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• 16 step version

  davedarko • 08/10/2021 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.

  https://github.com/davedarko/Zynthia16
  

• more expansion ideas

  davedarko • 02/24/2020 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

  davedarko • 01/03/2020 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.

  ToDo:

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

• wiring diagram and BOM

  davedarko • 10/03/2019 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

  davedarko • 01/13/2019 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 https://twitter.com/woodworker/status/1084192948718370816 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. 

  https://electronics.stackexchange.com/questions/319857/anti-aliasing-filter-dc-offset

  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.
  https://www.instagram.com/p/BslYsZqnE6b/

  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

  davedarko • 08/05/2018 at 17:50 • 5 comments

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

• almost a year!

  davedarko • 07/24/2018 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.

  https://www.instagram.com/p/BloIPnCAMTR/?taken-by=davedarkocom
  

• More Zynthias being build

  davedarko • 09/16/2017 at 16:45 • 0 comments

  There will be updates, but here's a sneak peek for @al1  s version:

  https://hackaday.io/project/9038-me-buildingusing-other-peoples-ideasprojects/log/67240-6-zynthia

• Rev2 boards are here

  davedarko • 08/10/2017 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!

  davedarko • 07/13/2017 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.

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