Designing a diode ladder filter from scratch
ฝัง
- เผยแพร่เมื่อ 3 มิ.ย. 2024
- Support the channel...
... through Patreon: / moritzklein
... by buying my DIY kits: www.ericasynths.lv/shop/diy-k...
Complete project on falstad: tinyurl.com/y7eftwyz
In this video, I'll walk you through the process of designing a diode ladder VCF from scratch. Since the topic is rather advanced, I don’t go into great detail about most basic components & what they do. If you are just starting out, I recommend you first watch the rest of my series on filter design. You can find previous episodes here:
Analog Filtering Basics: • DIY SYNTH VCF Part 1: ...
Active Filters & Resonance: • DIY SYNTH VCF Part 2: ...
Vactrol-Based Voltage Control: • DIY SYNTH VCF Part 3: ...
Also, if you need a refresher on how the inverting op amp-configuration works, I recommend watching my video on a sawtooth-to-triangle converter, which you can find here: • DIY SYNTH Quick Tip: S...
If you want to follow along - which I strongly recommend -, here's a bill of materials:
Semiconductors
11x 1N4148 diode
Capacitors
2x 1uF foil capacitor
5x 1nF foil capacitor
ICs
2x TL074
Resistors
2x 200k resistor
2x 100k resistor
1x 47k resistor
8x 33k resistor
2x 10k resistor
1x 2k7 resistor
2x 2k resistor
1x 1k resistor
1x 330 resistor
Potentiometers
2x 100k linear mono potentiometer
Misc
3x audio jack socket
Chapters
00:00 Intro
01:39 Sound Demo
03:49 Diodes as Resistors?
10:31 Bias Current & Trickery
14:02 Multi-Pole Diode Ladder
17:23 Driving the Ladder
25:22 Output Stage
27:42 CV Processing
30:53 Resonance
34:45 Final Demo & Outro - วิทยาศาสตร์และเทคโนโลยี
I hope you are saving all of your wonderful illustrations. They would make a fantastic book.
Reminds me of Forrest Mims' circuit diagrams
@Baylie ϟymms me too!
Honestly I'm not even building diode ladder or anything related to synths, but I love watching your videos, because of how well the videos are made. Good job!
yeah - very cool vid's
*Wow...ONE BREADBOARD???!!! I wasn't expecting that. Seems somebody is German (or maybe Austrian, but that's not so different). Planning to make that. Thanks!*
I’m a traditional old fart. I’ve seen waves of creativity go by over 4 decades of professional life. You are going to be a star. The technology, the art, the dynamic art of the lights, and not least of all, the music, will take you far.
I can visualize a Rammstein album cover, music video and melody based on your work. You should do some demos. And yes old guys listen to them. Metallica paved a path for us old guys years ago.
Thank you for making this series. I have learned more from 2 evenings watching your videos than 40 years of fiddling with electronics. Your plumbing analogy is brilliant. I look forward to seeing many more tuturials from you.
Your demo song actually elicited some emotions in me (besides the standard "that sounds cool" excitement). That's an exceedingly rare thing. Great stuff.
Excellent presentation! I am an electronics engineer, and I love the way you come at your explanations: e.g. the changing resistances of the diodes with current, in the resonator amplifier feedback circuit, and how the stage-gain is reduced at higher amplitudes by 'straightening out the exponential curve'. Very detailed discussion - most (including me!) would have just said 'diode clamp' and not considered the detail! Very helpful for those of us who think we know it all already 😆 Thank you🙏
These videos are really helping to open the doors of analog electronics. I have been wanting to make a filter, and experiment with weird, maybe counterintuitive topologies, but didn't know where to start. The difference between the positive offset and negative offset, plus the placement of the resonance, there is a lot to tune there. I would be really interested in how to turn this into an all pass filter, I have been wanting to get some of those phaser sounds.
yeah that's why i decided to go with this instead of another OTA-based approach. much more room for creative tweaking! (also LM13700s are expensive.)
i'll do a follow up on converting this into other filter types. eventually i'd also like to do a PCB layout when i feel the featureset is refined enough.
@@MoritzKlein0 the fact that this design doesn't use any fancy components means I will likely be able to design a pcb to be assembled by JLCPCB, and have them do most of the components.
