How to build a DIY 3X VCO module from scratch

Support the channel: / moritzklein
In this series, I'm taking a detailed look at how to build an analog VCO from scratch, using just a handful of cheap components. It's the basis for any synthesizer. To keep it as beginner-friendly as possible, I'm explaining everything step-by-step & at length.
In this final episode, we're putting all the theoretical knowledge we've gained in the past 4 episodes to work and build a proper triple VCO module.
Chapters:
00:00 Intro
01:41 Schematic analysis
02:54 Wave mixing
03:35 Panel layout design
05:24 Circuit board options
06:19 Stripboard layout design
08:00 Building the circuit board
09:59 Building the panel
12:32 Adding control elements/connectors
13:11 Connecting panel and board
13:50 Testing and mounting
14:30 Outro and sound demo

[@theVHSvlog]

Hey Moritz, I really wish your channel existed in 2010 when I was just learning about synths and attempting to build my own. You've honestly given the community a huge gift with these tutorials. Thank you

[@vincentfree1889]

This channel is such a gem, absolutely love every video you put out. Would also love to see some more jam content, that setup looks amazing!

[@MoritzKlein0]

Vincent Free i‘ll see if i can come up with something worthwhile!

[@svg98]

What a ride, loved every second of it!

[@Jack-hy3ye]

Great work mate, this channel is incredible. Quickly becoming one of my favourites!

[@spartang0]

great content, great editing and great sound. thanks for making this video

[@oscarmoralesjuarez2274]

This channel is just insane. Congrats for this sublime content.

[@dcsapporo]

Moritz, thanks for your great videos.

[@watchclark6482]

Love it, nice work!

[@lucashenry2556]

Thank you so much for this content! I've been building a modular based on Sam's designs, but having a more in depth discussion of the circuitry is SO important to me. I plan on building this as my next project. Keep up the great work!

[@alexandrefails2312]

I am starting to learn more about synths. Your channel is just nothing short of incredible

[@DiaconescuAlexandru2024]

05:38 you can also make your own PCB's, although you will have to handle ferric chloride (which as long as you wash your hands and don't start sniffing the fumes will be more of a danger to your iron tools than to you). You just need a plain copper board and a permanent marker/corrector paste to draw the tracks on it. Before drawing the tracks I recommend drilling the holes for the components first and then connecting the holes with corrector paste while having some cardboard under the copper board. After the track drawing is done you need to put the board in ferric chloride and move it around (you can drill a hole in the board and put some wire trough it) every 20-30 minutes until you see that all the exposed copper was corroded. Then you get the board out, wash it under warm water with a steel sponge and then pour back all the ferric chloride back into it's bottle. Everything that has touched the ferric chloride HAS to be washed. Also, I usually recommend perf boards when you don't need to care about stray capacitance and inductance, so I use DIY PCB's for RF stuff, signal generators I really care about and high power stuff, it's a waste of my time to make a PCB for every little circuit with some LED's and transistors.

[@CircularMirror7]

Holy hell that's a good idea. That way you use too design a panel will help me greatly. No more screwing up placement.

[@fakenamerealguy7084]

I am gonna build this. Thank you for this channel, the quality is really top notch (or at least is exactly how I like it) ! I hope your sub count explodes (or your Patreon{or both!}), but until then I wanna convey my appreciation. It's nice to share the world with folks like you!

[@martylawrence688]

When you started doing your layout on the dotted paper (7:18) I got shivers... something about tech stuff laid out this neatly makes me inordinately happy. AWESOME work Moritz, really informative and entertaining, I've subscribed and can't wait to see what you make next!

[@wesleymays1931]

My schematics, at best, are electro-lasagna

[@michaelliuzzi]

Just subbed to your patron. Just give you a huge thanks. I learn best in a project oriented fashion and your explanations and process are extremely lucid. Thank you.

[@simmelj]

This is soooo cool! Thanks for these informative and easy to follow videos. I know what my winter project is going to be! :D

[@mattbutler5095]

Dude you are an absolute genius, watching you do the strip board layout , I was amazed, I wish I had that ability, great work dude best of luck for the future dude 👍👍👍👍👍👍

[@finonomastropiero4261]

Best diy modular Channel

[@shaiant5316]

Love your stuff❤

[@ewencousin]

keep doing it, its so great!

