zynthia - sequencer synthesizer

using a 40106, 4051 and a 4029 to make some noise, following the Logic Noise series on the blog

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using a 40106, 4051 and a 4029 to make some noise, following the Logic Noise series on the blog by Elliot Williams and other projects I found here.

There will be an updated video of it soon, when the parts are all here and the 4028 is in, but since the log with the first video won't show here anymore, I've embedded it here.

Here's the update!

sch - 541.38 kB - 07/13/2017 at 21:48


brd - 108.06 kB - 07/13/2017 at 21:48


sch - 343.41 kB - 07/11/2017 at 21:45


brd - 97.65 kB - 07/11/2017 at 21:45


  • 1 × CD40106 - hex inverter Logic ICs / Gates and Inverters
  • 1 × CD4029B - binary counter Logic ICs / Counters
  • 1 × CD4051B - multiplexing IC Switches and Multiplexers / Analog Switches and Multiplexers
  • 1 × CD4028B - Binary to decimal decoder Logic ICs / Decoders, Encoders, Multiplexers, Demultiplexers
  • 10 × Potentiometer 100k Ohm b/log

View all 12 components

  • 16 step version

    davedarko08/10/2021 at 08:04 0 comments

    I've started to work in KiCad and love to use the buzzard library for labels now. The 16 step sequencer is basically two zynthias (CD4028, CD4029, CD4051) that either count to 8 together or to 16 one after the other. The two stages had to be mixed with an LM358. I tried a TL072 before, but that didn't seem to work. Maybe the LM358 likes DC better as I did not supply negative 12V to the board. I'm using a CD4070 XOR logic gate to be able to invert the second stage with a switch. Still have to route 48 air wires, but I'm getting there. This is a revision, I had the first board for 8 months and was only yesterday able to fi the mixing part of the two stages.

  • more expansion ideas

    davedarko02/24/2020 at 14:18 0 comments

    I was watching a review of a modern sequencer and saw it going back and forwards. Thought to myself I could maybe connect the "overflow" pin of the 4029 and the forwards / backwards selection with a 4017 / 4022 chip. Need to investigate that :D

  • New DIP version

    davedarko01/03/2020 at 19:34 3 comments

    I've been asked for a DIP version and this is basically the latest SMD version with swapped parts and a bigger PCB. Ordered at JLCPCB in red.


    check if C2  needs to be a 10th of current value

  • wiring diagram and BOM

    davedarko10/03/2019 at 10:43 1 comment

    always wanted to do this, but it needed a tindie message to force me to finally draw this.

  • filtering and stuff

    davedarko01/13/2019 at 23:45 0 comments

    @WooDWorkeR  asked me to join the Drehkommando meetup at c-base and since I also had to bring him some goodies from the Chaos Communication Congress, I couldn't say no :D we were able to add zynthia 2.0 to the pile of wires and noise gadgets and it didn't sound too bad. Especially when played loud ;)

    But I noticed some issues that I wanted to work on later. I had no control over volume at all, something I was able to fix with a variable resistor used as a voltage divider on the output. I also had a lot of high pitched noise on the output, something that I wanted to tackle with a High Pass filter. Yes, you've read that right - I was stupid until I noticed I need a Low _PASS_ filter instead :D 

    I then combined it with a simple dc-offset filter - there's also a High Pass filter in the schematics taken from stackexchange.

    Followed by a fixed Low Pass filter and previously mentioned volume knob. You can see spot the two signals here, yellow is coming directly from the 40106, blue is after the filter, but before the volume potentiometer.

    Some slight changes to the capacitor values allow the sequencer to run a bit slower. The synced pitch mode now has a wider range of frequencies. The tone range of the knobs is now deeper.

    With the pink board I also fixed the direction of the potentiometers, when you now turn them clockwise, the tones go up.

    it might make sense to add an external clock input as well, but I want to make sure that any voltages are safe for the trigger level. 

  • here's a little video

    davedarko08/05/2018 at 17:50 5 comments

    working on that youtube channel makes me finish more projects, as it seems :)

  • almost a year!

    davedarko07/24/2018 at 23:15 0 comments

    Wow, it has been a while! I have the SMD boards assembled for a while now, but never came around testing them - I was just not interested in soldering all those resistors and LEDs again to get something that does almost exactly the same like the original does. Until yesterday, when I wired up a 90ies color schemed board :) check it out over here, I'll have a youtube video incoming soon, too.

