Mesa Boogie MK II A, with Graphic Eq 1980 - Ivory

Mesa Boogie MK II A, with Graphic EQ (April 1980) Ivory. Speaker Eminence alnico square magnet 12'' (original for this series).
+Footswitch

The Mark II introduced channel footswitching. It was not referred to as the "Mark IIA" until the Mark IIB was issued. It was also available as a head (a standalone amplifier), which could be hooked up to a number of different speaker combinations, although a 1x12" cabinet was the most common. The preamp gain on the Mark IIs occurs after the tone controls and so, according to Mesa/Boogie, the IIA has a "tighter, more focused sound" than the Mark I.

The Mark IIA's control panel was extended from the Mark I's to include a separate master volume control for the lead mode, and various push/pull switches including Pull Bright, Pull Treble Shift, Pull Gain Boost, a separate Pull Bright for the lead mode, and of course, Pull Lead. The 1/4" jack previously marked "1" was changed to just "Input," and "2" was changed to "Foot Switch." The Mark IIA was a great improvement over the Mark I.