The 4-Track Cassette Drum Machine
By James Grahame
Mike Walters writes, "Here's my new instrument, The Drumssette. It's a programmable drum machine built out of a Tascam four track recorder!"
Mike has a history of creating amazing one-off instruments like the Melloman, a tape-based sample playback keyboard that uses the innards of 13 gutted Walkmen to play tuned vintage Mellotron keyboard samples. His latest electromechanical masterpiece is the Drumssette.
He says, "The sounds of the drums come right off the prerecorded cassette tape, and those sounds also clock the sixteen step sequencer inside. As the cassette plays, rhythms can be mapped out on the switch interface. This is how it works...
Each of the four tracks on the cassette tape contain a single, repeating drum sound. Track one has high hat, track two cymbal, bass drum on track three, and the last track has snare. These drums are synchronized with each other, and each track is isolated from the next.
There's a four position rotary switch on the front panel of the Drumssette. This switch routes a parallel audio signal (this doesn't go to the output) from one of the four tracks through the Tascam's headphone amp circuit, through a delay stage, another amplifier, and finally to the clock input of the 16 step sequencer. The selected audio signal determines the frequency of the sequencer, and causes it to step.
As the sequencer steps, each output is sent to a bank of AND gates. On the front panel of the Drumssette are 64 push on/push off (mechanical) switches in four rows of sixteen. These are wired with a common connection to the 9v supply bus, with individual outputs going to the other inputs of the AND gates. There are 64 AND gates total. If a switch is on, AND the sequence step is on, the output of the gate is 1. This will momentarily unmute that track's audio to the output, through a "Wired-OR" configuration using diodes."
Thanks to the combination of analog and digital circuitry, the Drumssette has a unique sound and a few endearing quirks. It can also be used to rhythmically gate audio from an external source like an iPod or computer. I can't wait to see what Mike comes up with next.