Sculpt-O-Sound presents: the AI202-O-Matic
The AI202-O-Matic is based on a General Midi sound module that was meant to be an add on for a PC sound card. It was manufactured by Korg and is based on AI2 synthesis. Back in the day when people started playing games on XT and AT clones of IBM PCs the sound of these machines was quite primitive. So some manufacturers started making upgrades. Oftentimes these were modules one could connect to an existing PC sound card, or at least to the ones fitted with a so called Waveblaster-port. This was present on most/all Soundblaster-cards and -clones. The module was meant to add good quality MIDI-controlled sound to games.
[Edit] As @handsomegenius notes below, this seems to be historically incorrect. The General Midi standard wasn’t created until the '90s and XT and AT machines were 80s machines. Yet another sign that my memory isn’t what it used to be …
This picture shows a KORG MBCS35104 with an AI202 chip on it I found in my stash of old pc interfaces the other day.
Interfacing this is quite easy and does not require any ancient pc hardware, as can be seen in the following schematic. It needs some power and a midi signal as input and the signal generated by the device can be taken from the left out and right out lines. C6 and R1 are there to generate a reset signal at power up, to ensure that the module is reset properly. I added a blue LED and a 4k7 resistor to pin 3 of IC2a which signal midi data coming into the device.
B.t.w. on my Korg PCB the numbering of the row of pins was printed wrong, so a check is a good idea.
So I added some connectors to a piece of perfboard and the rest of the components (contrary to what the partial build in the picture shows I ended up using a TIL111 for IC1 and a 4k7 resistor for R5).
Because of the layout I chose I could piggy back the perfboard on the sound module.
I added a 3D printed bracket, screwed the pcb to it and glued the bracket to the front panel which I cut with a K40 laser.
The Korg MBCS35104 was released in 1991, has a ROM size of 4 Mb containing general midi sounds and some drum kits. The patch set is called ‘Cleanwave’. The polyphony is 32 voices, so it is quite a powerful synth!
There were plenty of these devices made and they seem to be easily available via 2nd hand markets.