Mesa Boogie MK II A, with Graphic EQ (April 1980) Ivory. Speaker Eminence alnico square magnet 12'' (original for this series). Fully retubed with brand new TAD (Tube Amp Doctor) tubes.
+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.