How to build a DIY 3X VCO module from scratch

this is shapes a triple vco module that i designed and built from scratch it houses three independent analog oscillators that provide two switchable wave shapes each sawtooth and pulse with variable width the third one even has the ability to seamlessly blend between the two and of course all oscillators conform to the volt per octave standard so they play nice with most sequences that put out a cv signal [Music] in this video i'll walk you through the practical building process translating the schematic into a strip board layout designing and making a panel soldering everything together and then assembling it to get the finished product i won't delve into the inner workings of my circuit here because i've already done this in a four part series that you can find on my channel so if you're curious about the theory check those videos out and if you're not this should still be useful if you want to build your own module we'll start out with the schematic for a single vco you can find this along with all other sheets i use here available for download on my patreon now while this might seem like a huge mess of components at first you'll quickly notice that there's mainly two ics that everything revolves around a 40 106 hex schmidt trigger inverter and a tl074 quad op amp here's the two inverters and there's the three op-amps that we're using so if we were to build just a single vco we'd be wasting four perfectly usable inverters and one op amp because that be a shame and a single oscillator is not all too exciting i decided to step it up and go triple instead now if you don't care for the variable pulse width and would be cool with a fixed fifty percent square wave you could even get six individual oscillators out of one 4106 ic but since i like to have the flexibility and i don't want my panel to become too huge i'm sticking to my original design there's one slight alteration that i've implemented though in my original design i've drawn individual outputs for each waveform while i'm sure there's some uses for that i haven't really found any yet so to save some space i decided to have a single output per oscillator that can be switched and while i was thinking about this i realized that i still had some op-amps left so i came up with a way to blend between the two waveforms and added that as a special goodie for the third vco if you want to know more about how that works again there will be an in-depth explanation on my patreon soon with that out of the way let's talk about panels if you're trying to design a panel i've found it to be most helpful to first draw up a life-size template of the format you've chosen in my case i'm using a big non-eurorack format that sam over at look mom no computer popularized the reason being that i don't really like small audio jacks and prefer my synth to look kind of bulky and imposing so the base dimensions for my blank panel are 10 by 20 centimeters the first thing i usually do is mark the space that will be blocked by my case's rails just to be sure that i don't place any components there next i'll divide the panel into four columns one for each vco plus an extra strip where the labels will go then we'll have to decide on a layout for the control elements and connectors there's six per vco a coarse tuning pot a fine tuning pot a waveform selector a pulse width pods a cv input and an output socket and yes i am omitting the fm inputs from the schematic to be sure i get the dimensions right i'm tying around with the actual components if you try this yourself remember to not cram the components too close together might be difficult to assemble otherwise this setup works for me so i draw rough outlines where the actual components will go also i'm adding the exact positions for where we will need to drill later and that's all there is to the component layout for a panel though we'll have to come back to this once we know where the mounting holes for our circuit board are going to go to figure that out let's take our schematic and translate it into something buildable for that there's a bunch of roads you could take you could design a pcb layout and have it produced by a pcb prototype service you could use regular perfboard which is basically a blank pcb where you create the connections between components yourself or and this is what i like to do you could use strip board strip board has these strips of copper on the back that each connect an entire row of holes together this way all leads soldered to the same row are making contact no need to connect them manually like with the perf board on the other hand you'll have to frequently break the copper strips to prevent contact between components that shouldn't connect to each other but for me that feels a lot less tedious before we can get to soldering we should really draw up a layout on paper first if you're doing a really simple project with just a handful of components this might not be necessary but in our case just trying to wing it will definitely lead to a lot of frustration even if you're just doing a single vco there's just too much that could go wrong and then unnoticed now for layout drawing purposes i prefer using this dotted type of paper i like to imagine that every dot represents one hole on the strip board and each row is connected horizontally like this then i'll try to arrange the components as to replicate the connections shown on the schematic i won't lie to you this takes a bunch of attempts and some patience here's all the fake versions i've already discarded so the run i'm about to do will be far from my first try [Music] now that that's done it's time to double and triple check with the schematic just to be really sure that there's no mistakes and then we're good to start transferring this onto an actual piece of stripboard the first thing i always do is draw the power supply lines because we're not using the full-sized board i also draw the final dimensions and then cut the board with a standard box cutter next i first place and then solder the chip sockets because you can't really bend their legs and make them stay in place like you can with most other components then i place all the remaining [Music] components there's a small catch concerning the transistors and thermistors to make the vcos as independent of ambient temperature as possible i use thermal adhesive tape to bond them together time to solder all those legs down this is kind of messy because i do all of the components at once you could of course also do them in smaller batches but i got used to doing it this way and i think it might be a little faster finally i mark these spots where we'll need to cut the copper later plus where the panel connections will go it's important to cut the copper strips as short as possible because otherwise they might start acting as antennas and pick up signals from around the circuit to cut the copper i use a small drill bit the process is a little finicky because there might be very slim traces of copper left that you have to check for and cut as well finally we'll have to decide where we'll put the mounting holes and then drill them carefully to be safe i cut the copper next to the mounting holes too because the screws are making contact with the panel which will be grounded now that we have the mounting hole placement for the circuit board we can decide where we will drill their counterparts on the panel this is mainly a spacing issue because the sleeves i use to mount the board to the panel need to fit between the potentiometers and other components with the layout done we can now get to building the actual panel for that i first tape our layout directly onto the blank panel so that i know exactly where to drill for drilling the holes i'm using a run-of-the-mill power drill with bits made for metal specifically if you want your holes to be consistent in the exact placement i'd recommend drilling pilot holes first using a very small drill bit onto the actual holes their sizes vary depending on the components for the mounting holes i'm using a four millimeter bit the switches get six millimeter the potentiometers need eight millimeter holes and for the jack sockets we'll need the biggest holes at 10 millimeters with all the holes done i now send the aluminum down to smooth the edges and prepared for the lacquer to get the labels onto the panel i've found a technique that in my opinion looks quite nice first i draw up the logo plus labels and other flair on paper and cut them out using a precision knife next i glue them to the panel in the spots i want them to appear later i initially planned to have a master cv input here but i couldn't get it to work properly so i'll have to work on that some other [Music] time then i apply a few coats of black spray paint and let it dry once it is dried i remove the paper and here's how it looks after some cleanup to protect everything and make it look a bit more consistent i apply a few coats of clear lacquer on top almost done now we need to mount all the control elements to the panel there's another small catch here some potentiometers have these tiny protrusions next to the knob axis ideally you would also drill small holes for these but i found that the potentiometers have a good enough grip on the panel without them so i usually just cut them with pliers once that's done mounting all these components should be pretty much self-explanatory [Music] there's a few resistors that i didn't put on the board and that's why i'm now soldering them directly to these potentiometers from there i'm using a whole bunch of wires to connect the board to the panel then i add the power connector i use these simple three pin connectors that you can find very easily and for cheap [Music] and finally i'm mounting the circuit board onto the panel using two spacer sleeves and with that our module is done but before i put it in my modular let's make sure that it actually works so i'll connect my bench power supply and check if all three oscillators show signs of life luckily they all do so now i'll make room in my case and then install the module if you're interested in how the tuning process works again check the other videos in this series because i went into it in detail there i'm going to leave it out here and that's it for this video i'll leave you with a quick jam session to demonstrate how the module sounds in action if you've enjoyed this content and would like to see more of it in the future consider supporting me on patreon anyways thanks for watching and i'll see you in the next one [Music] [Applause] [Music] [Music] [Applause] [Music] you

