Reverse engineering the circuit that revolutionized delay effects

[@MrSlipstreem]

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]

Some BBD IC? Just curious

[@MoritzKlein0]

@@MrSlipstreem sounds like a really fun problem to solve. what did you replace the unwanted sounds with?

[@jameslynch8738]

​@@MoritzKlein0He probably used anything other than the tone in the video at #19:20 😉

[@MoritzKlein0]

@@jameslynch8738 🥲

[@gorloxian]

Dude you old analog guys, I am in awe of. My "artist" name is a term from an exotic quad decoder.

[@misterhat5823]

Probably the best explanation of how a BBD works.

[@m.f.3347]

I feel like this video should count for credit towards an electrical engineering course... great work!!

[@Spencer_Sp]

Not enough linear algebra

[@NicStage]

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.

[@MoritzKlein0]

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!

[@MrHerhor67]

Yeah. First it is analog, then discretized, and lastly digitized. This chip/circuit just omits the last step.

[@unknown-zc8be]

Lost me at dry/wet mixer 😮

[@robertosutrisno8604]

Wait this isn't a fully analog circuit? Why?

[@MoritzKlein0]

@@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.

[@chriswareham]

Superb video - this is quality content that makes KZbin worthwhile. I've no desire to build my own BBD based delay, but learning how they work is fascinating.

[@MoritzKlein0]

@@chriswareham glad to hear :)

[@MouldySoul]

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

[@MoritzKlein0]

@@MouldySoul that’s the spirit!

[@BartWronsk]

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.

[@MoritzKlein0]

that’s exactly the balance i’m trying to hit - glad to hear it works for you!

[@ChristianMuenker]

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!

[@bobthecomputerguy]

I totally agree. I haven't touched analog circuits since college as well, but found this super fascinating.

[@costlywidgets]

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

[@MoritzKlein0]

true, but as far as i know the idea lives on in CCD camera sensors 📷

[@thomasdzubin]

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.

[@dcurry7287]

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.

[@MoritzKlein0]

glad to hear, that’s exactly what i’m hoping for :)

[@YDKMPablo]

Reconstruction sampling instead of the traditional hardcore rolloff makes a huge difference in preserving the fidelity, and avoiding clock noise at very low frequencies. This means getting longer delays with smaller BBDs. Night and day... I'll definitely test this approach. Thanks for the amazing explanation and presentation.

[@K.D.Fischer_HEPHY]

You Sir, have become a professional video creator in terms of content and quality. Kudos.

[@meistudiony]

Love this! Great explanation of how everything works, why everything works and in a lot of cases why something DOESN'T work.

[@taidi4038]

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 :)

[@MoritzKlein0]

@@taidi4038 glad to hear you like the front panel design - thought it’s time the modules get some visual spice :)

[@dr.getter7118]

I don't know if anybody mentioned this already, but I am pleasantly surprised by the little doodles and graphics present on the front plate of this new module =) I noticed something similar on the panel of Labor already, and here it is once again with this new eurorack module. Little arrows and squiggles identical to the ones we see in the animations of your videos, Moritz. I really like them, hehe, they give the panels a personal touch without being distracting. Quite elegant too, I have to say. I would like to see more modules in the future come out with front panels featuring similar graphical decorations. Thumbs up from me 👍

[@MoritzKlein0]

@@dr.getter7118 glad to hear, that was exactly the intention! and i do want to keep adding these to upcoming modules :)

[@MusicTechknowledgy]

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.

[@MoritzKlein0]

that PLL chip is seriously feature packed :)

[@stratfanstl]

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.

[@MoritzKlein0]

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.

[@guitfidle]

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.

[@MoritzKlein0]

the pt2399 is extremely complex compared to a BBD chip - that’s why the driving circuit can be so much simpler :)

[@famitory]

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.

[@guitfidle]

@@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.

