Designing a double wavefolder from scratch

[@stefansynths]

Quick tip regarding the jittery triggering on the scope with the folded signal. If you connect the input triangle wave to the second channel and trigger off that, the triggering will be rock steady. The channel doesn't need to be displayed to be used as the trigger source.

[@MoritzKlein0]

oh good tip. will do next time, thanks!

[@scottramsay3671]

Yeah, a classic eurorack scope technique (even recommended in the "mordax data" module manual) is to use the square wave output from your vco for the scope trigger, literally can't ask for a cleaner trigger than that.

[@emiliaolfelt6370]

@@scottramsay3671 im still gonna ask for it

[@emiliaolfelt6370]

@@scottramsay3671 you can't stop me scott

[@JKTCGMV13]

@@emiliaolfelt6370 please no don’t ask humanity cannot handle that knowledge

[@alexanderhuliakov6012]

That jam in the beginning is outstanding. I'm a big fan of such lofi house.

[@DarkMetaOFFICIAL]

I always unfold my waveforms when guests come over

[@gamma_noize]

One thing, that just came to me: You're dipping into West-Coast waters here. Maybe that could become an interesting series and a bit of a contrast to your existing videos covering mostly East-Coast modules like ADSR, filter, saw-core VCO. A video about Lowpass-Gates and maybe a series about a triangle core VCO, as those are more common in the West-Coast-Domain. I'd be especially interested in the triangle core vco and through-zero FM. Quadrature oscillators based on sine and cosine could be a very interesting topic as well. But anyways, so far i've learend a ton from each of your videos! Thanks for that! :)

[@lebasson]

I have to rewatch this a few times to fully wrap my head around it but on thing's for sure: you are teaching me things about how transistors work that I never knew before. Or possibly you're explaining it in a way that for the first time allows me to understand how it works. Awesome!

[@Reuben1024]

Absolutely fascinating so simple in essence but so clever, I didn’t realise how wavefolding was done

[@mrwalter1049]

Very Nice! You are very good at explaining these in "layman" terms.

[@primussoa]

love the loma prieta record big ups skramz king

[@carterpochynok4874]

Ive been working on my portfolio projects to go back to school for music technology and your channel has been a godsend. The reverse engineering videos in particular are amazing for giving context to my electronics technician certification classes. Having a bunch of audio circuits explained and broken down into their most simple states has been a huge help in deciding how I want to design my projects.

[@myblues]

I've been anticipating this video for a few months. Thanks for your continued dedication!

[@myblues]

Could you, in theory, combine two of these circuits for a 2.5 x 2 = quintuple wavefolder?

[@MoritzKlein0]

@@myblues sure!

[@amrkoptan4041]

There is a sense of Nostalgia in your music and I haven't heard someone that talented for a long time, thank you for this great video!!

[@iamsushi1056]

Yayyy! I’ve been waiting for this!!

[@ahmedalshalchi]

Genius ! .... I LOVE analog electronic designs and signal processing ... Thank you for this free course ...

[@gamma_noize]

Oooh! That's how it works! Thanks for explaining it in understandable language! 😊😊 This folder is pretty similar to the folding cells of the Metalizer which Arturia uses. Well, at least if i remember the old YU-Synth schematic, which sadly isn't available anymore. Probably, because Arturia has gotten the exclusive rights to that schematic. Iirc the Metalizer cascades four stages of the buffered folder circuit. In front of the folders is an exponential VCA to set and modulate the level of the input signal and an amplifier at the end to pull up the level back to typical eurorack levels. I knew the circuit, but didn't understand it. Now i know what it really does.

[@fatihnomore]

That's the channel I've been looking for! I'm a student whose studying electronics engineering and trying to create music like IDM and other electronic genres.

[@nickcaruso]

my dog's mind was blown by the wavefolders.

[@my4trackmachine]

Great jam in the beginning! I am surprised at how simple wave folding is. It’d be cool to make a multiplier at the beginning of the circuit so you could blend the original output with the old. You could add a break point from the mult so it could be an additional in for if you wanted to blend a different wave shape in. I could build that with multiple modules but it would be a cool all in one as you could use it as a basic mixer as well. Great video! You’re a good teacher!