That was probably the most technical video yet but definitely the most musically useful device you have created yet.
This filter works really well. The other day one opamp on mine apparently failed. It's cool how these analog devices can sound nice even with a major damage. The sound was similar to warm distortion on a guitar. I suspect the reason for the failure Is that I modified the CV input and might be causing it to go way high on voltage on the ladder. Thank you for your work again!
Iam a mechanical engineer by major, the way you explained electronics made huge sense, I wish we had this 20 years ago, thanks for the good content
Waking up to this on my birthday was a very good thing! Awesome explanation as usual!
happy birthday!
Your explanation of the circuit design is excellent.
We've all been waiting for this! Thanks.
This is crazy cool, THANK you for making high quality detailed videos like this.
"oscillation salad" what a wonderful term!
I already have a decent amount of experience with VCFs, but I still learned something from this video! Your design is honestly brilliant-it's like a further simplified Steiner-Parker filter; your filter doesn't use a differential ladder, so it'll be much more stable with regards to temperature.
I'll probably try my hand at a mathematical analysis of this filter soon.
love to read what you come up with! also - amazing channel name!
@@MoritzKlein0 I'm busy on the Arp 4072 filter as of the moment, so it might be a bit before I getting to your filter. I'll let you know when I start on yours
These videos are incredible. You do a fantastic job of teaching how these ideas work in a simple to understand way. I hope you have a great rest of your day
A lovely sounding filter.
Being an electronics engineer, I can say that such sound and simple explanations for analog circuit design are tough to find. The logical flow and simple language helps one to be a 'part of the design process'.
That sounds great! Simple design too. I did one ages ago by taking a state-variable filter and replacing the two cutoff frequency resistors with boring old diode bridges, and basically doing the same positive/negative control voltage you've done across them. Worked really well too, plus you get low/band/high-pass out of it.
Schematics pls jojo
@@finonomastropiero4261 Demo and a schematic from when I made it -> th-cam.com/video/Z4o3QnJdoys/w-d-xo.html
Good to see your channel grow up. Great video as allways! Have a nice day mr. Moritz
Excellent explanation and I really like the emphasis on the motivation rather than just describing the circuit.
I breadboarded this today and it sounds absolutely awesome. I want to build a euro module but I'm afraid your next version is going to be even better!
Any breadboard layout schematics? Been trying to decipher what is in the video onto a breadboard style layout. Thanks in advance, if can post a reliable diagram of that.
You, sir, are a fantastic teacher. Please keep making these videos. I hope you'll one day do a similar breakdown/comparison of other filter types, like the Moog transistor ladder, or late MS-20 OTA type.
transistor ladder is next on my list!
Wow, I've never seen better explanations for synth electronics. These definitely help me fixing some quirks in my DIY modular! Thank you so much!!
So much work in this video! Can't wait for the high pass filter!
I liked the moving representation of the circuit on the simulations page, I always wonder how it flows, now it is clearer to me, you are the best!!
This is awesome! Thanks for being so thorough in your analysis.
Loving all your videos, really helpful in understanding signal flow and how everything works, appreciate your sharing of knowledge dude!
The best video explaining the diode filter I've seen so far! The style of your videos is very charming and it helped me learn a lot. Thank you!
My choice is pretty limited in terms of getting photoresistors too, so this filter would be a nice option.
Just discovered your channel and I love it! You've reawoken the DIY synth spirit within me 😁 Also, loved the sequence, sounds almost 303 like but not. That's the cool thing about diode ladder filters; they sound rubbery and acidic.
I love your presentations and learning unthincable new in my analog knowledge and experience. Thanks!
Great tune. Would love a longer version
You’re my favorite TH-camr after this!
Awesome, my first Synthesizer was a Korg Poly800.
This is the first video I saw of you. Your talent is marvellous!
Both good at explaining electronics and making music. Awesome!
Greeting from the Netherlands
Just wanted to say your channel is amazing.
I was searching for this kind of analogue electronics explanations all over the internet.. you really granted my wish. I hope you will cover more in future.