[@guitfidle]

@@MoritzKlein0 exactly! That's why I had looked at BBD circuits in the past and had no idea what was going on 😁

[@AlexBallMusic]

This is too good to be free on the internet. Outstanding. Awesome sound demos at the end too. 👏👏

[@MoritzKlein0]

hey thanks, glad you enjoyed it ✨

[@alessiocaligiuri]

Amazing video, well explained and recorded. From the first half part, I learned a lot. Just three notes: 1. You completely missed to mention the Aliasing issue, that happens when clock freq. goes below half the maximum frequency of the input signal (Nyquist-Shannon theorem) --> an input LP filter is really needed, tuned wrt the minimum clock frequency. Lot of the sounds of the video come from that fenomenon. In other words, the bandwidth of the BBD circuit is always less than half of the clock frequency, otherwise you will get a lot of 'noise' in the audio band. 2. The two complementary clock signals need a small dead time between their edges (that is, there is always a short time when they are both not active); this is due to non instantaneous switching of the MOSFETs and will reduce a lot the spiking. 3. The flanger effect usually refers to delays that are a lot shorter (in the order of 1ms to 5ms) and the related audio effect is different from what is shown in the video. Apart from these notes, I really enjoed the video and I thank you for such quality contents!

[@iamsushi1056]

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!

[@MoritzKlein0]

good luck with that project, sounds like a fun one!

[@nickwallette6201]

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.

[@sandrainthesky1011]

I have used many BBD chips in circuits along with synths, distortion, fx, for years, and I had a basic understanding of it but it's so cool to see one built from the ground up! Thank you for this great tutorial!

[@MoritzKlein0]

i was really happy when i managed to make it work using JFETs - so useful to be able to check the signal at every capacitor in the chain!

[@janberentsen9890]

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)!

[@MoritzKlein0]

perfect timing - hope the video will help!

[@joshuahernandez5848]

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

[@MoritzKlein0]

oh wow, that's great to hear. 🙏

[@davejackson8376]

As a gear nerd who realised in the mid 80’s that not all BBD delay pedals were created equal, this video is fascinating.

[@swinkatrampolinka5120]

sad4096 ?

[@coreyfridinger8242]

Pitch...swing ... CRACK and OUT OF THE PARK!!! Another brilliant video and teaching session!!! Well done.

[@MoritzKlein0]

thank you :)

[@martinda7446]

That was great. I remember seeing a 'Bucket Brigade' circuit published in ETI back in the late 70s I think. I had no idea at the time what it was.. Thanks for the reminder.

[@miscbits6399]

those ETI circuits were the basis for lot of stuff I built for friends

[@DJRY360]

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.

[@MoritzKlein0]

that's great to hear 🙏

[@sturdyblock]

One the best channels on YT.

[@jakesheath8382]

Your videos are such a huge inspo for me as a synth DIY geek. Amazing as always!

[@andrewdewar8159]

Cool ! I had a bbd it had mic and guitar inputs with volume knobs and the out ouput had a switch for different dB levels so you could use it like a pre amplifier. It had some mental sounds if you did too much feedback, it was quite hissy. I also had flanger and chrorus pedals before the days of digital delays. I had the first digital delay pedal as well when it came out.

[@SmelvinSmorner]

You utter utter legend, always wonder how people deal with the clock noise!

[@lucanotreally314]

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!!!

[@MoritzKlein0]

@@lucanotreally314 really glad to hear :)

[@MarioConsunji]

Thank you so much for this video. As an amateur, ive been looking at how to fix an old dod rds delay, this gives me a better idea on how delay circuits actually work

[@MoritzKlein0]

glad it was helpful. good luck with fixing your delay!

[@scottlarson1548]

Back in the late 70s and early 80s Radio Shack sold a BBD chip for projects. I built the standard one: voice actuated cassette recorder. When audio turned the cassette recorder on, the BBD gave the audio enough delay for the recorder to start recording so the beginning wasn't cut off. But the audio quality of the BBD was barely audio cassette quality. I recall it more like AM radio quality and I assumed that was the cost of using a bunch of capacitors to store audio. I was surprised to hear later on that BBD circuits could actually produce high quality audio.

[@MoritzKlein0]

that's a really interesting use case. maybe they applied really heavy filtering to combat the sampling artifacts and clock noise?

[@timballam3675]

Built one based on a design from Elektor Electronics back in the day. Multi Taps all mixable to the output and feeding back to the input. The clock could also be modulated either internally or from an external input. A friend managed to get it to make a guitar sound like steel drums!

[@MoritzKlein0]

how many taps are we talking? i'd be interested in using a multi tap BBD for reverb, but couldn't really find chips with more than two taps.

[@timballam3675]

@@MoritzKlein0 MN3011 has 6 taps at non multiple spacings along the delay line.

[@theantipope4354]

Looking forward to seeing a mention of the classic MN3001 CCD bucket-brigade analog delay line chip from the 80s.

