 Mesa ultimately ended the Mark III's production since it overlapped with production of its successor, the Mark IV, which was introduced in 1990.Mark IIIs were still in steady production around 1994, and finally ceased as late as 1997, 11 years after their launch.The Mark IV was launched by Mesa/Boogie in 1990 as a three-channel amp - with independent controls for all three channels, except bass and mid, which are the same for both Rhythm 1 (clean) and Rhythm 2 (crunch).