Used but in excellent shape !!
This is an altogether more sophisticated unit that, in Moog's words, "employs a Moog Ladder Filter, boutique FET amplifiers, and classic OTAs in its drive section”. It offers four controls — input gain, the cut‑off frequency of its resonant 24dB/octave Moog low‑pass ladder filter, tone (which is a multi‑mode LP/BR/HP filter), and output level, with switches to select between two humungous drive ranges (+6.8dB to +48dB, or +16dB to +57dB) and to add 15dB of resonance (or not) at the filter cut‑off frequency. While guitarists may view this as a sophisticated overdrive pedal with lots of tone control, synthesists will view it more accurately as a sophisticated filter pedal with lots of overdrive.
To my surprise, it proved to be one of my two favourite Minifoogers. Again, I tested it using the SH101, and to say that it added weight and power to the sound is an understatement; it was like playing the synth through the overdriven channel of a Hiwatt head and a pair of 4x12s (which, if you've never had the opportunity, is enormous fun) but with a different character and a wider range of sounds, from slightly overdriven to the distortion of doom. Somewhere between lay all manner of sounds that I recognised from my youth, all played on 'classic' synths such as Minimoogs and Odysseys (because there was nothing else available at the time) yet now pouring forth from my humble little SH101. As for sticking the MF Drive onto the output of a Korg Z1 to see what it might do to an early and sometimes slightly clinical virtual analogue synth… oooh!
Adding the expression pedal, then, did much more than turn the MF Drive into an expensive wah pedal. With the filter knob set to minimum and the pedal closed a muted, but nonetheless slightly driven, sound emerged. As I opened the pedal, the filter opened and the drive level also increased, which provided lots of opportunity for expression while playing widdly lead solos. Of course, the nature of the sound also depended upon the input gain, the tone and the peak settings, so there was plenty here to be discovered, ranging from a gentlemanly boost at the bottom end to huge, aggressive filter sweeps. Substituting the pedal with the output from the RS60 contour generator gave an indication of what the MF Drive is capable of adding within a modular setup, and directing its output to the input of yet another filter allowed me to control a further overdrive stage, just as a guitarist would use gain to overdrive the input of the aforementioned Hiwatt stack. Sticking a MIDI/CV converter between the Z1 and the Minifooger even allowed me to use velocity and aftertouch to control the tone on a note‑by‑note basis, with some wonderfully expressive results. Sure, it would have been nice to have some additional control over the band‑reject frequency and the Q of the filter, but that probably lies beyond the remit of a low‑cost pedal. I offer just one note of caution; because of the enormous gains on offer, you're going to need to place a noise gate after the MF Drive.