacitors
Place the capacitors on the PCB with the white line of the capacitor facing
down towards the white mark on the PCB. The longer leg of the capacitor goes
through the hole marked with “+” You can bend the solder legs outwards, like
shown below, to keep them from falling out.
Then solder and cut the legs.
You can easily customize the LFO speeds to your taste. Choosing larger
capacitors will make the LFO slower. You can also choose a different value for
each of the four LFOs.
Here is some capacitor values with LFO times / frequency ranges:
| cap. Value | seconds | frequency (hz) |
|---|---|---|
| 10uf: | 140~5 sec | 0.007~0.2 hz |
| 4.7uf: | 70~2.5 sec | 0.014~0.4 hz |
| 1uf: | 14~0.5 sec | 0.07~2 hz |
| 0.1uf: | 0.5~0.014 sec | 2~70 hz |
LFO 1 – capacitor C12
LFO 2 – capacitor C13
LFO 3 – capacitor C14
LFO 4 – capacitor C15
STEP 4 Controls
Now take the Potentiometers and jacks and put them in place as marked on
the PCB but don’t solder yet.
In the picture you can see the placement.
When everything is in place, take the front panel and put it on top, so all
controls go into each corresponding hole of the panel. “wiggle” the front
panel into place and make sure everything fits well.
Fit all nuts to the Potentiometers and the Jacks.
Be careful when turning the boards around, so that all the components stay in
place.
Then solder everything.
STEP 4 final check
Check your soldering. If you see shorts or bad solder joints, fix it up.
Then check the power pins for shorts with your multimeter. If everything looks
fine, you can place the knobs, so the pointer is correctly orientated and push
them down.
Now you can install the module in your rack and have fun patching!
Help
Please understand that we can’t guarantee for your DIY module to work.
Nevertheless we will do our best to guide you through the build or to solve
problems when needed.
In case there should be parts missing in your Full DIY kits contact us to ask
for replacement / If you have trouble with your build, you can contact us at:
cubusynth@gmail.com
To be able to identify mistakes in your build, please include high quality
pictures of your soldered PCBs, front+back.
https://cubusynth.com/
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https://www.instagram.com/cubusynth_modular/
https://www.etsy.com/shop/CubuSynth
References
- Cubusynth- Eurorack Modular Synths & Diy Kits – CubuSynth
- CubuSynth - Etsy
- CubuSynth (@cubusynth_modular) • Instagram photos and videos
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