The Warped Plexi is based on the three-knob version of Wampler’s Plexi Drive ™. Not only one of the Pedals that made the Brian Wampler pedal brand famous, but it also is one of the best sounding Marshall ™ in a Box pedal out there. I think there is no need to keep talking about the very British-sounding tonal options of this Overdrive. There are plenty of awesome demos about it on Youtube.
For this design we decided to keep it loyal to the original Plexi by Wampler, we just added another bass boost option for the toggle, having the stock version, stock bass boost, and the third position with a 220n to give you a deeper boost on the bass frequencies.
Just wanted to mention, that the tone potentiometer is quite powerful, so don’t get fooled by the fact that it’s just the three Knob version. This PCB does not require many parts, which makes it either a quick and rewarding build or a nice entrance in the world of building DIY Stomp boxes.
One thing to keep in mind. J201 getting harder and harder to the source. Use a trusted shop to get them. In all our projects we always give you the option to choose in between the standard transistor package or the SMD version, which we strongly recommend to go for, it has shown to be much reliable in terms of quality and availability. One final recommendation is to watch the size of the 470uf electrolytic capacitor when you’re sourcing the parts by yourself. They can be really tall what requires some creativity to make them fit in a small enclosure
- Bass boost toggle
For further analysis on this circuit take a look at this thread on Free Stomp Boxes Forum.