The Mark II-A has a very unique sound, especially, on the clean channel.
According to Mike Bendinelli, it is very much like a tweed Bassman and like the typical Jerry Garcia sound. He also said that you won't find the II-A sound in any other Mark series amp. Mike says it sounds better with single coil pickups.
I also recall that there was an interview to Randall Smith (you can find it in the Mesa Boogie site) where he was asked who came in first: himself with the Mark II-A or Dumble with his amp. He replied that both of them were working on similar designs with no knowledge of what the other one was doing.
In Randall Smith's own words... "As far as Dumble, I don't know much. I've never been inside of one of his amps, although I hear they're all gooped up to prevent copying and that they are built on printed circuit boards. I did run across a hand-drawn block diagram somewhere — I don't know — Gerald Weber's book or Aspen's — of an Overdrive Special and it looked to me like the functional equivalent of a Mark II. The configuration was the same, deriving the overdrive the same way, had the controls and internal switches in the same locations and so on. Howard no doubt has his own ways of doing things and makes great amps, so many of the parts values and such could be different, or the whole thing could be different for all I know. Really, my only exposure to his amps is that one block diagram, although I did meet him briefly in 1973 or'74."
