A major component of each Moogerfooger is its input drive stage, which is able to add warmth, distortion, and crunch to a sound. The MF-109S Saturator is able to move from tight, dynamic overdrive and analog saturation to smooth compression and expansion by pairing a wide-range envelope follower with bipolar control over the unique drive circuit of the Moogerfooger Effects Plug-ins. Further, it models the noise generator circuit of the Minimoog Model D and allows for control of both noise generator level and noise tone with switchable filter type. The MF-109S Saturator's envelope follower and noise CV outputs and multiple CV inputs allow it to speak with all of the other Moogerfooger Effects Plug-ins.

The MF-109S is an AUv3 effects plug-in that requires a compatible host or DAW to function.