Green Pony

The OD-820 was Maxon's answer to the popularity of the Klon Centaur.  While it's not a clone of the Centaur, it still employs the same dual-ganged drive knob concept that gives the Centaur its ability to go from a completely clean transparent boost to an overdrive and an internal charge pump that takes your standard 9 volt power supply and increases the voltage for extra headroom.  Where the two circuits really differ though is in the actual distortion circuit.  The OD-820 uses Maxon's (and Ibanez's) famous Tubescreamer circuit.  This is a huge advantage for DIY-ers since there are many well documented modifications for the Tubescreamer, and most of them apply to the OD-820.  Another place where the OD-820 circuit differs is in the way its dual-ganged drive knob works.  As you turn up the gain on the Centaur, it shunts clean signal to ground.  And as you turn down the gain on the Centaur, it shunts the overdrive signal to ground.  The Centaur sounds amazing with the gain knob mostly cl