DIY Mellotron Made From 14 Walkmans

Mike Walters of Mystery Circuits makes unusual custom electronic instruments. Many are made from modified toys or other items, though he did also create a fabulous mod for the Moog Source which replaced all the troublesome membrane switches with a custom control panel.

Anyhow, one of his projects was a Mellotron like instrument (Melloman) which was constructed using 15 Walkmans playing voice tapes. Since then Mike has been comission to buikld another custom Melloman for Justin Vernon (of Bon Iver).

Mike took this opportunity to upgrade the Melloman to include individual tape speed control of the 14 Walkmans inside (Memorex players). Each of the players contains two notes one, octave apart, the sounds loop an on the original Melotron, with a little red light on the front panle to  indicate when this is about to happen.

Mike goes on to write:

There is a drum track on the 14th Walkman, like on the original Melloman. I provided two drum tapes for Justin. One was the disco preset on the Wilgamat, the other was a simple beat I programmed on the Trommemaskine. When the drum tape is rolling, and the drum switch is in the On position, drum beats are routed to the output. I added a groovy little LED to flash in time with the drums. When the blue and red arcade button is pressed, the beat momentarily switches to fill. This is also done optically like the notes, but instead of grounding the signal, the two opto-couplers A/B the left and right tracks. Left channel is the main drum beat, the right channel is the drum fill synched up with the main beat (like the notes, these signals aren't stereo, they're mixed to mono). What's cool is that the photo-resistors retain some energy, so you hear trails of the fill in after you let go of the button. That's what I was avoiding on the note tapes, but I used it as a feature on the drum tape.

Tempo is controllable via a speed potentiometer on the panel. It's wired the same way as the tuning pots, but has a wider range.

Other panel controls include main volume, tone control, and drum volume. There's a switch that changes the output from internal speakers to main 1/4", with a separate volume control for internal speakers.

To make room for all the tape players, and to get rid of redundant features like AM/FM radio and alarm clock, I had to remove the doors that keep the tapes in position. I also did that on the original Melloman, but I was able to use rubber bands. Rubber bands don't look so nice, and that solution didn't really work on this machine, so I had to do something different. The solution was to use Yamaha key-springs (thanks for the idea and the key-springs, Russ). I cut the springs in half, carefully bent them by hand, covered them in heat shrink tubing, then glued a rubber thread cap to the tops. The solution works, but it is kind of a pain to remove the tapes.

It truly is a thing of beauty - Justin is a lucky man.

Thanks to Failed Muso for the story

More Information

• MysteryCircuits.com