[@FFuss0]

I'll be making this today

[@DroneDrummer]

Did this for my volca modular. Some things to note! I had to switch the 1 resistor next to the potentiometer. I replaced the 100k with a 30k and a 6k8. I also changed the resistance at the output. Really really fun and opens up volca modular to be an actual modular synth. Make sure you get a scope. I did this without a scope at first and realized after getting one that pnp npn are polarized. I also added a bypass switch. Super cool build!

[@tombrews]

nice little jam in the beginning there!

[@DaftRebel]

Thank you for making all this information easy to access to everyone!!!

[@yunyun2451]

I love your Legowelt-style demos!

[@benjoe999]

One day I will watch all of your videos!

[@steveroberts1861]

Once again a clever but simple circuit. Thanks Moritz.

[@Medniex]

Awesome and clean video. This really inspires to get hands on some DIY projects and kits again.

[@JKTCGMV13]

Beautiful presentation

[@MrTheog1989]

Very cool! I was looking at wavefolding recently, but the idea of additional wavefolding stages never crossed my mind!

[@starblocks5479]

repping the T69 Collapse vinyl at 0:20!!!!!!!!!!!!!!!

[@philtipping]

Excellent video thank you. Very clear and well paced... and really appreciate you not smothering it with meaningless background music like so many other tech-talk videos :)

[@tourtravel2624]

Very good teaching

[@0911paul]

Oh man thank you so mutch!

[@memes_of_production]

Awesome! In my investigations into wavefolders a few months ago I found schematics close to your design, though I had no clue what was actually happening between the two transistors. I eventually built a wavefolder with a ton of clipping diodes and two summing op-amps to get those nice folds, though.

[@_trupples]

i find it very interesting how similar the circuit looks to a CMOS inverter, and it kind of makes a bit of sense, but is still mindblowing

[@DominikKristen]

Very cool! Great job!! 🔥😎👍

[@luisangelrosasperez4801]

Aphex Twin FTW ❤

[@vintagetubeamplifiers]

This really taught me alot, thank you.

[@ThermalWorld_]

Holly molly... You burn my brain 😝 "Awesome explanation"

[@jakobhalskov]

So well explained; you are getting better and better with these videos :) As I've said earlier it is great inspiration for my electronics and KZbin endeavour. Best wishes.

[@Pandangus]

Thankyou for the knowledge! Can't wait to build one myself :D

[@nmidu]

lovely as allways my friend mortz. big hug from argentina

[@achimbuchweisel2736]

Wow, I did not know that the transistor acts this way :D

[@lolaa2200]

yet another masterclass :)

[@buka9330]

Great video, I might try to build such circuit for fun. Also that jam at the beginning is just simply addicting. Will it ever be released as a full track?

[@MoritzKlein0]

i plan on releasing full tracks after i'm done with the erica synths collaboration!

[@libervolucion]

This is great, thank you.

[@Blah53455]

That kick

[@lit2021]

You are a godsend! :D Thank you so much for all your tutorials.

[@DroneDrummer]

At 7:57 you say to connect a 20k resister to the positive and one to the negative but in the video you connect both to the positive. Am i mixing something up or are you using the upper + marked rail as a negative? Does this project use positive, negative, and ground? Or just positive and ground?

[@DroneDrummer]

I see my issue. It's positive, negative, and ground, and im only using pos and neg. I found your dual power supply video, but I'm a little lost on how to set up the ground. Would you mind linking a video if you have one that explains it a little bit for me?

[@GravelVoice30]

It's been a while now and I've noticed that you still haven't gotten into using OTAs. OTAs are very useful in synthesizer electronics. For example, an OTA based VCA in place of the first op amp would be a good way to introduce CV and modulation into the circuit. Anyway, I think you are doing a fine job in helping people get into DIY circuitry. Keep up the good work. 👍

[@KeritechElectronics]

So simple and yet so cool. And again, I hope I learned something :)

[@morgan0]

after starting the video and seeing the bit about folding a saw to a triangle, i had to try it with a lowpassed saw. kinda annoying to set up in vital but it sounds pretty cool. cool and simple schematic but it seemed a bit different on the top and bottom, maybe that was from the triangle being imperfect

[@FFuss0]

Thank u so much

[@avcimustafa7052]

Hallo ! Moritz Klein. Danke für deine arbeit , ich finde es sehr interessan.

[@Sarahbuildsstepsequencers]

Moritz, hope all is well in your life!

[@user-oh4yj5xk2h]

~ 9:20 - pnp = npn's "bizarro twin brother" 😂 yes!

