The Poly 800 "Polybeast"

A few years ago, I bought a Poly 800 for something like 3500 yen ($35USD). It was my first real synthesizer, and as cheesy as it sounded and as limited as its controls were, it was my gateway drug to the world of synth addiction. It was light (at least for an 80`s machine), ran on batteries, and the joystick was super fun. I got tired of having to control all the parameters using the button system tho.

Then one day during a google dive I stumbled on the "Moog Slayer" mod, and couldn`t wait to try it out. Physical controls for filter cutoff and resonance! My soldering skills were reasonable enough that it survived the surgery, and came out a new machine. However, I ended up buying a lot more synths not long after that and I stopped using it so much, so I flipped it on eBay.

Then, earlier this year, I stumbled on circuitbenders.com`s Poly800 page. They had managed to really push the limits of those mods! Not only did they have filter controls (including a slope selector switch), but auxiliary inputs, an input selector for the "FM" control and CV controls for the filter!

I was keen to dive back in and try my hand at modding another one, to see what I could squeeze out of it. Unfortunately, in the two years since I bought my first one, they had gone up quite a bit in price!

And here is the result!