Thank you very much.♥️+1
I've come late to the game and your series here, but as a fan of ELP, Kraftwerk, and synths, I am absolutely fascinated! Your explanations are PRICELESS!!!!!! I am a hobby musician and have some electronics background, as well as a new scope I want to get to know, and your videos are PERFECT as a companion!! Very very well done, very consistent videos, and wow, I can't say enough good!!!
Just did my homework and watched this again before the upcoming premier.. this sounds so good, I must have one!
this is an awesome demo on how a diode filter works!! thank you!!
This is wonderfully explained Moritz, thank you. Subscribed
This was a really, really great video and explanation. Thank you for making these!!
For being an excellent musician your are an excellent electronic guy!!. Hats!
Love your channel...
So now I need a comparison of various capacitors in a SEM state variable filter please!!!!!!
Less than a minute into your video and I've subscribed. I'm going to enjoy this channel!
Part of what makes it nice is the synesthesia with that scope. Without the scope visuals in synch I'm thankfully generally over that sound.
I had no idea diodes could do so many things. Transistors get all the glory.
Thank you so much for making these! Such fantastic help!
Thank you! You have great teaching skills. Can you make a video about OTAs and their use in MS-20 filter type?
Hey man I think I’m gonna build a pedal for my bass around this using an expression pedal for control. Super neat stuff
Yessir!
Earlyer I know nothing of this now i know always! You are so good
That Demo was on point.
yet another excellent tutorial. Thank you.
There must be snow on your head, caused by your coolnes =)
Can`t wait for more, Mr. Klein!
Beste Wishes
I'm fascinated by the fact that so far, there hasn't been a single sighting of expensive transconductance amplifiers. I'm sure they'll be used in the future, but it's nice to know there's a lot of good control possible with bog-standard opamps. Well done man. This series is truly inspiring.
1. The "transconductance" op-amps would be needed if the filter's steering element was a BJT.
2. "Transconductance" amps are essentially amps pushing a set amount of current through the load...
3. ... which means you can do it with a "normal" op amp and some fancy feedback loop, if you don't mind part count explosion.
4. Internally they're current mirrors, so replacing them with discrete transistor pairs/trios would probably work too, for that old-school, wobbly sound.
@@MoraFermi Oh I'm aware OTA's are usually used in combination with a bjt, just loved the fact that there's a feeling of it being slowly worked towards. Parts explosion is fine in that case, because it facilitates the style of the video. More parts means less multi-function parts, means easier to wrap the mind around. Don't get me wrong, I do be liking the wobblies too, but I have a feeling this series is working towards more accurate modules later-on. Ideal diodes (Jim Patchel) in place of the split "dual"-filter elements would be a nice way to get the filter's "around 0v" area more linear (as well as it being a nice intro to waveshaping/folding).
tldr; Yes :D
This is a great explanation! Thank you!
Awesome presentation and impeccable english! Thanks for posting :)
Jeez man that kick sounds absolutely lush.
Moritz, you are my new hero. WOW... just wow
This will go down as the most approachable German engineering to ever exist 🤘
lovely filter!
Very clear appreciate the content
been waiting for this one!
4:14 このディオです！
The more polite Dio, after jumping out of the bushes and saying "boo" to surprise Erina on April Fool's.
This sounds like something Burial would make. Good work man, learning so much from your videos.
once again great great great video!
Thank you. Informative and easy to understand .
Very impressive!
Thank you.
Keep these videos coming please :)
I built a nano-amp scale ammeter using a 1N4148 diode. It works great! I use it in high voltage work to measure very small currents
Hi Moritz, thanks for another great video! First off all: I would buy your drawings in an art gallery if they were signed by you :-). If you plan to build a stable and good "pro-version" in series, please consider the use of diode-arrays in one case. This allows good traking and temperature behavior and some are available in DIL or SIL-cases for easy prototyping. Cheers from Kaulsdorf, Christoph
great idea, thanks for the suggestion! i'm planning to do a proper PCB & panel once i've added at least a high-pass (and maybe a band-pass) option, so i'll probably use such an array then!
Super series, Moritz! But I will suggest making a 0V reference line, so it gets a little more clear, how the waves are behaving.
you mean on the offset oscillations diagram?
@@MoritzKlein0 Yes, and the Odd/Even diagram as well.