[@akasickform]

I wish this channel existed years ago, as it's now helping me to further realise myself and progress, also reaffirming existing knowledge. Thank you for providing.

[@arsenicjones9125]

I’m late to the party but I find a step bit is much easier for drilling holes after the pilot hole is drilled. Also I don’t cut the retainer on the pot anymore, if you grip it w some pliers and torque it sideways it’ll snap off clean every time w no risk of tiny metal bits shooting off like sometimes happens when you cut them. Great work. Love the cosmo format! Big everything feels big

[@socks7545]

Oh I'm about this, and that shirt you're wearing during the demo is sick

[@HanjoSynth]

amazing channel! thanks for sharing

[@rafecamp]

love this channel

[@lucianomartinez2927]

What a big proyect!! excelente!! keep going hermano!!

[@junglimikejunglist191]

Thank you so much for the video!

[@UnauthorisedService]

Great content...and build ... ! 👏

[@coreyfridinger8242]

Absolutely brilliant!! Nice how you expanded the VCO from a single voice to three and the option of the variable VCO to blend the two waveshapes together. You should definitely get some interesting sounds. Simple, yet satisfying!! I will be following you during this entire project and am hoping for more insight on your modular rack. I have built a MIDI to CV unit (using a PIC) that adheres to the 1V per octave standard. Your insights on the control and operating aspects are really good. Looking forward to future videos!! Keep up the great work!!

[@MoritzKlein0]

thanks, much appreciated!

[@channelite]

Awesome! I am inspired!

[@pseudopseudo3679]

Your videos are really special :D

[@juansoto3469]

U are actually amazing bruv thank you

Respekt! Ich bewundere dieses Wissen und könnnen!

[@johnvcougar]

Dude! That's one very neat hand you have there.

[@skriptico]

Lovely stuff, the vero project would be really great!

[@ProductOfTV]

when you cut the small nibblets on the pots, instead of cuting you can break them off cleaner with normal pliers, they break right off and wont leave any pertrusions. Greetings :)

[@autoalejoangora6173]

thanks a lot Sr.!

[@TimSavage-drummer]

Love the series. For drilling panel holes, get yourself a step drill. They are a big timesaver not having to change bits between hole sizes and you can also give the holes a de-bur with the next step.

[@MoritzKlein0]

thanks for the tip, will look into it!

[@PWMaarten]

After drilling the pilot holes I recommend removing the paper. Paper will make your drills ga blunt faster.

[@nict2618]

That is awesome.

[@Gin-toki]

Really great content you have made and nice explanations of your thoughtprocess aswell as the circuits. Great for teaching beginners in making DIY synths :) A recommendation for drilling holes in thin sheet metal, use a step drill, it creates almost perfectly round holse and leaves littel to no burr on the edges, compared to a standard twist drill which makes traingular (tribolar) holse when drilling in thin sheet. It is also easier to center correctly, especially when making larger holes, since you start off with a small pilot hole.

[@MoritzKlein0]

will try that next time, thanks!

[@woosix7735]

I built it about a year ago now in Kosmo format, it's great!

[@FreddyBNL]

Impressive👍

[@firfen3782]

This was a fantastic build, only had one problem with the VCO so far and wanted to post the solution (just in case). If the VCO is inexplicably oscillating at a very low frequency no matter where the tuning pot is, disconnecting and reconnecting the negative power rail will fix it. For some reason if you disconnect power entirely it still oscillates too low upon a restart. I have no idea why this happens but there you go!

[@tupointgg3907]

thank you sosososoosso much❤

[@dooterino]

I'm a big fan of the Look Mum No Compu'ah method of panel design: paint it black and go nuts with a silver sharpie

[@MoritzKlein0]

same!

[@existential_fred]

Yeah I thought it was one of his tbh

[@christianverryckt1342]

Hey Im professionally versed with electronics and your descriptions go beyond tank and valve, r & c circuits water dynamics equivelents. Great analogy descriptions.. Divider and offset, tune are well described.

