In the next few posts I go back to what I like building the most – drum modules. This time I went for single voice drum modules and I wanted to check out circuits that utilize a single polarity power supply being that the boxes I used (wooden jewelery boxes the size of a cigar box) were too small to house a dual polarity power supply in them.
Granted, single polarity circuits that can be powered with 9-12 volts don’t sound quite as good as their dual supply counterparts, but they can be powered with a battery and they do give decent results.
The circuit of the Syntom II comes straight from an EM&M magazine published in April 1983. It’s an improved version of a circuit published in the same magazine sometime earlier that was simply called Syntom. The schematics and info for both can be easily found on the web so I’m skipping the technical information.
The circuit is pretty straight forward. A tunable VCO, a VCO sweep, and a noise source that runs through a sweepable VCF. The sweep is controlled with the Decay. There’s also an adjustable LFO spiting triggers for drum rolls. Interesting feature.
I don’t think the Syntom II makes much of a kick drum, but I like it as a snare, and of course it makes nice tom sounds, peeeeeooooow disco sounds etc.
Check it out in the video below. The drum is triggered with a MFB sequencer but can also be triggered with a drum pad.