[@McTroyd]

Really cool! And unlike a diode mixer, you only need one oscillator to use it.

[@jpakaerc]

Hello!!! Thank you for this really interesting tutorial, there are a lot of DIY on the modular, but there is never an explanation on why the choice of components and their usefulness! sorry for translation i am not english

[@jeffcannon7763]

Would this circuit also fold a sine wave input? Or would separate modifications be needed? Excellent and wonderfully educational video, by the way!

[@MoritzKlein0]

it’ll fold any kind of signal!

[@jeffcannon7763]

Awesome, thanks! Very inspiring!

[@torsteinnordstrand170]

Sweet! What's the best way to control this with, say, and LFO?

[@MoritzKlein0]

easiest way i can think of is routing the input wave through a VCA before sending it to the wavefolder. since the intensity knob is just an attenuator, varying the input signal’s volume is functionally the same as turning the knob.

[@torsteinnordstrand170]

@@MoritzKlein0 smart, thanks!

[@knuteri3]

Very nice circuit and video! A quick question: Will matching the Vbe of the transistors matter?

[@MoritzKlein0]

if you want the result to be perfectly symmetrical: yes. but i don’t think that’s really necessary. (then again, i haven’t tried it, so i can’t say if there’s a big difference in tone!)

[@3MEu]

Hi! Thanks for the cool stuff. I try to build it and face some obstacles. I match very closer values of 20k resistors to get rid of offsets, put to base of 1st stage transistors signal with max value ~1V. But on the collectors (of 1st stage) folded signal has big offset (down to minus) that goes bigger on op-amp (up to positive voltage). Because of this offset folding has no symmetry and very fast runs to extreme. Incoming triangle has symmetry. The same on 2nd stage. I try use different pairs of transistors (pnp+npn), I check many times that pins connected right, attenuate power levels for pls and minus but offset still appears. Do you have any ideas/tips about this - what can be wrong or to fix it?

[@DroneDrummer]

Finally got my 12 Digilent and got this working! Super cool and very fun! I notice if you turn the knob all the way down the signal is lost at about half way on the potentiometer. Is that how yours works? Or do you get the full range of the potentiometer?

[@DavidRoyal1000]

Nice demonstration! Did you study electronics?

[@MoritzKlein0]

no, i’m self-taught.

[@DroneDrummer]

Awesome video! Want to use it with my volca modular but concerned about the lower voltage it does -3.3 to +3.3. Any suggestions for changes that would allow this? Would a voltage divider at each end to raise the incoming and lower the outgoing voltage work?

[@soundlimit300]

Very interesting,what changes would I need to run on a +15v -15v supply.Cheers.

[@MoritzKlein0]

none - it should work just fine!

[@bclare2544]

Thank you.

[@F3RNI]

Thanks, I made this module 💜 Everything works perfectly, but there is something. As the threshold increases closer to the maximum value, the volume of the output signal also grows strongly, reaching up to 19 VPP. And at the lowest threshold, the signal is centered below the 0V. I think I need to play around with the values of the resistors near the potentiometer to limit the range. Anyway, thanks a lot for the detailed explanation!

[@F3RNI]

as BJTs I used BC547 + BC557

[@neodimium]

I wonder... How would that sound with guitar signal. Something similar to distortion? Or more like compressor? Or combination?

[@MoritzKlein0]

my guess would be harsh distortion, but i haven’t tried it!

[@neodimium]

@@MoritzKlein0 I doubt it would be (too) harsh... As regular distortion makes almost square wave from guitar signal which is almost pure sine wave. Fuzz is even worse. It has clipping diodes in opamp backfeed. But I never checked how it looks on scope.

[@Necrocidal]

Like an octaver plus a load of hissing

[@DrJ3RK8]

Another fun twist on this, is to put VCAs in front of both (or more) stages, then add a mixer at the end with a dry signal. ;)

[@mpingo91]

Moritz, this is going to be off topic, but there is no video of the output module yet, so I have no choice. :D Do I think correctly that a buffered mult, such as Doepfer A-180-4 or similar, supplemented with an attenuator on the input will be able to be used as a headphone amplifier?

[@Poulscath]

Very nice, I learned quite a bit about wavefolders from this. I have to ask though, are the pots linear or logarithmic?

[@massimookissed1023]

Pots are usually linear unless specified otherwise. Looking at the user manual for this circuit's kit from Erica Synths, they are all linear pots.