[@victorlucas9169]

Crazy shirt, got that jakin and bohas representation

[@vitaminscene]

THANKS

[@IG-88r]

you can bend the legs of the sockets using a piece of perfboard: you put them in place, align a second perfboard and then move it sideways, the legs will be slightly bent, just enough to hold while soldering but not enough to damage or break

[@wedkarzkosma]

maan i love every thing you've made

[@dunichtich100]

Junge du bist sowas von krass! 🤯💥

[@geoffreyhoffman2739]

Amazing

[@milosimon1519]

Awesome video man! I was wondering if I were to build something similar to the required dimensions of a eurorack module if it would be compatible with other eurorack modules. Thanks and keep up the great work!

[@MoritzKlein0]

yes it would! though you‘d have to use a proper eurorack power connector to hook it to your power supply.

[@obe726]

Diylayout for the pc is a life saver when designing for perf or strip board. Edit: drilling if you want to get the holes perfect. Use a center punch

[@mojibake7868]

Super video. This is something I'd love to be able to do. I'm an artist/programmer/musician by trade and I've always been 'scared' of building hardware. You should look into screen printing your design on the aluminum. It very cheap, much more accurate/tidy and can be done at home! The colour of screen prints can be fabulous as well compared to digital/laser/inkjet print. Plus, it instantly looks more professional :)

[@lumotroph]

Holy shit that is so cool.

[@floretionguru2977]

You know, those tiny protrusions on the potentiometers next to the knob axis have always annoyed me and I never thought of the obvious: just try to cut them off. Great little tip there!

[@DonErikos]

thanks !

[@jimmy_jamesjams_a_lot4171]

You’re great!! How long did it take you to go from playing around with schematics online and in books, to actually starting your way with actual designs, to where you are creating your own layouts and all the parts in schematic form? I mean, you are a terribly thorough person, and you seem to be quite cautious and careful with your progress. I have these fears of suffering fails that become costly, until eventually I spend too much time triple checking, and less time failing! Your theory is so strong, as well as your practice. And your work shows that it pays off infinitely, no!!? That crazy sequencer that’s stepping along in the end, the one with the wiggling LEDs, what module is that?! The one that’s on top row and about third or fourth one from the left? That’s really cool, how the lights move along in that one! I’m guessing it uses a shift register as a sort of memory for keeping track of drum patterns or something like that. Really cool, THANKS SO MUCH FOR SHARING!!

[@maxspencerkarinen6463]

These videos are amazing! its so inspiring to know (sort of haha, some of it is still sinking in) how all of the parts work and the theory behind it. Do you have a Bill Of Materials for this module?

[@josepharamide3640]

The mixing circuit is really really good, I just simulated it now on multisim, as expected at 50% position percentage of the potentiometer it blends to the two nicely together, but at 0% I see pure FM wave which stays 5 volts but whats interesting when its 100% its give me am which a few volts higher than my input of 5 volts.

[@jj74qformerlyjailbreak3]

Great stuff I just stripped a 50” Panasonic plasma tv. I removed the panels leaving me with a nice solid aluminum panel and solid box for a complete diy experience. Built solely from what god gives me. Right now I’m toying with a digital J11 16 bit processor simply because of its name. We have a few things in common. 😂

[@giliack7017]

Great!!!

[@indivisiblemomentum]

Hi! great video and series, thanks for sharing all that knowledge to the community. You mentioned that you had troubles making a master cv input, what kind of problems were those? I really want to make the oscillator have a master cv, and would like to know what I'm facing to.

[@MoritzKlein0]

nothing really difficult. for some reason i assumed a single buffer shared by all three VCOs would be sufficient, but that's not the case. you need one buffer for each vco.

[@cesarsuarez4491]

What a great channel! Looking forward to building this. Does the Patreon provide any detailed circuit analysis.

[@MoritzKlein0]

you mean a mathematical analysis?

[@daithibailey]

Great video, regarding the finish of the face plate: when finishing guitar pedals I find a good idea is to use a combination square to mark the drill points with a small cross, then you know all the knobs will be in line with each other. You can use a nail to punch a mark on the metal to give the drill bit something to bite into, otherwise it might wander off course. The best way I've found to finish enclosures is to draw up a design in photoshop and include a drill template. Then you can just print off the template and punch and drill knowing it'll fit in perfectly with the design. As for getting the design from photoshop onto the faceplate, I've had really good results with waterslide decal. It might look a bit labour intensive at first, but it's actually fairly easy once you get used to it and the results can look really professional.

