OK: Is the Zendrive based off a Mosfet design, as the Mosferatu is? The Zen claims to have a very Dumble type overdrive. The Fulltone MOSFET Fulldrive Anniv. also claims to have a Dumble type tone when the Mosfet part of the pedal is engaged. Is the sound of a Mosfet a characteristic part of this Dumble overdrive tone? Is using a Mosfet just a convenient way to attain a tone very similar to the Dumble overdrive sound? I do not have any schematics of the mentioned products, and deleted my old fake DUmble ones, because I felt that they were very off, and I had nothing to base them on.