7400 drum machine is a delight

[74hc595] just finished his entry in the 7400 logic contest. It’s a drum machine built entirely from 7400-series logic chips. He hasn’t quite reached full completion of the project yet. The hardware works just fine, and he’s built a foam core face plate with many more controls than you see here but much of the circuit is still on a breadboard at this point and only two of the channels have been complete thus far.

Jump to the video clip after the break to get the details of how the system works and to hear it in action. This demonstration is one of the best we’ve seen for a synthesizer project as he actually talks about what each control does, and how that is accomplished with the hardware. We’re not going to go into detail about the circuitry he’s designed. As we said before, it uses 7400 logic but also sources a 555 timer to keep the beat. The page linked above has a PDF of the schematic available and you could really lose a lot of time studying how he did this. We might even try to build it in a simulator to see what we can learn.


  1. Ragnar says:

    Impressive already, and with 4 channels will sound so even more.

  2. oodain says:

    very impressive
    i like the sound of it a lot

  3. Andy says:

    Love the sound it makes and the build.
    Reminds me a lot of retro games

  4. Harvie.CZ says:

    Very nice.

    I’d like to see DIN sync (and maybe also MIDI sync) for this, so you can jam together with other machines :-)

  5. M4CGYV3R says:


    Roland called. They want to hire you.

  6. zuul says:


  7. rktokomak says:

    this creation will put me in a trance, i do not need a biofeedback machine.

  8. Mhoriarty says:

    SO intense.

    I wonder if Digikey has a grab-bag of like 5 of every 7400 chip…

  9. Simonious says:

    Very nice.

  10. abobymouse says:

    Is he selling these? He could EASILY kickstart this and make some money.

    Especially if the system sold was modular – buy sound generators for each channel (and they don’t have to be “drum”; they could be “bass machine” type); the sequencer; etc.

  11. Kiddi says:

    What would be a good software package to simulate stuff like this in?

    Awesome project :)

  12. matt says:

    Thanks guys! (I’m the creator)

    Turning it into a kit would be a very cool idea–especially as a modular system–but I’d use an AVR for the sequencer. Some of the parts (esp. the 74C922 and 74LS189) are prohibitively expensive and not available in quantity. If I made a nice case with slots for plug-in modules it could be sweet.

    I couldn’t find any simulation software up to the task, I just built it on the fly using datasheets and a logic analyzer. Logisim is promising, but doesn’t supoort the full line of 74xx chips, and seems buggy. I used Paul Falstad’s circuit applet to design and simulate the sound generator though, that worked pretty well.

  13. matt says:

    very nice

  14. Addidis says:

    Really nice project. This is what I thought of when I saw the contest. Basically a little Subtractor drum synth from Reason.

    I like this the best of any I have seen so far simply because of the fact the end product is actually a nice useful piece of equipment.

  15. dl7und says:

    Wow, can’t wait to see with in action with all four channels…

  16. Aristo says:

    Man… this would make the most badass asteroid music

    Love it man hope you win

  17. Nate says:

    omg, 3:15 seconds, those sound like some old firing noises when you play games like 1943 on nes or afterburner on sega :D

  18. Roel says:

    Add midi and you have a cult instrument :)

  19. Miros2424 says:

    This IS the Winner !!! (nolo contendere)

  20. svofski says:

    Incredible! Consider adding a good resonant filter to make it complete :)

  21. Kristoph says:


    thats the sort of drum machine i’ve been wanting for a while

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s


Get every new post delivered to your Inbox.

Join 97,541 other followers