Moritz Klein - 2024-10-16
Build your own Delay as a DIY eurorack kit: https://www.ericasynths.lv/shop/diy-kits-1/edu-diy-bbd/ LABOR in the Erica Synths Webshop: https://www.ericasynths.lv/shop/diy-kits-1/edu-diy-labor/ Support the channel... ... through Patreon: https://www.patreon.com/moritzklein ... by buying my other DIY kits: https://www.ericasynths.lv/shop/diy-kits-1/ Simulation in CircuitJS (discrete component BBD): https://tinyurl.com/2dbdonlb Join my Discord community: https://discord.gg/KCwpyAsFpb Here’s an interesting problem: how do you create a delayed duplicate of a sound without recording it to some sort of storage medium? Back in the days before digital signal processing and cheap, abundant memory, this was a prime engineering issue. Until two Engineers named Sangster and Teer came up with a deceptively simple solution: the bucket brigade delay. In this video, I attempt to reverse engineer the architecture of a classic BBD, recreate a bare bones version on the breadboard – and then use a proper BBD chip to design a simple DIY audio delay. If you want to build along, here's the bill of materials: BILL OF MATERIALS RESISTORS 2M2 x1 100k x8 82k x1 56k x1 51k x1 47k x1 39k x1 22k x3 10k x2 6k2 x1 4k7 x1 CAPACITORS 1 uF x2 10 nF x1 1 nF x1 (more if you want to build the discrete component BBD!) 220 pF x2 TRANSISTORS & DIODES 1N4148 (small signal diode) x5 J113 (N-CH JFET) x1 (more if you want to build the discrete component BBD!) POTENTIOMETERS 100k (A104) x1 100k (B104) x3 10k (B103) x1 CHIPS TL072 (dual op amp) x3 V3205SD/MN3205 (BBD 4096) x1 4046BE (PLL) x1 SWITCHES SPDT (Single pole, double throw) x1 Chapters 00:00 BBD Overview 01:43 Analog Sampling 10:09 Sample Transfer 16:28 Buffering & Listening 19:50 Dual Tap Reconstruction 23:01 More Stages with the V3205 27:55 Reconstruction Sampling 33:26 Dry/Wet Mixing 34:41 Feedback 36:04 Flanger Mode 41:43 Inhibit CV 42:59 Sound Demo & Outro
Not only from the technical perspective, also the filming, illumination, motion graphics, narration quality, used didactic tools... absolutely beautiful. This video is a piece of art
Music is one of these wonderful unions of science and art! Moritz is master in this domain!
This is a higher quality explanation and demonstration than you would likely find in a university. Really nice work.
What I love about the BBD is that it blurs the line between digital and analog; Two things that most people consider to be sort of mutually exclusive. You get a quantization of time, but the amplitude is fully analog.
agreed – plus i love how simple it is, especially compared to something like a PT2399. BBDs really feel like a super precise solution to one specific problem!
Yeah. First it is analog, then discretized, and lastly digitized. This chip/circuit just omits the last step.
Lost me at dry/wet mixer 😮
Wait this isn't a fully analog circuit? Why?
@@robertosutrisno8604 it depends on what you understand by analog & digital. since a BBD is splitting the signal into samples, you can make the point that it is digital on the x-axis (time) – since the signal is divided into discrete blocks. the y-axis (amplitude) is still analog, though.
Superb video - this is quality content that makes YouTube worthwhile. I've no desire to build my own BBD based delay, but learning how they work is fascinating.
@@chriswareham glad to hear :)
dammit I'm the other side of nerd, now there's a youtube video let's 'ave it, try and build one as well!! :P
@@MouldySoul that’s the spirit!
Incredible video, can't believe information like this is available for free.
From engineer to engineer, thank you!!!!
This is too good to be free on the internet. Outstanding.
Awesome sound demos at the end too. 👏👏
hey thanks, glad you enjoyed it ✨
Probably the best explanation of how a BBD works.
I feel like this video should count for credit towards an electrical engineering course... great work!!
