Early Mark Series: Mark III, Mark II, and Mark I
Mark I: 100W, 1-12" speaker, all tube chassis, dual channels, cascading gain, front black control panel, two inputs, six black knobs, wood covering, wicker cane grille. About 3000 were manufactured in the 1970s. Note that the Mark Ones weren't labelled as such until the Mark II came out.
Mark I Reissue: 100W, 1-12" Celestion Custom 90 speaker combo, all tube class A/B chassis, 4x 12AT7, power: 4x 6L6, two modes, reverb, front black control panel. two inputs, six black knobs, half power switch, effects loops, Imbuya hardwood or cream vinyl coverings wicker cane or brown cloth grille.
Mark II was similar to Mark I original but with added switches for preamp, five band equalizer. Some early models have a solid state device to replace preamp tubes. Internal switch between channels. Made from late 1970s to early 80s.
The Mark IIA featured footswitching channels and the Mark IIB has the patented Simul-Class power tube. The Mark IIC has an improved effects loop and quieter footswitching and the Mark III featured a three channel design.