[@Scrogan]

Only halfway through, but this is looking remarkably like a synchronous dual sample+hold circuit I designed a while ago, designed to be a high-speed peak detector. Also, with a 4046 as your clock source, you could make a comb filter out of it and use it as a VCF.

[@helmargesel3972]

Thanks for explaining how the circuit works

[@stevebunes9151]

Awesome video! Perfect amount of in-depth explanation yet keeping things easy to understand and consume. Great job.

[@markhammer643]

An *excellent* tutorial. Personally, I would have pegged Moritz to be noticeably older than he appears to be. So, kudos on being such an excellent teacher at such a young age! BBDs contain the sorts of stages nicely illustrated here, but the capacitors they use to store charge for transfer, are also pretty small and leaky. That means that clock rates lower than a certain rate will result in enough leakage for the charge that gets transferred to be less and less like the original, the more stages it is passed through, and the more slowly it is passed from bucket to bucket. Ultimately, EVERY bucket brigade chip has a lower clock-rate limit. It also means that they do not and can not "store" samples the way that digital memory can. But there are also *upper* limits to clock rate for every BBD. The input pins for the complementary clock pulses have their input capacitance. That capacitance tends to impact on the shape of the incoming clock pulses, when they exceed that upper limit, such that the "handoff" between complementary sections is not as instantaneous as intended, degrading audio quality. The Reticon BBDs had clock pin capacitances that were a fraction of those used in the Panasonic/Matsushita chips (and Coolaudio clones of them), making them more suitable for instances where one was deliberately aiming for very high clock rates. The V3205 used here is a 2nd or 3rd-generation BBD. Earlier 30xx BBDs were engineered differently, and were aimed at higher supply voltages. The 32xx series will work with +5V. Why the difference? Remember that, in the earliest days of BBD-based effects/processing, while some effects had onboard transformers and a power cord, external power supplies were very much a rarity, and many effects pedals assumed battery operation. Since the DC bias voltage used to make the input to a BBD appropriate was taken from the supply, as the battery wore down, the bias voltage would change. The 32xx series allow the BBD to operate with supplies as low as +5V, even though the supply to the overall circuit might be higher. Regulating the voltage provided to the BBD down to +5V, and deriving the bias voltage from *that* meant that any pedal operating from a +9V battery would be able to function properly until the on-board battery wore down to around +7V. And by that point, it would probably be too weak to power the audio path and any LFO and electronic switching circuitry. Put another way, the 32xx series strikes me as really a solution to problems inherent to battery operation, and not an "improvement" to audio quality, per se.

[@rteune2416]

I bought one of these in the 80s, threw it out a couple of years ago. I was trying to make a delay on voice but after seeing your video I can see where I went wrong😆

[@pirminborer625]

Ok so you just got me interested in diy Eurorack synths. Basically audio lego for electronic enthusiasts!

[@MoritzKlein0]

exactly - looks a little scary from the outside, but super fun once you start playing around with it! :)

[@elluisito000]

Such elegant explanation of a very elegant solution

[@Galova]

For some reason I somehow knew how you look yet I've never seen you before. I imagined you very much like this. Good to see you. And great video too

[@BNLNRD]

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

[@MoritzKlein0]

you should, it's fun :)

[@blacklion79]

Best BBD explanation I ever seen! Thank you!

[@urgon6321]

The obvious thing to do is to use more BBD chips for longer delay at higher clock rates. The clock rate should be more than double the max signal frequency. Then add proper higher order filters to get rid of all unwanted noise. So adding more BBD devices will increase delay at higher sample rates without distortion. Also one can tap signal between BBD chips for more interesting echo/delay effects. CCD chips used in digital cameras work the same as BBD devices, but initial charge stored in each capacitor in line is determined by light level - it discharges them (IIRC). So process of getting the image data from the chip starts by clocking it out across the sensor to the ADC at the end of the line. In case of CCD chips propagation delay is a bad thing, causing horizontal tearing when recording fast movement.

[@stephenspackman5573]

Ah, then instead of modulating the clock rate, you can just manufacture more BBDs … no, wait, that's software thinking.

[@MoritzKlein0]

yes - but unfortunately BBD chips are really expensive. so this is not really feasible for a commercial product.

[@urgon6321]

@@MoritzKlein0 Well, I found lot of ten for less than ten bucks, from China. These are clones, might not have the top notch specs, but are good enough for this usage...