Not enough linear algebra
Yess
This is an AMAZING teaching video. I have basic electronic knowledge and understood everything. Even if you’re not looking at building a delay/echo system, there’s many basic electronics lessons contained in this video so it’s a good teaching lesson.
SO many instructional videos will just say "We won't do x because it causes problems." and move on. The way this video makes the problems happen and demonstrates why they're an issue before fixing them makes it such a great educational resource.
glad to hear, that’s exactly what i’m hoping for :)
As a gear nerd who realised in the mid 80’s that not all BBD delay pedals were created equal, this video is fascinating.
sad4096 ?
I feel obliged to start this journey. Ive found the teacher that talks as an engineer not just plastikman
One the best channels on YT.
Man I wish I had this video when I studied opamps 30 years ago. All that abstract theory makes so much sense with a practical example like this.
Sampling the signal again at the BBD's output is genius! I also love the creative front panel design. Amazing video and amazing kit as always :)
@@taidi4038 glad to hear you like the front panel design - thought it’s time the modules get some visual spice :)
I really appreciate the level of detail in your videos. I studied as an ME but my work involves a lot of EE knowledge that I've been learning on the job over the last couple of years.
The graphics in your schematics, specifing what chips you are using and why, and just explaining you're overall design process actually helps me be better in my job.
Looking foward to more videos, truly
oh wow, that's great to hear. 🙏
As expected, another superb video from Moritz. I got just as much out of your knowledge of the PLL as I did from the BBD circuit approach. Fantastic. Thanks Moritz.
that PLL chip is seriously feature packed :)
What is crazy is the BBD is old technology now. But the analog nature allows for some charming quirks and actually great analog interfaces compared to microprocessor based solutions. Being that sound lives in the analog realm and the lack of code is great. An amazing build thank you
true, but as far as i know the idea lives on in CCD camera sensors 📷
...which have been almost completely replaced by CMOS image sensors today.
YES! I've been asking for a BBD video several times, and right as I wanted to try my own hand at it, a wonderful Moritz Klein video appears to help clearly explain everything about it! Thank you for these videos (and this one in particular)!
perfect timing - hope the video will help!
This is just amazing. The video came out super clear and ultra interesting. By FAR the best one you've uploaded, keep doing this please! Thank you!!!
@@lucanotreally314 really glad to hear :)
This channel is brilliant 🤩, so much talent and passion, thank you for this amazing content.
Love this! Great explanation of how everything works, why everything works and in a lot of cases why something DOESN'T work.
You Sir, have become a professional video creator in terms of content and quality. Kudos.
Best BBD explanation I ever seen! Thank you!
Great video! Thanks for making it! I’ve built a couple PT2399 delays, but that chip contains much of the external components needed here. I had wondered why BBD delays were so much more complicated. For anyone interested,look up the data sheet for the PT2399, it shows a very basic delay that really just needs a voltage regulator,a couple caps, couple resistors, and a couple pots. It’s a fun and easy circuit to play with.
the pt2399 is extremely complex compared to a BBD chip - that’s why the driving circuit can be so much simpler :)
the PT2399 is notably not a BBD but in a way it's sort of the logical next step. turn the signal into a binary stream using delta-sigma and then you can use a really long shift register and cut down on how accurate/big the capacitors and transistors of each "stage" need to be on the die.
@@famitory yeah, I'm quite aware of that, but it's the only real frame of reference I have to compare it to. And while it is digital, it was designed to emulate the sound of the old bucket brigade type sounds. A lot of the control options are pretty similar too, such as being able to drive the clock speed with a modulated source, the raising and lowering of pitch as the speed is adjusted up and down, and the gradual darkening of the signal. It also does some wonky distorted sounds when you try to make the delay length more than it's designed for, similar to what he did in the video.
@@MoritzKlein0 exactly! That's why I had looked at BBD circuits in the past and had no idea what was going on 😁
@@guitfidle The PT2399 is analog in the same general sense as a BBD. Both can sample and reproduce any analog voltage, not just discrete voltage levels as with most other ADCs. So the PT2399 is not really 'digital' any more than a BBD. It's a great chip! Except when you need very short delay times.
