The Mark III was launched by Mesa/Boogie in 1985. It introduced a third channel, a "crunch" rhythm sound right in between the rhythm and lead channels. This amp has a dual footswitch system: one footswitch alternates between the current rhythm mode and the lead mode, and the other selects either the clean rhythm mode or the crunch rhythm mode. The two rhythm modes share all of their controls, while the lead mode only shares the rhythm modes' tone stack, featuring independent gain and master volume controls. The physical switch for the crunch rhythm mode was implemented as a push/pull switch above the Middle frequency control. Most Mark III's have presence and reverb on on the back (except for long chassis') unless not desired by the buyer; Graphic EQ was also optional all in either head or combo format. The Mark III went through multiple revisions, similar to the Mark II. Each revision had a slightly different voicing, but identical functionality. Non-Simulclass versions of the Mark III came in either 60w RMS with two 6L6's or 60w/100w with four 6L6's in the power section. All Mark III's contain five 12AX7 tubes in the pre-amp section, including reverb as well. Simul-class Mark III's usually contain two 6L6's in the inner sockets and two EL34's in the outer sockets for 15w/75w use. This amp is well used, and has wear and tear on the exterior. It has been re valved and re potted, and also comes with a flight case.