[@miscbits6399]

​@@MoritzKlein0it WAS done in various studio and broadcast kit though. Things got "very expensive, very quickly" in analogue designs

[@jlinkels]

Very good explanation. And thankfully including schematics. Yes, there are people who post a KZbin video showing how to assemble a circuit. Showing the components and the wires and not the schematic.

[@dorjedriftwood2731]

The minute the question was posed I immediately said capacitors, though in my head I imagined an array of capicators that could duplicate charges at different heights of the wave. I’m not an electrical engineer just a guy that watches electrical engineering videos.

[@summerlaverdure]

absolutely amazing, i always wondered about BBD and this explains it in the best way i can understand. thank you for making this!

[@MoritzKlein0]

glad the video was helpful :)

[@CristiNeagu]

These BBDs were a huge breakthrough. I have a book that tells you how to make most effects with BBDs, not just delay. Flanger, chorus, etc.

[@darmstard]

what the name of the book ?

[@CristiNeagu]

@@darmstard Wouldn't help you. It's long out of print and not in English.

[@darmstard]

@@CristiNeagu thank you anyway

[@mikestckl6939]

just out of curiosity , whats the name of the book ?😅

[@adamthedog1]

@@CristiNeagu ok. what's the name of the book tho?

[@CharlesHess]

I built a PAIA “Phlanger” in the late 70s with a bbd. It was quite effective.

[@DeeMacias]

Very interesting video! The more you learn the more you realize you don't know anything. It's incredible how we take for granted things like an echo, a simple effect in audio. But behind there is a microscopic world with brilliant minds that shaped it. And if I think about all the advancements that were made 'till today in every aspect of human life.. that sounds REALLY crazy. We humans should be more aware of the world we live in. It would help us make all the right choices we need. But unfortunately very few people are so intelligent, and for sure no politician is.

[@clacktronics]

The re-sampling so so smart!

[@ninyobro]

That acid pattern is beautiful AF!!!! I either need a full version of it or just the sequence written so I can make it for myself lol. Beautiful video too big up!

[@sjay4673]

What an epic overview! Well done! Keep up the great content, Moritz Klein!👍

[@MoritzKlein0]

@@sjay4673 will do 🙏

[@BenWard29]

There’s also always the all-pass filter for delays. It’s a phase shift, but you can build up longer delays by adding them together.

[@MoritzKlein0]

but afaik it affects different frequencies differently, right? which makes it more of a specialized tool

[@MatthijsvanDuin]

@@MoritzKlein0 A first-order all-pass behaves like a delay in the low frequency limit, specifically a delay that's twice the RC-time, or 1/(π*f₀), but at higher frequencies its group delay decreases towards zero in a non-linear way: if T is its low-frequency group delay then at frequency f its group delay is T/( 1 + (π*f*T)² ). This means the group delay is still 99% of T up to f=0.032/T, but it's down to 90% of T at f=0.1/T, and 50% at f=1/T. The phase error is only 1͏.1° at f=0.1/T but then rapidly increases to 10͏° at f=0.22/T and 60͏° at f=0.48/T. If we pick the f=0.1/T limit and say we want that accuracy in the entire audio band up to 20 kHz, that means a first-order all-pass is a pretty decent delay up to.... 5 microseconds.

[@miscbits6399]

SOOO many memories being unlocked btw one of the things I found very early on was the capacitive coupling between breadboard tracks and the importance of impedance matching between stages (something which became normal as I moved into UHF and SHF RF circuitry but that's a different life chapter)

[@MoritzKlein0]

impedance matching between stages means matching transistors?

[@miscbits6399]

@MoritzKlein0 no. it means the output and input impedance need to be fairly close. A hi-Z input is more susceptible to external disturbances whilst a hi-Z output can't drive much. in RF you end up with reflections and in higher frequency analogue you start seeing these effects too. Closer matching goes a long way towards reducing the sampling spikes For the purposes of circuit design you can treat gates or opamp inputs as extremely high Z and outputs as extremely low Z. adding some output series resistance and input shunt resistance helps match, but at cost of high frequency rolloff due to CR (dis)charge timing curves. It's less of an issue in low gain circuits like a bbd, but there's still _some_ gain and every low-Z/high-Z mismatch will toss in a little distortion and noise (*) Analogue like this can end up being akin to black magic because of all the feedback loops you're throwing into the chain but that's half the fun of developing effects units. The important part is copious notes about what sounds good because it's hard to replicate afterwards The bbd system is in essence an analog electronic computer in the same way a norden bombing or battleship firing solution was an analog mechanical computer (*) that's not necessarily a bad thing if you're making a musical instrument - where these things add timbre to the sound(**) - but it's a huge evil if it's part of a high fidelity reproduction chain (**) for the purposes of music, the amp and speaker chain can be part of the instrument. This is especially true in guitars, where the soft cutoff characteristics of overdriven valves vs hard of transistors and the subsequent harmonic chains generated plus distortions from various cabinet designs are the topic of religious arguments about "what sounds best" where the "true" answer is actually "what the musician prefers it to sound like"

