Saturday, May 8, 2010

DIY 8 Step Sequencer



If you've done the MC-202 mods then this could be a nice addition to your setup. The sequencer is very cheap and easy to build, it's based on the "baby 10". I did a few modifications and plan on making more in the future along with a proper front panel for my modular (right now I used an old cd cover).

I think the total cost of the project is around £10-15 pounds, the main cost being the potentiometers. The mods I did to mine are a 4 step switch,a reset button and output attenuation (it was outputting 12 volts which is a bit hot for my gear). There's scope to add switches to disable steps or output the clock pulses, you could even add a mutli switch to set the last step or set ranges on the output. The scope is only limited by your imagination.

Here's the original article that was inspiration for this project.



And some useful links

electro-music
fonik
audiomidi

8 comments:

  1. indeed, i also forgot to mention there's an error in the schematic, the pot on the far left has its wiper connected to ground which obviously shouldn't be there.

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  2. Thank you for posting this, im having trouble getting mine to step correctly. Ive got the clock enable pin tied to ground which should just let it keep stepping as long as it gets a clock signal correct? If I connect the pulse from the last decode out it seems to run randomly or too fast for it to appear right. This should be a very simple circuit but maybe I have the wrong power supply? Ive tried 12V 200mA, 12V 500mA, and 9v 600mA. Both the 12v psu's seem to put out 15.8-16.2V

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  3. sounds like the psu's you have are not regulated which could account for the weird behaviour. I'm running mine from my modular power so its very stable. You could get yourself a regulated psu, they are slightly more expensive but it should smooth out the supply. Also dont forget that the clock threshold is approximately half the supply rate (mine is actually around 6.5v) and if your clock pulse isn't that much over that level it will cause the seq to run erratically.

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  4. Okay thanks, I seem to have gotten it sorted out. Im not using a regulated psu yet but I know that was giving me some issues. I also noticed that whenever im close to or touch the trigger wire the sequencer runs at full speed. I think if I get a regulated psu with the right voltage it will be more stable. Thanks

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  5. I'm working on building my first one. I've been building synths for a while now, but I've never built a sequencer. Hopefully I'll be able to make my analog creations play themselves. This is gonna be awesome. Thanks for the post. I have a copy of the schematic hanging above my work desk. I noticed the wiper to ground, and figured I'd leave it disconnected as it didn't look right. I'll post an update once I finish the project.

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  6. Great article. My favorite bit is at the end where the author says it will add to any synth especially a lame duck like the sh-101.

    How times change.

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