Designing a DIY synth arpeggiator with logic gates: Part 1
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- Опубліковано 15 кві 2020
- Support the channel: / moritzklein
A detailed look at how to build a scaled CV arpeggiator with a multiplying digital-to-analog converter and a few logic gates. It can be used with any volt/octave analog synthesizer. In this first part, I'm laying out the basics of digital to analog conversion.
If you want to follow along and can't find the TLC7524, the AD7524 is a good replacement that might be easier to find.
Here's a rough bill of materials:
1x TLC7524/AD7524
1x TL074 (TL072 would also suffice I guess)
1x 4040 Binary Counter
4x LED
4x 2k Resistor (exact value doesn't matter as long as it's not too low, just to protect the LEDs)
2x Audio sockets (big or small, doesn't matter, up to preference)
For the voltage divider:
2x 100k Resistor
1x 27k Resistor
1x 10k precision trim pot
(I know these values differ from what I have in the video, but I guess picking higher resistor values wastes less current)
Any questions - feel free to ask them in the comments. I'm happy to help. - Наука та технологія
this is a way more chilled out version of LOOK MUM NO COMPUTER.. and I love both of them ;P
I am now totally immersed in this channel and Look Mum No Computer awaiting a delivery of parts.
great video Moritz!
I love your use of sketches to illustrate what you want to achieve and what an IC does. Great video.
Your sketch style reminds me of those Engineer's Mini-Notebook books by Forrest M Mims. Very cool way to explain things!
had to look him up - there‘s definitely a resemblance, good catch! and a nice compliment, thanks!
Those books are great!! I was just talking to my wife about that after watching some of these videos.
Nice to see and hear some playing up front - kind of a "why we go to the trouble" moment!
Thank ypu for the great combination of music, math & elctronics!
Great video, can’t wait for more to come!
What an actual dude this guy is, a proper dude
These are fantastic. Incredible and practically done explanations. Super useful. Excited for more.
Great video, learned a lot! Saw you on the synthdiy reddit. Keep up the good work and please post more of these!
This is really great stuff! The ideas are genius and well thought out, and it's clear there's a lot of effort put into it.
Great video! You are really good at explaining how these ICs work!
I love these video’s. They are really helpful for all those that are in to synth diy, understanding electronics in general.
Your level of explanation is so refreshing.... subbed👍🏻👍🏻
This is the best logic gate lesson I’ve ever had. I’m going to watch all the other videos. Thank you!
Found this on reddit. Great video, really informative and I think I'm going to use it to get started on a DIY eurorack.
Amazing channel, happy to find it! Keep up the good work!
This is pretty great, cleanly explained and presented; Thanks!
Dude I love your channel, I was definitely expecting an Arduino circuit! Keep up the amazing work
I recently fount this new channel and i am so happy and thankful. It is so good and organized, very original and very rare. No stupid animations or non logical explanations, everything done in old good way on paper, nice analogies and then tranfered into practice. Keep it up, very good and original.
Thanks from Chile! i'm a novice but thanks to your videos i understand more about the world of synth. I hope you make much more videos!
This is so great -- thank you! I'm inspired to try making one.
Your tutorials are really great - thank you so much! 🙏🤩
Thanks for the video, I always wonder how keyboard works, you break it down in details and build one from ground up, two thumbs up 👍👍
Another great video mate. Top work.
Great build and tutorial bravo 👍
Great videos
Great explanations
It's so cool to see the displays turning on and off on the keyboard as the systems multiplexes to show the proper value for each 7segments
Just wow ! you're 2 series are amazing I was wondering if its possible to do a series of your diy modular that we see in your first series that would be aaaaawssooome!
you mean like a tour/demonstration video?
@@MoritzKlein0 yes and teach us how to build each individual module like your 16 step sequencer, filters, vca, vco, vcf, adsr generator ,etc.. thanks
Just ask to others if they will interested in that kind of video series and I'm sure they will be easily convinced to jump in !
@@MoritzKlein0 I second this. Your channel is incredible, I've been recommending it to all my students
Loved it, thank you
Tu canal es oro puro!
you are my inspiration thank you for this video
Love your videos and straightforward clear explanation. One thing I don't understand is why and how op-amp works as a voltage buffer. Next occasion perhaps?
check my vco-series - i have an in-depth explanation in there!
This is so amzing
Useful, inspiring Thanks!!
I have to say that the demo starting at 01:53 is really beautiful. It has actually haunted me (in a good way) and I've had to go back to it a few times to enjoy it. I really like your arpeggiator design - I can see me tackling it, or something similar very soon. It should be easier for me compared to the analogue electronics. I'm also thinking about how I can incorporate my 65c02 (Ben Eater) computer!! :)
Great video! I got some Jean-Michel Jarre vibes from your first demonstration.
great teacher
Wow, the music at 1:50 is beautiful!