[@electricdawn2258]

This is DIY electronics at its best. Thank you very much for what you do, Moritz. 👍

[@MoritzKlein0]

thank you for watching :)

[@SteveHacker]

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!

[@netluci]

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🎉

[@OllAxe]

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?

[@MoritzKlein0]

@@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!

[@nickwallette6201]

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.

[@miscbits6399]

​@@nickwallette6201did you ever play with surface acoustic wave delay lines?

[@jlinkels]

In the late seventies I built a delay with multiple TDA1022. The application was to time shift two identical audio programs broadcast by shortwave radio transmitters. Transmitting identical programs caused variations of ~ 500kW in power consumption of the transmitters as the audio level varied. That put too much stress on the local power plant which could not handle the load variations very well. Unfortunately the delay was too long for cascaded BBD. The noise level increased too much.

[@carloscardenas2815]

I'm a big fan of your channel and sound and music electronics. I have to congratulate and thank you for the work that you do. I've built and designed some stuff by myself, and plan to develop professionally my own designs too. I found your videos very interesting and informative. Keep it up!

[@MoritzKlein0]

@@carloscardenas2815 glad to hear. what are you working on at the moment?

[@carloscardenas2815]

​@@MoritzKlein0 At the moment I plan to resume some work I've done in the past. I've design couple of synth modules or independent noise makers 10 years ago. But I've only been able to develop one of them in prototype, because of time, budget and life. Nowadays I'm working in technical service doing repairs and operating professional sound and music equipment. But I plan someday finish the ideas I've had 10 years ago, and maybe develop new ideas and someone else's ideas. As a hobby I like to analyze sound circuits. Regards.

[@o3rMeNs]

Thanks so much for sharing your knowledge. Your videos really helped me get a grip on audio electronics and being able to breadboard stuff and modding some of my synths.

[@scottk3292]

Holy Smokes! I have an old 1980s Ross flanger, which had a beautiful sound, but was noisy as heck and then recently died. For some reason, none of the VST (computer-based) flanger effects seem to achieve the beautiful destructive interference which my old flanger gave me, and I've been looking for a good replacement. Your circuit seems to be less noisy than my old unit, and sounds incredible. I'm going to look into the kit you spoke of. If I have any success, I'll seriously consider putting this into a good enclosure for my guitar.

[@MoritzKlein0]

RIP to your flanger 🥲

[@KeritechElectronics]

Hey, that's some really cool prototyping setup :) Nice material on BBDs, I learned a few things. Thanks!

[@MoritzKlein0]

i am extremely happy to not be working on a normal breadboard anymore 🥲

[@oldadajbych8123]

I need such video for each IO instead of (in addition to) datasheet. It is so easy to get the idea of what each pin does.

[@MoritzKlein0]

sure, will take a couple years though 🥲

[@AnimusBehemoth]

These animations are gorgeous. I’d love a quick explainer video showing how you built them

[@MoritzKlein0]

good idea! might do a YT short about this

[@noelwalterso2]

I had exactly the same idea but unlike you I didn't have the perseverance to see it through. It was the whole business of click detection that defeated me. I'm interested to know if you filled the gap with silence or by duplicating the audio immediately ahead of or behind the click. Also if you used zero crossings to avoid discontinuity in the signal. (All things that occupied my mind greatly at the time) Good work to have created a working device that still functions decades later 👍 I'm very glad that you succeeded where I failed.

[@vincentsengel7017]

Great video, thank you. Now i feel like i want to build one (once i make some room in my projects backlog)

[@nibblrrr7124]

19:15 Neither my cats nor I appreciated this +8dB LU increase in loudness. ^^" (Perhaps 10dB lower than equivalent LUFS would be ideal for such a shrill sound.) Great video though - I had never thought about the implementation details of BBDs before.