Thank you for this series. Really motivates me to do electronics, after a long period only programming.
@@Qhotex yeah true, in hindsight that would've been clearer.
wow that sounds good!
Unrelated to the topic, but I like the way you drew all the "S" characters. Great video!
Half S, half lightning bolt
I like it
Fantastic videos!
Looking forward to the follow-up
I really like the technique, it's not something I've come across before, and I can't wait to try it out!
At 26:11, I'd have given the non inverting stage the gain and made the inverter unity gain. That way, you're not amplifying the noise from the first stage with the second.
this would make it much more complicated to get the resonance amp's gain right unfortunately!
Muy buen proyecto!!!!
felicitaciones!!!!
Another great video
Thanks!
i thought you'd end up having some noise problems because of the amplification but it turned out fine!
amazing video as always!!
if that wasn't the case i'd suggest zener diodes
the ones rated to 3.6V would require a lesser reduction of volume (if i got the workings of the circuit right)
so you'd have a greater separation between the signal and the noise floor during the amplification stage.
might be a good idea to try this since the output stage definitely is susceptible to picking up noise. you can keep it to a minimum by using proper decoupling & keeping the big gain op amp as close to the PSU as possible though!
Fantastic video!
Very interesting, thank you.
Great Video.... now where is that dang bag of diodes!!
50-pole filter, let's go!
This video is amazing.
*URGENT!: I need to pack (including the electronics assembly area) to go to another country and I need to get that filter functioning properly before I do! I finished building it on a protoboard (with similar layout to a breadboard, although an extra rail on top and bottom and some on sides), but it’s still not functioning yet. Sigh. That was as much work as building a small building with the right tools seemingly. And I know a building would actually function properly. Sadly the filter hasn’t functioned at all yet seemingly. There was a high pitch sound from some points on the board when had the dual supply a little low. Sadly no potentiometer has done anything to make it output sound from what is seemingly the output yet either. Was SOOOOOOO MUCH WORK. Sigh…*
I have REALLY learned that I should ALWAYS have PCB made when making any electronics circuit that isn’t as simple as most guitar pedals. And then also prefer to have a proper PCB.
Anyway, here are the photos. Maybe there is something obvious simple and easy issue on it that will be easy to solve. The dual power supply is at maybe 11.87V.
Note: Swapped the ground and other rail on the side with the row of caps. Didn’t install the audio ports yet, simply using wires straight to speaker and a 555 synth. Disregard the other circuit on left of the breadboard, as that is a multistable vibrator that isn’t connected.
Thanks in advance for advising SOON on how to make it start functioning! Tested continuity all over the place, although didn’t go through maniacally methodically to confirm all continuity at every single point in that circuit. Underside has no bridged columns and that is a breadboard style stripboard. So it’s laid out based on the final breadboard schematic in that erika synths manual for that filter. (version 2.0 of that manual)
Photos are on imgur. Sadly youtube was deleting any comments with imgur links, so change the [dot] to a ".", obviously:
imgur [dot] com/a/KFrPShY*
I made some iOS apps with a VCS3 filter emulation and taming that filter from going straight to full peak was a process. I may cover the ear that has some tinnitus when testing that filter on a breadboard. It’s like the sound of something flying up into the sky and then suddenly vanishing from this simulation
excellent video!
Thanks' for posting!Great video! : )
Next step could be the differential configuration with transistors as diodes like in TB-303.
Excuse the language, but this is Fking genius! To the others that also understand engineering, you know what I mean......Carry on please. I just had to drop my 2 cents.
Greeat explanations! Thx so much!
aphex twin would love that one, very clean sound
New sub! That's the clearest explanation of a ladder filter I've ever heard. I finally get it now. Thank you! Also, I noticed your homebrew synth seems familiar... perhaps similar to another synth in the Kosmos? 😁
true, the next iteration will hopefully be a bit less derivative!
@@MoritzKlein0 Nothing wrong with standards. I understand Sam published them for people to use them.
Fantastic!
Wow amazing.
I need this 😱
Very good understandable knowledge. I saw your videos dont have any youtube monetization advertisements, you should activate it via settings
i keep that turned off deliberately, since i got a decent number of people supporting me on patreon.
@@MoritzKlein0 👍