Channel: Moritz Klein

Views: 42,084

Rating: 4.9853711 out of 5

Keywords: VCO, Synth, DIY

Id: OCAb2UoSPs0

Length: 16min 17sec (977 seconds)

Published: Mon Sep 28 2020

Reddit Comments

[u/dangerous_dickhead]

hi all,

here’s the final episode in my DIY VCO series. this one’s less about the „why“ and more about the „how“ – how do you take a schematic and translate it into a stripboard layout? how do you design a panel? and how do you then build the whole thing?

if you haven’t watched the other episodes, this could be a good starting point: you’ll get to see what the end result might look and sound like.

on a different note, i‘ll be hosting an in-person workshop here in berlin on the 11th of october. because of covid-regulations, we’ll have only a very limited number of tickets available. if you‘re interested, check out the event‘s facebook page: https://www.facebook.com/events/2605854579679702

thanks for watching!

[u/AirborneArie]

Do you plan on writing something up about this, with schematics and shit? It's much easier to digest than scroll back and forth through a video.

[u/HeegeMcGee]

VCO: nice

1/v octave: Okay, juicy!

stripboard: i'm aroused, don't stop

[u/sandelinos]

Holy shit they made 3xosc into a real thing :O /s

[u/RaidersRhett]

Your content is always great. Thanks for the upload!