My first reaction was "why not quantise the CV signals from your analogue sequencer". Bu then we wouldn't have got your great explanation of how to build an arpeggiator :-)
Great vid
nice, I started messing around with cmos logic gates a couple days ago for syncopated rhythms. Today, I was using a 4013 dual flip flop, cascading the first into the second. One is clocked normally and the second one is clocked by this PLL prototype I ve been working on. Also, the PLL uses a random slewed lfo into it's input. It ''humanizes'' some of the patterns. I m a newb that's discovering the amazing things you can do with chips that weren't intended for these uses at first. Your arps vids are the next logical step. I need a DAC first.
So this is why every module has a TL074!
buffering is really essential!
@@MoritzKlein0 - in the case of simply buffering, can I use an lm358 instead of a TL072/4? I generally try to avoid them because, while I have a benchtop power supply to get +/- voltage, I want to be able to just use a 9v adaptor for the projects I build.
Tan Stowell any op amp should do. though you can definitely use tl07X with +9v and ground. just make sure you don’t feed it any negative voltages then.
went hard af at 2min
You are a genius
Wonderful video! Thank you so much. You mention the keyboard or finger board on your synth, how could you incorporate the fingerboard into the oscillator instead of the stepper? Could you use it as on or off switches, or let's say triggers, to operate or trigger specific frequencies instead of the "sequencer" triggers?
Look Mum No Comput..... Wait... thats a different channel :D As the others said, Amazing way of explaining how all this works
I love the old-school oscilloscope. I have a nice DIY DSO that's cute, but I keep firing-up the old B&K beast on the bench. Even for digital at times...
same - has that charming retro-sci-fi feel
I've been watching your stuff for a while. For some reason thought you were a really old Russian man.
Привет
Loving these projects! What part do you like to use for the "small signal diode" in the parts list for this module (three of them in total)? Is there an ideal forward voltage for that part?
thanks for your very good channle
Hi! How are you? I hope that very good! I am from Argentina and I have been following your videos and I saw that you have a very clear way to explain, you make good didactic transpositions! I wanted to know where I could find the schematic of the circuit to recreate it, and ask you if I have to have a VCO or how I can use it since I still do not have any synthes module and I found this work very good to apply the issue of gates logical.
I have a question: So far to use 5 1/3v ref we will get the maximum of 64 notes (5oct n 4notes) with max 6bits for the tlc 7524 but what if the ref voltage is 10 1/6 instead and we take 7 bits out is this possible to get a 10 octave range from the IC?
yep, no problem!
WOOOOOO min 2:03 blow my mind!!!
Awesome, are you using Kosmo format there on your module synth? Thanks for the video man.
yep! eurorack is a bit to small for my taste, and i like the look of quarter inch cables more.
Hello Moritz, hope you're doing well! I've spent the entire afternoon trying to wrap my head around a problem I'm encountering with this build:
When I reach the 12:19 mark, I do read 5.33V on my multimeter, but changing the values of the counter reduces the voltage, as if the OP-AMP wasn't doing anything. I was measuring at the output of the OP-AMP, but trying other points had the same effect. I am using 9V batteries, since that's what I started with when watching the VCO series, but I don't see why that would be the cause.
I've started from scratch twice now, and I keep running in the same problem, at this point I'm very confused.
Thank you so much for doing these videos, this along with your VCO series are a great introduction to electronics, which looked very daunting and complicated in a previous life :p
Hey there, I finally got around to trying this out with a TLC7524 and I have built it exactly as you have, the only difference being a +9/-9 power supply. No matter what I try I cannot get the perfect ramped scale as I should. Any idea why? I divided 256 by 9 then by 2 and by 2 again, and tried it at 7.1v for the reference voltage and even divided it again and tried that. My scales are not working at all and I am certain I have not made any mistakes. Any ideas/help would be most appreciated!
P.S. What happens is it plays a C at 0000 and then a C# and maybe a D and then a C and then E, F C, D, C ... something like that.
EDIT: I found the "error" but it is still a mystery... I changed the breadboard and it worked... All exactly the same but the original breadboard did not like the circuit haha!
This is the frustration and mystery of electronics. Sometimes the problem is a goddamn breadboard and you will lose your mind until you figure it out.
I Enjoy a lot with this music ! In Farsi we say کیف کردم
Could we also use the multiplying DAC and some extra circuitry to give our scales different melodic modes? It'd be challenging but worth it to think of a way to have custom LUTs accessed by a small cheap FPGA or CPLD that could theoretically allow an infinite amount of custom modes.
