The Drumssette: drum machine made from an old 4-track
The Drumssette is a programmable drum machine built by musician and circuit bender Mike Walters.
A very creative DIY use of an old four track recorder, it was built using the innards of a Tascam MF-P01. The drum sounds are played off a prerecorded tape loop, with each of the four tracks containing a single, 16th note repeated drum sound.
The sounds on the tape automatically clock the tape loop inside, and they can be gated with the 16 step buttons for each track. This all adds up to a pretty funky tape-based, four track drum machine.
Track one contains a high hat, track two cymbal, bass drum on track three, and the last track has snare.
Any of the four tracks can be used to clock the sequencer, with a variable delay circuit. The delay circuit helps adjust the gates so that the attack portion is not cut out of the output. Here’s the technical explanation:
Since the trigger for the sequencer clock is audio used in parallel with the actual sounds of the instrument, the triggered audio from each track might lose a bit of its attack when it gets to the output, especially if the sound has a slower attack. To solve this, I built a delay stage before the parallel audio gets to the sequencer. This audio does not go to the output of the Drumssette. Using a PT2399 digital delay chip, the parallel audio signal is treated with a simple, adjustable delay, with no feedback (repeat stages) and a clean output. Delaying the audio signal before it becomes the clock signal allows the the operator to apply an adjustable delay parameter to the sequencer, which allows the gating to scoot over and focus on the next drum sound on the tape before the loss of attack. This happens because the audio on the cassette is time constant, and the delayed signal is variable. The momentary unmuting (gating) is dictated by the delay signal. You can also focus between sounds, to create double time beats.
There is also a “fill” function, which triggers all four drum sounds at the same time, giving a wonderfully lo-tech drum fill.
The case was built using an old case for a a Beckman analog pH Meter with a giant needle that Mike found on eBay for $10. The tapes were created on a computer instead of the four track, as the Tascam doesn’t allow multi-tracking. Earlier I did use the term “tape loop”, but it’s not really quite so – the sounds themselves are looped on 90min tapes…. for 90 min! The tapes themselves are not actually tape loops.
Here’s a video showing the basic functionality:
And gating a Moog PolyMoog:
Tape running backwards:
Mike begun work on the Drumssette in October 2009, and got it finished up a couple of months ago. He’s still got a wish-list of things to add to it, but it’s definitely an innovative use for an old cassette four track. Plus, it’s definitely got gobs of campy factor.