Ken Shirriff Breaks Open the Yamaha DX7

For better or worse, this synthesizer was king in the 1980s music scene. Sure, there had been synthesizers before, but none acheived the sudden popularity of Yamaha’s DX7. “Take on Me?” “Highway to the Dangerzone”?  That harmonica solo in “What’s Love Got to Do With It?”  All DX7. This synth was everywhere in pop music at the time, and now we can all get some insight from taking a look at this de-capped chip from [Ken Shirriff].

To be clear, by “look” that’s exactly what we mean in this case, as [Ken] is reverse-engineering the YM21280 — the waveform generator of the DX7 — from photos. He took around 100 photos of the de-capped chip with a microscope, composited them, and then analyzed them painstakingly. The detail in his report is remarkable as he is able to show individual logic gates thanks to his powerful microscope. From there he can show exactly how the chip works down to each individual adder and array of memory.

[Ken]’s hope is that this work improves the understanding of the Yamaha DX7 chips enough to build more accurate emulators. Yamaha stopped producing the synthesizer in 1989 but its ubiquity makes it a popular, if niche, platform for music even today. Of course you don’t need a synthesizer to make excellent music. The next pop culture trend, grunge, essentially was a rebellion to the 80s explosion of synths and neon colors and we’ve seen some unique ways of exploring this era of music as well.

Thanks to [Folkert] for the tip!