Also I'm guessing that parallel arpeggiators would be required to make a chord, but have you thought of a way to do unison without all the extra hardware? I feel like op-amps have a purpose here but I'm unsure what the actual hardware would have to be. Perhaps at the end of the day you'll need multiple VCOs that all drone differently relative to the primary tone.
👏🏼
wouldnt it be possibble to to quantize the potentiometers with schmitt triggers? Not really sure though if itd make sense component count wise
not sure i get the concept - how would you go about doing that?
@@MoritzKlein0 sorry, had the wrong idea of schmitt turning off when voltage is too high.
Comparators might work though. If you use one for each note and set the upper and lower threshold, it leaves room to have blind spots or overlaps on the potentiometer in terms of notes. No forbidden states as they are simply not allowed but 1/note comparators, so economics will decide up to which point it makes sense
hi, how to add CV modulation to the release and attack of the Quad AD/AR?-
that's a rather complex topic, but if you want a quick & dirty solution i'd say use vactrols!
The bit outputs of the ADC0820 will only be going between 0-5V (LOW and HIGH) but the TLC7524 (if it is powered by +12V) will need a voltage which is higher than 5V to read its bit inputs as HIGH. At least i assume that is the case based on the data sheet. Did you get the TLC7524 to work with just 5V coming into its bit inputs?
🤩
How about we want play higher notes thant D#1? Is it possible to still use that IC , or it will be a different IC that will be composed of 32 bit? Thank you
16 bit rather
Du bist so cool
Looks like the DAC08 chip might also be a good alternative. Can anyone confirm?
Could you use this to make a quantizer?
yeah, check the third episode in this series!
So why do you ground pins B2-B5 on the TLC7524/MDAC instead of say B0-B3 or B1-B4?
Sorry, didn't word correctly, I meant to say why do you use those pins, not ground.
Ok, I watched it over again, this time without doing something else that requires my attention, lol, and I think I understand it now, B0 and B1 are used, it's just that you always want them to be read as 0 so they are permanently set to that state, correct?
genio
I'm no electrical engineer, but an idea: maybe use 12 bits for all the notes, and then use the other bits for things like changing octave, empty notes or changing the note value to half/quarter or other stuff like that? i do not know how hard that would be, but hey worth a try maybe
12 bits is 4096 steps. If you mean 1 bit per note, you can use something called a priority encoder to take the "highest" note and convert that into the binary number equivalent (4 bits which lets up to 16 states). For octaves you could use a parallel shift register to shift all the bits the number of octaves. Shifting left is equivalent to multiplying by 2.)
Dude. More videos.
Seems like the accuracy and stability of vref can affect the accuracy of the notes.
yeah totally!
@@MoritzKlein0 have you experimented with using a low noise vref like LM431? I wonder if it would create some interesting behavior.
Thanks! Quantizer!
i hardly know her!
My only criticism is that in analog you CAN have the standard tunings, it's just not a simple circuit.
inviting discussion on why opamp buffers instead of transistor? (i'm not touching anything that conducts until my oscilloscope gets here to make my own observations on THD vs transient response) i suppose there's not much difference in price anymore..
www.diystompboxes.com/smfforum/index.php?topic=37165.0
it's neat to finally see the little round channel pic. i thought it was a closeup of a guinea pig's nose :)
I think that is because transistor buffers usually drop 0,7 volts at the output, and It is not desireble...
I don’t get what is wrong with an arduino
not as exciting
Schade, du bist 50 Jahre zu spät geboren worden! Ich kann mich noch an die gute alte experimentelle Zeit erinnern! Wir, die Kinder lauschten wie paralysiert den Klängen der Oszillatoren und träumten von Minimoog und Co.
It is much beyond my knowledge. Thx anyway.
So having such beautiful god ! Why not be happy ?
couldnt you have used tubes for pure analogue arpeggiator?
In common synthesizer parlance, this is a "quantizer", not an "arpeggiator".
We all have only one God who is beautiful and likes beauties as his prophet muhammad said it about him! Of course like other beautiful things this beautiful music also origins from his beauties !
I will admit I find it a bit sad that you are going to all the trouble (trouble in the modern sense, given that you can just go and buy an Arduino) of building an analogue modular synth, but then you decide to fix your sequencer to 12EDO, which is an ugly (and recent) musical compromise to keep keyboard instruments cheap. I can't help but feel that, for conceptual uniformity with the VCO, this should ideally be done with analogue components or, failing that, at 12+ bit resolution so that the available pitches are perceptually smooth.
Otherwise-I mean, if you really believe in 12EDO-it might have been easier to make the VCO work with a counter and talk to it over a digital bus! ;)