  • More Zynthias being build

    davedarko09/16/2017 at 16:45 0 comments
  • Rev2 boards are here

    davedarko08/10/2017 at 20:26 0 comments

    I still have to update the OSHpark Board, there are some minor label changes (if it works at all, that is :D ):

    C2 is a 10nF cap

    C1 is a10uF cap

    So this board should have all the bells and whistles it can:

    • 8 LEDs
    • 8 Tone knobs for pitch
    • up/ down switch for the counter
    • binary / decimal switch for the counter (count to 8 / 10)
    • Synced oscillator switchable
    • Speed for the counter potentiometer
    • Sync / Pitch knob

  • Gaaaaah ... it was too close to midnight!

    davedarko07/13/2017 at 21:33 0 comments

    Thanks to @al1 I'm now aware that I've mixed up the GND and VCC symbols from the schematics of @Elliot Williams :D So now it's corrected and everything looks even cleaner! Definitely will sleep on ordering this one (hopefully al1 will have another look, just to be sure) :D I'm not looking forward to the boards arrival - straight to the totem of failure, I guess.

View all 23 project logs

Enjoy this project?



mosoyot712 wrote 06/16/2021 at 10:46 point

Amazing idea I like you thinking. I am also working a very interesting and new idea you can see my massage gun project.

  Are you sure? yes | no

Morning.Star wrote 07/12/2017 at 06:28 point

Bibbity-bibbity-bibbity @ 2:12 made me howl with laughter dude.

Howcome I never saw this before, its awesome! :-D

  Are you sure? yes | no

davedarko wrote 07/12/2017 at 08:22 point

hm, maybe because it's older and I haven't done stuff on it for a while? I wanted to revisit this after MakerFaire, it was a fun attraction :)

  Are you sure? yes | no

oshpark wrote 07/12/2017 at 01:12 point


  Are you sure? yes | no

AVR wrote 07/11/2017 at 22:09 point

I can dig it, music and electronics go well together, skulled and following

  Are you sure? yes | no

Eric Hertz wrote 04/13/2015 at 00:30 point

I dig the 4000-series audio tutorials, too. I haven't yet gotten around to building one, though. It boggles my mind that so much analog-esque audio stuff can be done with a few CMOS (logic) chips. 

(IIRC My hacker-number was 40106 when I signed up... I recognized it was a cool thing to have a CMOS hacker-number, but never knew all this stuff could be done with it!)

  Are you sure? yes | no

davedarko wrote 04/13/2015 at 00:53 point

I might use the 40106 with a digital potentiometer on my R8-D8 project, but I also wanted something "CMOS only". I will try something different with the boards - print a sticker for the top and print out a mirrored version as a guide to solder the wires to the perfboard. And then I hopefully have something noisy/analog/logic synthesizer -ish :)  

so why is it 40107 now? Have you sold 40106 to Muhammad from Indonesia? ;)

  Are you sure? yes | no

Eric Hertz wrote 04/13/2015 at 01:02 point

dag-nabbit, 40107, you're right... (How did you find that out? I couldn't figure out where that info's stored anymore). Guess he's the lucky one.

Ahh, perfboard without copper? Interesting sticker-idea, I look forward to seeing it. (You've seen those little plastic DIP labels they use for wire-wrapping, right?)

  Are you sure? yes | no

davedarko wrote 04/13/2015 at 01:20 point

Hovering over your user name told me this - "My hacker-number was 40106 when I signed up" - sounded like it changed, so I checked what it is now - but it wasn't my intention to check/control you because I did not believe you :) 

Is perfboard without copper? Hmm. I meant the single sided copper boards that are pre drilled. Proto(type)board then? Those labels seem to be very useful, but I can't use them or something similar :( But I hope a mirrored printed sheet helps not losing track while soldering this board.

  Are you sure? yes | no

davedarko wrote 04/13/2015 at 01:21 point

holy moly - it's 3:20 am o.O off to the batbed, batman.

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