This is a custom Paia Fatman that I built several years ago. The basic Fatman kit is actually still being sold today. Of course, one of the neat things about building a kit is all the learning you do in the process, plus you can make mods. Check out the Paia web page for ideas. Below are some photos of the front and the rear panel which has the requisite MIDI in and out jacks and of course an audio output. Power is supplied by an external transformer. I added a couple inputs for an external VCF mix input and modulation so I can link it to my modular synth. Also shown is a picture of the inside of the Fatman. My unit has lots of mods, including an ASR LFO, subharmonic generator, PLL VCO, ASR/ADSR reverser, and pitch LFO. Paia’s design is based around an 8031 microprocessor, but I used an Intel 8051 which has an 8K byte by 8 bit EEPROM built in so the external memory and decoder is not required – that’s why there are two empty sockets on the PC board. The Fatman is a normalized synth, which means the connections aren’t changeable. The MIDI interface controls the VCOs, which feed to the VCF and then to the VCA. Of course the knobs still allow for major tweaking of the sounds.