[@MoritzKlein0]

i'll be sure to try that out! thanks!

[@zerstaerker]

Hey Moritz, thank you for this great SDIY video compendium. Nicely put together btw. When deriving more than one oscillator from a single 40106 chip, have you gotten around the issue of a weird sync or phase-lock if those two oscillators are tuned close to each other? I faced that problem when I built a dual VCO with single supply V/oct current sink a few years ago but don't know how to fix it. Have anice sunday. MfG. :)

[@TheNimasan]

grossartig....ebenso verständlich für einen laien wie mich. aboniert!!! neue fav kanal!!!

[@derfred9571]

das ist so cool

[@maruasg2574]

Hi Mortiz, I have a doubt. At what components did you connected the potentiometers?

[@andreasgross4799]

Hallo, danke für den guten bauplan. ich habe jedoch probleme beim stimmen. wen ich meine tune potis mittig habe und der sequenzer zwischen C4 und C5 mit meinem Tuner präzise gestimmt ist und ich dann die Potis nach auf drehe wird mein gemessener Octavenabstand kleiner, und wen ich sie nach unten drehe wird der gemessene abstand größer. Woran könnte das liegen? liegt es vll daran dass ich BC548A und BC558B verwendet habe und nicht die mit dem selben Buchstaben?

[@matthiasreichert4016]

very nice videos, i startet with pedals and then did some mini drone machine circuit bend stuff with the simple oscillator from lookmumnocomputer. now i want to built a bigger synth for drone and noise music. your video are very helfpul for the filter section and now im thinking about making it voltage controllable to add a baby 8 like sequencer. i was thinking about adding a stereo delay aswell. maybe you are interested in making a video about analog fx or fm synthesis in the future :D keep it up!

[@MoritzKlein0]

yes definitely! delay and reverb are on my list.

[@penalvalouis554]

Great work mate. Any chance to know where u get ur shirt or the brand ? Thx sir

[@94BR]

i am very sad that i didn't get MKI as a prof. Grande mki dall Italia 🇮🇹 💪🏻

[@timcampbell3735]

Great video! One question: what is the third potentiometer (first and second channel, or last on the third channel)? Is it the 1M pot from the FM IN path, or the 100K connected to the third op amp?

[@kiranscottdemartinville3304]

That shifts module looks really cool, could you explain what it does? ty and keep on making content :)

[@protozoid4571]

thanks so much for these videos. really great stuff. just wondering about the thermistors. cant you get away with just having one after those inputs are all summed together, instead of each having its own?

[@johnirving8237]

I was thinking the same thing because they are not cheap

[@straticah2865]

ok wow i am just blown away and it looks so complex for me but i would love to learn more! my music is very analog, so can u explain what makes a module analog or digital sounding? I would like to learn how to build modules with analog circuitry because i love the sound of my analog compressor and my tape machine. Greets Julien

[@ghosthardware__]

Hi, how is the wave mix potentiometer connected and what value it has? im sorry if it's completely basic question but im new to electronics and diy synth stuff

[@XtianApi]

As far as the labels I would look at anodizing because the way that came out you may as well just use a silver Sharpie marker and draw the lines

[@burgerboyrules]

Excellent content! do you happen to have your soundcloud or something? Would be nice to hear your music!

[@nscolieri]

I love the music you played while designing the stripboard layout... what is it? :) 7:21

[@MoritzKlein0]

just some random chords i had the finished module play!

[@AndrewGilmour-qld]

tip For your art work you could you modeler tape, it come in 1mm 2.imm , and 3mm roles

[@pkp_tv554]

Couldn't you do the pulsewidth mod with a comparator, so another op amp jnstead of the schmitt trigger inverter, leaving you with a fully used tl074 and just one of 6 schmitt trigger inverters?

[@callum.dokkodo]

This is awesome. I'm just getting into modular, and want to know if these oscillators are easily connected to keyboards/MIDI systems? I want to make a modular setup for my studio and control it with keyboard instead of sequencer. Thanks for your content 🙏

[@MoritzKlein0]

to be honest i have no idea about midi to CV interfacing, sorry! from what i gather you'd probably have to use a microcontroller though!