[@MoritzKlein0]

i am very sorry 🥲

[@apaleslimghost]

Moritz Klein face reveal!??

[@JustPyroYT]

No he has shown his face multiple times in live streams

[@borututuforte]

hottie

[@nilsqvis4337]

I almost spat out my coffee (even though I've seen his face before on his ig)

[@DJRY360]

​@borututuforte I know right?! Too distracting I need just hands and components or I stop learning. . Jk Moritz. . Happy to see your smiling face. This made my day!

[@TeleEle]

yes . a man from ww2

[@petrokemikal]

Awesome work again Man.. Your way of explaining things is on point. !!

[@adamgorka368]

NEW MORITZ I CANT BELIEVE IT OH HAPPY DAY!!!!!!!!! loved it, thanks!!!!

[@robertharker]

Feed the KZbin algorithm with a comment. Great video. Thank you!

[@luke2141]

I just recently ordered Amber on vinyl, nice choice to have at the front of the stack :)

[@fmiramar]

Great explanation! Thanks again for producing this kind of content!!

[@stuartcornall5306]

That is an excellent explanaition of the CD4046 PLL chip. truely excellent!

[@MoritzKlein0]

there is a lot more to it though, but i haven't explored the actual PLL functionality :)

[@kaferere]

In the early 80's, I had the privilege of meeting Jim Mothersbaugh at the Roland R&D department in Los Angeles where he was working. He told me a very interesting story. He said that at one time, Roland were experimenting with Bucket Brigade circuits to see how low they could get the resolution before the sound quality became unacceptable. During this experimentation, a certain feedback resonance occurred with very short delays with limited feedback. They kept a note of it because it's what became the TR 808 Clap.

[@bskull3232]

The Vgg thing forms a cascade amplifier, which improves overall transconductance and reduces capacitive coupling of clock pulses.

[@MoritzKlein0]

i read it’s to combat the miller effect - might be the same thing!

[@bskull3232]

@@MoritzKlein0 Yup, miller effect for high freq response, cascading and also helps stabilize operating point for a better gm.

[@rewIndustry]

in "reconstruction sampling" you are essentially adding a fixed delay to the clock rising edge, to produce another rising edge for your sampler. this is not relative to the delay frequency, and would have to be set relatively conservative, in order to fit within the fastest delay pulses, and the slowest, and seems very clunky, to me. instead, why not generate a multiple of your clock frequency, use a clock divider to get your bucketing pulse, and a counter to derive your reconstruction sample trigger? this way you can ensure the reconstruction sampling happens at the most optimal point, at all delay times. thank you for this video, i have always wanted to know how "analog" delays work.

[@Scrogan]

Yes, using a counter to get phase-offset square waves makes a lot of sense. With a bit of logic you could also ensure that your square waves have a dead-time between them, in case shoot-through is a problem.

[@MoritzKlein0]

that would have been my preferred approach, but in the end i decided to go with “good enough” to keep the circuit as lean as possible. good call though!

[@MarcoGualtieri]

@@MoritzKlein0is there a way of sampling it just before the end of the exponential decay, rather than just after it begins?

[@MoritzKlein0]

@@MarcoGualtieri ideally you would take the clock, apply a 90 degree phase shift (delay it by 1/4 of a wavecycle), and then turn that into a trigger. alternatively, you could also use more comparators/buffers/logic gates to add more propagation delay, but this will break at very fast clock speeds.

[@c1ph3rpunk]

Ok, that Labor board is really cool, have to pick one up.

[@MoritzKlein0]

will be even cooler once the oscilloscope expansion is out (which will happen soon)!

[@robinsutcliffe_video_art]

Thanks, I've been messing about modding a BBD for a while now, it's nice to read exactly how it works, and why two (one inverse) clocks are needed!

[@MoritzKlein0]

@@robinsutcliffe_video_art that mystified me too when i started looking into it. glad to hear the video is helpful!