[@massimookissed1023]

Linear pots are marked with the letter 'B' eg B10k Log pots are 'A'

[@cooksoni.a]

nice loma prieta record 😜

[@jackiboi307]

Do I see an aphex ep there? Doesn't surprise me at all, I've kind of thought of you as an aphex twin enjoyer lol. Your last profile picture reminded me *a lot* of the come to daddy cover

[@MoritzKlein0]

eagle eyes!

[@DarkMetaOFFICIAL]

hey man this is really cool! I am thinking about how I can do this with a typical software synth. Maybe If I created a new type of custom modulator, but it would have to be high frequency, and synced up and locked to whatever the actual duty cycle of the waveform is playing at any given moment. So if you have your triangle wave, the mod will dip the peak into an inverted triangle mod shape, turning on and off at the mathemathically precise timing to be synchronized, symmetrical, and aligned. I think it would work. I know I can create those types of shapes with a tuned graphic eq on a very high resolution. I have never thought of this. But it reminds me of some fx plugin I used to have, it could add narrow band harmonics, or carve them out of the spectrum, in different shapes and q curves. This is a really interesting video. I love innovating new audio ideas and learning new stuff. Thanks man

[@rodgre]

Okay. This was awesome. Now how can I implement this to use as a guitar processor?

[@FFuss0]

Hell yes!

[@carneeki]

Here I was thinking "oh we could do this with a comparator and an inverter". We probably could, but that might need more op-amps. Might play around in circuitjs and give it a whirl though.

[@DroneDrummer]

Building this later today. I have a pre-built 9v power supply. Will this still work? Or should I build a 12v? Thank you for all the help!

[@MoritzKlein0]

i think it should work just fine with a 9V supply!

[@DroneDrummer]

Awesome, thank you!

[@66Gollum]

Wondering what will happen, if one use this as a guitar effect? But maybe it will noct work, simply because of the big differences of volume

[@DroneDrummer]

Is this possible with a single power supply, or does it have to be a dual power supply? I figured out my other issues. This is definitely the main cause a 5v single power supply is not enough.

[@summerlaverdure]

can i plaease buy the intro song on bandcamp or something

[@Luca-pm4ri]

loma prieta 😲

[@myblues]

Serious Question Alert!!! Is this the end of the line for Moritz Klein designs? Maybe a second row of "mki x es edu" would be cool! like; PT2399, LFO Trig/Gate seq, drums, phaser?

[@ciro_costa]

How does this circuit handles offset waves?

[@philippgrunert8776]

Is there any literature to learn this type of information to design circuits for audio?

[@DroneDrummer]

Built it, but i don't get sound. Looks like my power supply is actually a 5v output. Is that my issue? I followed the diagram for the negative and positive connections. I noticed in the video there were some that didn't match the diagram. I'm 90% sure it's the power supply. I get a sound (Not the synth) out and then it drains the power supply and shuts off.

[@mynameismynameis666]

nice low-fi detroit vibe

[@MarcoNeuber]

Hi Moritz, the manual says: Now you can proceed with calibration, which consists of adjusting the multiturn trimpot. Please, follow instructions above! There is no instruction? Would you be so kind and helping out with the steps to calibrate this little monster?

[@KangJangkrik]

Can't believe electrical engineer actually did this, I thought it was only at software

[@mmooee999]

Would any of your breadboard designs run on a 9v battery?

[@Necrocidal]

Tweak some resistor values, set up a virtual "ground" at 4.5V using a decent opamp + capacitors - should be doable. Guitar pedals do stuff like this (they usually run off 9V). Other option is to DC/DC the 9V to ±12V using something like a RECOM RTD-0912.

[@nmidu]

yesyesyes

[@onpatrolforthejuice]

AFX for the win 7\ 7\ 7\

[@zerstaerker]

In Deutschland produzierte ICs werden übrigens liebevoll "Kartoffelchips" genannt.

[@t1d100]

Kewl

[@Sevetamryn]

Couldn't this called a kind of octaver?

[@Barnaclebeard]

I thought this was going to be about wave soldering.

[@tiempoveganoprovida2247]

Demasiados componentes... mejor me compro una quena

[@simonburns1055]

fluff and fold

[@incxxxx]

Too much words. No stopping. No breaks. Its tiring.

[@Necrocidal]

There's a pause button ☺

[@xasdrubalex]

Came for the wave folding, stayed for the Loma Pietra LP 🥹