BJF (The designer behind the Mad Professor stuff spoke about his LGW (Little Green Wonder) pedal over on the freestompboxes forum. A schematic was provided:
As Bjorn pointed out there was a 1M resistor missing from the gate of the input buffers FET but I have now fixed that on the above schematic.
Here are a few quotes from BJF on the magnificent Little Green Wonder:
"LGW was made for those that really not could get along with standards
and the idea of it came to me in a request of what a BJF TS style would sound like and the guy told me he'd run a fuzz into TS's to smooth things....and so I wonder why would anyone do that as it would bring funny little artifacts ontop of sound aswell as cut all the lowmids and bass-oh yes I got this tested and listened and understood but still, and you know if headroom was higher this could be avoided and the basic filtering to the treble and then you could also use it with humbuckers and P-90's......."
"The first BJF LGW's were supplied with LF 353 which makes for higher headroom, but many wanted an alternative that would work at lower voltages and that would distort easierly thus TLC272 and for a time both chips were supplied but it caused problems so eventually only TLC 272 and a chip can be bought allover the world without problems."
Note the very unusual tone control that consists of a dual 20k pot! And the green LEDs used for clipping. Not your standard Tubescreamer type overdrive by a long way :-)
Many thanks to all at freestompboxes, and especially Bjorn of BJF for being so forthcoming and helpful about his design!
Check out the Little Green Wonder in operation;
Here are some layout files I was sent, I'm unaware who's they are;