[@robinsutcliffe_video_art]

​@@MoritzKlein0 It is a very strange though beautiful delay sound, the degradation is lovely. I have made delay selectable between two BBD chips - however At first I had no audible clock, now I have audible clock at certain delay frequencies - Still de-bugging this rather annoying occurrence. Something has changed in the filtering it seems, it's difficult to track down : )

[@MoritzKlein0]

@@robinsutcliffe_video_art godspeed :)

[@robinsutcliffe_video_art]

@@MoritzKlein0 ha ha! Thank you. I will implement your S/H technique as I have another BBD to play with. I believe you have revolutionised the way of working with, and results from, these chips. Well done! Next I will experiment with the companding technique, this improves the S/N ratio a bit. It's described by electric druid and electrosmash

[@zerstaerker]

BBD devices! FINALLY! Thank you so much!

[@ouou456]

heyy, i like your shirt! portrayal of guilt is great. also, thanks for publishing these

[@MoritzKlein0]

devil music is 🔥

[@VAC-u1r]

Dude this is so fascinating and explained so clearly!! Very very cool!!

[@MoritzKlein0]

thank you :)

[@onecircuit-as]

Brilliantly explained. Thank you for such a great video. 👍😀

[@ESP32_WROOM32]

Im a simple man - I see Moritz Klein, I click the video. Now for real, it is probably becasue of you (mainly)! That i started studying electronic engeneering! You are a badass and you deserve every medal for sharing these videos while having a fulltime job running! Cheers!

[@MoritzKlein0]

@@ESP32_WROOM32 thank you so much! hope your studies are going well :)

[@poptartmcjelly7054]

Pretty cool how the BBD chip is just an analog memory chip.

[@MoritzKlein0]

@@poptartmcjelly7054 really bad memory because of capacitor leakage - but yeah :)

[@somedutchguy7582]

​@@MoritzKlein0DRAM is even worse, which is why it needs constant refresh cycles.

[@jeffryarchambeau5441]

Reminds me of the drum storage on early digital computers. Was cells of capacitance that had to be refreshed. Or how about the mercury delay tubes that were used for temporary storage? I'd love to have one of those for an audio delay, just for bragging rights.

[@thisnthat3530]

Very cool. The only thing I would change is the switched capacitors (220p, 1n). I would hard wire the 220p and have a SPST switch to parallel in a ~800p cap. This would ensure there is always one of the 2 desired capacitances in circuit. The current circuit might have open circuit momentarily during changeover. Not sure if this matters though as I have not checked the IC datasheet.

[@guilhemmarty6287]

thanks so much for these videos !

[@marcbrasse747]

26:10 min: “I won’t pretend I understand how this works in detail.” This applies to most information you provide but I am at least understanding the main principles. Charging a row of capacitors with the previous ones charge, eh? No wonder they call it a bucket brigade. But the biggest surprise is that BBD’s work like analog samplers by “Digitising” waveforms. That will scare a lot of analog effect fans. 🤣 One is never to old to learn. Thanks! 👍👍👍

[@MoritzKlein0]

@@marcbrasse747 yeah, it’s basically a stopgap between the worlds of analog and digital :)

[@Bob-1802]

I still have few Reticon SAD 4096 chips in my bin from ~1985. I used them to add some "ambiance" to my music. I should put them back to work (if they're still good) because the circuitry is simple to build.

[@MoritzKlein0]

that does not sound SAD at all!

[@Bob-1802]

@@MoritzKlein0 Well, I probably missed something but, that's the marking printed on the chips. :)

[@MoritzKlein0]

@@Bob-1802 it was just a bad joke 🥲

[@Projacked1]

Dude, you are an excellent teacher 👌

[@paulperry7091]

The concept of a delaying a signal by a bucket brigade arrangement of capacitors predates 1955. I have a copy of the book "A Palimpsest on the Electronic Analog Art" which includes this. It is true that audio applications - and chips - came much later.

[@met0mur]

Как же это круто! Жаль нет столько времени чтобы разобраться во всех крутых вещах. И хорошо что есть те кто разобрался и делится знаниями. Спасибо.

[@aspirin4709]

We want a video on active noise cancellation...Great Video btw..

[@MoritzKlein0]

oh that could be fun! i'll do some digging.

[@nakoradiomies]

This was great! Time to order some bbds!

[@sound.workshop]

You're a treasure! Thanks for all the lessons

[@metalosaur]

Awesome video, and a very interesting reconstruction method! I understood at 28:40 why traditional low pass capacitor was removed (to preserve high freqencies), but why dual tap from the second output was removed? Did it provide any downsides by itself?

[@MoritzKlein0]

simply because it’s not necessary - it doesn’t add much, since the sample-able region is big enough as is!