Each generation has an instrument that defines its sound, and for those whose formative music years are in the 1980s, a strong contender for the crown is the Roland TR-808 percussion synthesizer. Its soundtrack may have been recognized throughout that era and several hits from each decade, and although the original instrument was not a commercial success, it remains accessible through sample packs, emulation, and clones. The 808 is an all-analog device that did not use the sample, thus [Mark Longstaff-Tyrrell] Has been able to reproduce its distinctive cobble sound with some references to the original circuitry.
It is not too surprising to find that the circuit is freshly simple. The trigger pulse is converted into an envelope that controls a pair of oscillators. The mixed output goes through a bandpass filter to create distinct sounds at the output that you can hear in the video below the break. The circuit is recreated on a breadboard with the only exception to modernity is a microcontroller that replaces the original Smit trigger oscillators.
All in all, it provides an interesting insight into the synthesis behind a classic sound and gives us an enhanced appreciation for the design skills of those Roland engineers who created it. We’ve seen it a few times before the 808, with an explanation of the famous faulty transistors that contributed to its sound.
Header image: Brandon Daniel Derivative work: Clusternote, CC BY-SA 2.0.