A well-known secret to great tone out of the vintage, 4 input Marshall™ amps is to use a patch cable to connect two of the inputs together. When this is done, the HIGH TREBLE and the NORMAL volumes are both active and can be blended together for the perfect crunchy combination.
That is what Marvel Drive recreates. Just like the amp, Marvel Drive uses two gain stages in parallel, one with a bright and throaty scream, and one with enough thump to rattle the walls.
Marvel Drive's circuit is 100% JFET based, with no clipping diodes or op-amps. JFETs are a special type of transistor that behaves very similarly to vacuum tubes. In fact, part of Marvel Drive's circuit is identical to that of a plexi amplifier, substituting JFETs for vacuum tubes. This gives Marvel Drive the touch sensitive and dynamic response of amplifier.