The PS-3100 is the smallest of the Korg polyphonic synthesizers. Korg's definition of "polyphonic" was that you weren't limited to just a certain number of "voices" as other conventional synthesizers are. So unlike an 8 voice Oberheim, the Korg PS-3100 could play all of its 48 keys simultaneously!
Although the sound generation capabilities of the PS-3100 are limited to only one oscillator and a filter with no resonance controls, it does have some things going for it that many other synths lacked. First, it has a special filter called the triple resonance filter in addition to the standard low-pass filter. This filter can create some very interesting sounds out of it and is especially good at creating phonetic (or vocal) sounds.
The next biggest thing going for this keyboard is that it is modular. Most of the various functions on the synth are patchable. At least one function is not (sample & hold frequency). This is where the power of this synth really comes in. Much in the way the Oberheim Xpander became so popular, the routing capabilities of this synth can make it do things that just aren't possible on standard synthesizers! So you can only imagine how monstrous a synth the PS-3300 is (basically three PS-3100's in a box)!
I have just recently finished installing a Kenton MIDI kit into this wonderful synth. It was not a fun task as the kit was really designed for the PS-3300. I will leave the gory details out here, but you can find the whole story on the E-Music DIY Archive soon.
Here is a front inside view of the PS-3100:
Here is a closeup of the Kenton analog board and
a custom board:
What a mess!
And finally, the rear view of the PS-3100:
Notice the Kenton MIDI board (fifth board from the left) peeking out.
The MIDI kit was not easy to install, so I do not recommend anyone doing this who does not have any electronic background. The kit originally called for adding a special box onto the back of the synth from which the MIDI cables would be plugged in and the analog signals could be patched from. Instead, I routed the various analog signals to existing patch points allowing all of the original features plus giving patchable MIDI control on top!
And finally, here's some humor. Note the spelling!
MG1 Schematic - Formatted for 300dpi printer (Poor quality.)