How to Load Your Own ZX Spectrum Cheetah SpecDrum Samples

It’s easy to take digital music production for granted these days, because computers are so powerful that it’s a trivial matter. Even your cell phone can produce high-quality synthetic sounds. But there was a time just a few decades ago when that wasn’t the case, and making electronic music was an expensive undertaking. One way to cut costs was to use add-on devices for computers, like the Cheetah SpecDrum drum sequencer device for the ZX Spectrum. Unfortunately, the available SpecDrum samples were somewhat limited. But Matt Harrison has figured out a way to load new samples.

The Cheetah SpecDrum was a drum sequencer device that could be connected to the ZX Spectrum. The hardware inside is pretty simple, and the only ICs (Integrated Circuits) used are a DAC chip, a quad op-amp, and a quad NOR gate chip. Like most other software and data for the ZX Spectrum, samples were stored on tapes. But only a few of those tapes were ever released, and so the sounds available were limited — and outdated now. Harrison wanted to be able to load up new samples so he could use the SpecDrums to create beats that were never possible before.

To do that, he first used the FUSE emulator to figure out how the sample data is stored. That turned out to be pretty unintuitive, but Harrison was eventually able to figure it out and import the existing samples. After determining the sample rate, he was able to create his own samples that were compatible with the SpecDrums. Finally, he was able to use a tool called ZX-Blockeditor to store those new samples as data that could be read by the ZX Spectrum. By doing that, he can use the SpecDrums software to load his custom sample kit and play those samples on the actual ZX Spectrum.