Really interesting as an audio programmer to see this weird transitional tech between analog and digital. Top video.
Awesome video! Perfect amount of in-depth explanation yet keeping things easy to understand and consume. Great job.
Your videos are such a huge inspo for me as a synth DIY geek. Amazing as always!
Your channel hits the perfect sweet spot of "technicality"! (At least for me - I studied EE/CS, but since college, I had zero experience with circuits and forgot all the annoying transistor calculations)
Still engaging, skipping on some of the unnecessary details and calculations, but not "dumbed down" and just perfectly enough to appreciate the beauty and smartness of those designs, explaining exactly what was challenging and how it was solved. :)
And while this might not be enough to build such a circuit entirely from scratch without your designs, it's again perfectly enough of a starting point if someone wants to dig deeper.
that’s exactly the balance i’m trying to hit - glad to hear it works for you!
Exactly, I teach analog electronics and digital signal processing at university and I'm always dumbstruck by Moritz didactic quality. I do recommend his videos to students and colleagues!
I totally agree. I haven't touched analog circuits since college as well, but found this super fascinating.
Such elegant explanation of a very elegant solution
Amazing! I’m finally trying to take my electronics knowledge from the most basic beginner level repairs to actual design/engineering, and I just discovered this channel. Can’t wait to watch EVERYTHING and learn all I can! Also looking forward to getting and learning with this trainer you show here. Thanks! 👏🏻👏🏻👏🏻 … Would you consider (or have you already) making a video explaining your beginnings, and how you acquired your electronics education and experience? Thanks!
Hut ab! Deine Videos sind wirklich wertvoll; da steckt so viel Zeit und Liebe drin! Hab mir gleich mal ein paar deiner Kits zum Nachbauen bestellt!
I learned so damn much in this video, was just getting the hang of the basics of circuitry and this put so much of the basic knowledge into place. Combined with the real examples and argumented decisions at each stage had me hooked. Thank you for this!
NEW MORITZ I CANT BELIEVE IT
OH HAPPY DAY!!!!!!!!!
loved it, thanks!!!!
Wow. I’m just getting started in learning electronics as it’s something that I’ve been interested in knowing how things work for a while and whilst I found it a bit difficult to follow along with at some points I understood the majority because you delivered the content very well. An outstanding video thank you for creating it. Now I’m going to check out your filter videos 😊
I’ve always wanted to design a BBD with a variable output filter tied appropriately to the clock frequency. This is a great point to jump off from and an amazing general learning resource as always. Thank you for your continued work on increasingly complex projects!
good luck with that project, sounds like a fun one!
I had thought about this with some variable sampling rate DACs too. It's on my "someday" list to experiment with adaptive filtering on the Sega Genesis PCM channel to settle the "muffled vs. scratchy" trade-off of different audio circuits used over the console's lifetime.
As a software developer and music producer, this was a great history lesson in how we got to where we are today with digital effects. It was fascinating to learn that even before digital effects, sampling was the only good way to delay an analogue signal purely in circuitry. It's like half-way digital, we got discrete steps in the time dimension but not in the voltage dimension. The capacitors are essentially memory, just analogue memory. Incredibly cool!
Now if possible, combine this with the Nyquist-Shannon sampling theorem and you could eliminate the bitcrunch-like effect of the stairsteps from the sample-and-hold. You would need a variable frequency low-pass filter whose frequency is tied to the clock speed such that it filters out frequencies above half the clock speed. Now, I have no idea how you make an analogue variable frequency low-pass filter or if it's possible to link it perfectly to the clock speed like that, I just know the theorem, not the electrical engineering. It would be interesting to see that explored though, maybe an idea for a follow-up video?
@@OllAxe someone pointed out an interesting idea for that: take two VCFs, control them with the same voltage, set one of them to self oscillate, turn the cutoff frequency offset down to half on the other. then filter 1 is used as the clock, while filter 2 processes the input signal. this should (in theory) do what you’re asking for here!
