Mark III Stripe/Dot History
In March of 1985, the Mark III introduced the world to three footswitchable voices in one amplifier and took its position as the flagship of the line, the next step in the evolution of the Mark Series Family of amps. The Mark III, like the Mark II had a few different versions over the period it was in production but rather than indicate the changes as an A, B, C or C+ model, the chassis was marked with a stripe or dot of different colored markers above where the power cable meets the chassis to indicate the revision.
As with all things MESA, what these various stages represent are a matter of opinion with respect of the sound character. They represent snapshots in time of the development of an amplifier line. If the amplifier gets you the tone you want, the jiffy marker is nothing more than a mark of its vintage.
The order of these versions and what one can expect to notice from version to version is as follows:
No mark, little black dot, black marks or "x" 's: Early Mark III
• These are lean and powerful amps with more output power than a Mark IIC+
Purple: reshaping of Rhythm 2
• Rhythm 2 was shaped to be more "rounded", have less gain, with improved level
Red: Rhythm 2 & Lead Mode Tweaked
• Rhythm 2 was further developed and is very hot. Lead mode was also tweaked to close in on the Mark IIC+ sound
Blue: Reshaping of Rhythm 1
• Reshaping of Rhythm 1, more aggressive preamp gain, Power section made akin to IIC+
Green/Simul-Class: Final Rhythm 1 & Lead Channel reshaping
• Cleaner Rhythm 1 & Lead channel reshaping - Unlike other Simul-Class amps, these Mark III's were wired in Pentode (not triode) in the Class A sockets for more power. Power section is same as Blue Stripe/Dot otherwise