[@DoctorKarul]

If your keyboard has a CV output it will work immediately. Arturia's Keystep is very popular for this. If your keyboard outputs MIDI, you can get a MIDI to CV converter box, there are dozens to choose from. Cv.OCD is popular. As Moritz said, they use a microcontroller since MIDI is a digital signal.

[@DoctorKarul]

This one is a midi to cv converter designed to match this synthesizer format. www.lookmumnocomputer.com/projects#/1007-midi-cv

[@davidreichert9392]

I love that you do it all on paper, but I would think that it would save a lot of anguish to use software to plan the stripboard layout, something like VeeCAD.

[@easibroeasibrode6381]

Increíble lo útil que es

[@mu8502]

hey my friend I have a question: sometimes control voltage start from 8volt to 10volt(for example) but vco work with 0v to 3v(for example) volt what circuit can convert 8 to 0 and 9 to 1 10 to 3???????

[@bartconinckx]

Fritzing could help in the perfboard design.

[@simonburns1055]

How are you triggering that module when it has no black cables from the sequencer being input into the module ?

[@alebrenna441]

Thanks for this!! Those 10k strange resistors in the left at the ins and fine and coarse are the ntc?

[@MoritzKlein0]

Ale Brenna yeah exactly!

[@theclovercross]

Heyo! been getting into your videos recently. they've been pretty interesting and you explain well for someone like me who's new to electric components and stuff. we're trying to build a modular synth library in the local hackerspace and I've just finished my first LFO! tried a few times to make a simple noise module but that wasn't so simple haha.. but I wanted to ask, what is that Shift module? I'm hankering for some blinking lights for our project. been thinking of implementing digital number displays too in some way. can they be used instead of LEDs? anyway, stay awesome! :)

[@MoritzKlein0]

it's a shift-register based gate sequencer. i'll do a video on that soon! and while yes, you could technically drive number displays with it, it wouldn't work in a functional sense, sorry!

[@theclovercross]

@@MoritzKlein0 I'll be looking forward to it :) I'm not interested in displaying numbers, just using differents parts of number displays as an alternative. we have a load of em here.

[@jackaubone9792]

Did you build that spring reverb? i’m trying to build one right now haha! I’m a beginner to electronics and your videos are so helpful for understanding electronics with audio, thanks!

[@MoritzKlein0]

yup, the driver module at least. it’s fairly simple, i‘ve been meaning to do a video on it!

[@jackaubone9792]

@@MoritzKlein0 that’d help a bunch haha, amplifying the tank the right way is super confusing

[@mo55yoak]

Is there a components list for this one? It would be very usefull!

[@HeegeMcGee]

Awesome tutorial! Can you share a link to your Stripboard layout and the schematic?

[@MoritzKlein0]

schematic is already on my patreon, stripboard layout will be up soon (with some revisions).

[@JKiefer]

Wirklich sehr schöne Videoreihe, vielen Dank, Moritz! Sobald's wieder ein bißchen mehr in der Kasse klingt, kriegst Du noch ein Patreon-Abo :D Was die Beschriftung des Gehäuses angeht -- hast Du mal über Metal Etching nachgedacht? Eine Spannungsquelle hast Du ja, zur Not tut's aber auch eine Batterie, und es ist haltbarer als Lack.

[@ChibikR]

Hello Moritz! I've built your single vco, but when i tune vco like you mentioned in pt. 3(0v then 1v) frequency jumps more then two octaves. I tried to short 1.5k resistor, but this helped only with one octave, next octaves start to drift highly

[@bvcddgtzuii520]

Theres a video about the tuning Process,maybe this helps :-)

[@martingerken7094]

Again, well documented, thanks! PS: where do you buy the tempcos?

[@MoritzKlein0]

you mean the thermistors?

[@martingerken7094]

@@MoritzKlein0 Ja, die meinte ich. Habe sie nur zu Mondpreisen gefunden...

[@MoritzKlein0]

Martin Gerken ich kauf meist bei meinem lokalen händler: www.segor.de/#Q=NTC10k%252Fmini&M=1

[@BackFischKuchen]

Hi, I'm trying to build that module right now, but I can't figure out what you did to the "FM in" from your schematic. Did you just leave it out in the final build or is it connected to something internally?

[@MoritzKlein0]

i left it out due to space constraints!