It comes around full circle -- capacitors ARE memory. That's how RAM works. :-)
Also, it's not entirely true that you need sampling for delays. There are components in old analog video processing circuits that use distance as a delay mechanism. It's (obviously) a very short delay, but it's just enough to solve problems with timing between luminance and chrominance signals, for example.
It all goes to show just how much easier this stuff is when you can just digitize the signal... which is why everything began migrating toward digital as soon as it became financially viable to add an ADC/DAC and DSP or a microcontroller.
@@nickwallette6201did you ever play with surface acoustic wave delay lines?
Great Job Moritz. And thank you for your videos that manage to inspire even the most experienced sdiy nerds, like me. big up for your work🎉
What an epic overview! Well done!
Keep up the great content, Moritz Klein!👍
@@sjay4673 will do 🙏
These videos are masterpieces not only of engineering but visualization and narration / explanation / education. Thank you. I bought a couple of bucket brigade chips to experiment with building a chorus effect pedal and was puzzled why the chip data sheet recommended use of a specific related timing IC. This explained why a dual clock source is required.
i think low output impedance on the clock generators is also important (cause the mosfet gates do pull in current when switching on). so that’s also why they made those special companion chips.
Really love these videos, can't wait to get my Labor here soon and start messing around with some of these edu-diy circuits
absolutely amazing, i always wondered about BBD and this explains it in the best way i can understand. thank you for making this!
glad the video was helpful :)
Thank you so much for this fantastic video. I'm new to electronics, but this has really helped me understand how bbd works. Your insight and ability to communicate a complex subject clearly is exceptional. I'm going to have a go at building this on a breadboard.
Thank you 👍
Just found your channel. Top notch teaching. I am now a subscriber.
Holy cow, the video production, the animation, and the crispness of the explanation... This is just fantastic. I might get into Eurorack after all with your "mentorship"... :D
you should, it's fun :)
I am building guitar pedals, not eurorack, but still you are the most helpful resouce currently available and an endless source of inspiration. I have watched all your videos several times and each time come away with some new, deeper insight.
So thanks for making this available. Thats what i am trying to say.
that's great to hear 🙏
how is this video so effortlessly cool and well thought out
Excellent explanation of BBD operation, intricacies and 'pathologies'! Thank you for the fine detail description. Also, great use of PLL 4046 using all the internal functions, while NOT making a PLL from it!
"Here's a BBD that has four buckets. It takes up my entire breadboard. Here's an IC 1/100th the size my breadboard with 4096 buckets."
the scary part is that enthusiasts BUILT discrete BBDs on dozens of breadbosrds and got to discover the criticality of both component tolerance selection and wiring lengths. BBD chips greatly improved the ease of building things
Feed the YouTube algorithm with a comment. Great video. Thank you!
@MrSlipstreem - 2024-10-16
I used to use high quality BBDs (clocked as fast as they'd go to keep the quality up) as part of an analogue signal processor. This allowed me to monitor and process a signal in real time a few milliseconds before it got to the listener. Using an analogue discriminator and comparator, it was possible to recognise a scratch on a vinyl record just before it got to the output and replace it with something else less offensive to the human ear. Another comparator tracked the average background noise level from the vinyl, so the system became fully automatic with no need for any twiddly knobs to adjust anything.
This was back in the late 80s, and I can still remember to this day the satisfaction of designing it all from scratch (pardon the pun). It took a few weeks to iron the bugs out, but the finished project still works very well to this day.
@Galova - 2024-10-17
Some BBD IC? Just curious
@MoritzKlein0 - 2024-10-17
@@MrSlipstreem sounds like a really fun problem to solve. what did you replace the unwanted sounds with?
@jameslynch8738 - 2024-10-17
@@MoritzKlein0He probably used anything other than the tone in the video at #19:20 😉
@MoritzKlein0 - 2024-10-19
@@jameslynch8738 🥲
@gorloxian - 2024-10-21
Dude you old analog guys, I am in awe of. My "artist" name is a term from an exotic quad decoder.