SN 160650 via
this auction
"The Original, and still champion, Vocoder from Korg. [It's not the original vocoder, but it IS the original Korg vocoder] I feel it's far superior to the vocoder features in the newer units. [I own an MS2000R and the vocoder in it does not hold a candle to this] This is probably due to it being made EXCLUSIVELY to be a vocoder. This has both Microphone and carrier signal inputs to allow use as a processor. It's a gas to run a drum machine through it to create VERY unique timbres. The built-in carrier signal features an "ensemble" effect which is somewhat like a chorus effect - not unlike the chorus effect on some older roland gear. You can mix the carrier signal with a built-in noise generator for more varied effect as this enhances any sibilance present on the mic input.

The top panel mic input is for a proprietary Korg mic which I never owned. I have heard that they were kind of crap anyway and the only advantage is that they attach directly to the top panel. Any mic with a 1/4 plug can be input to the front panel mic jack, and this is how I have always used it. If you are using a more exotic mic, or something that requires phantom power you will have to figure out how to do so. I always used a simple Beyer dynamic.
NOTE: The interface standard is the old and somewhat odd Korg Hz/V system, wherein the frequency is proportional to the control voltage [not the more common 1V/octave as on MOST older synthesizers and virtually all new modulars]. It is possible to adapt a "standard" 1v/Oct to communicate with this, but it's not perfect and prone to inaccuracy at the extreme ends of the range. This WILL interface with other old Korg gear [MS-10/MS-20/MS-50/SQ-10/etc] with no trouble at all [I have connected my MS-10 and it works perfectly].