Punch Tape Musical Synth


[Jeri Ellsworth] sent over a 555 design contest entry that struck her as particularly interesting. The Synthanola is a three-channel music synthesizer that accepts input from an old Heathkit paper tape reader. While this hack might seem overly retro, it’s actually an extremely appropriate use of technology, as the Heathkit H-10 and the 555 timer were both popular tech in the 70’s. This retro-focused synth uses fourteen 555 timers, twelve of which are dedicated to synthesizing audio. If this entry does not win the contest, it certainly must be a strong contender for most 555 timers used.

[Thrashbarg] gives a detailed explanation of the logic used to drive the music playback from the punch tape, as well as full circuit diagrams for his entry. So far he has encoded MP3s of Bach’s Invention and Fugue in D Minor to tape, with hopefully more to come. In order to truly appreciate his efforts, the Synthanola should be seen as well as heard. Stick around for a pair of videos of the synth in action.

If you’re interested in seeing more 555 contest entries, be sure to check out some of our previously featured projects.



26 thoughts on “Punch Tape Musical Synth

  1. Very cool! I was in the USAF and used a punch tape system to reprogram aircraft processors in the 80’s, and this brought back memories… Plus I like Heathkits & 555’s, so it wins all around!

    Maybe someone will get inspired to set the WAYBAC machine to the 60’s and make a punch card version ;)

  2. Paper tape yeah! Now I am brainstorming how to do this pneumatically for a street organ type of thing, sorry no dwino or even electricity used. Lookup logic in a integrated vacuum matrix of leather pouches and valves, sounds doable.

  3. Punch tape!? I wrote my first program on TTY and saved it on punch tape, serious nostalgia. Amazing project. Bach is the natural choice, I got this flash back to Moogs, and ‘Hooked on Bach’.

  4. Punch tape!? We wrote our BASIC on clay tablets with sharpened reeds. If you weren’t careful in drying them in the sun or dropped your deck carrying your program to the high priests in the computer temple, you’d have to start over. And if your program didn’t compile you had to go to the back of the queue after debugging it. If you didn’t submit a working program to the high priest before the end of the lunar cycle your barley ration was cut in half!

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