Mark IV Version A

[lee1836]

This Mark IV is being auctioned off at a place in Carefree, Arizona called the Ace of Estates. You can see it at https://www.invaluable.com/auction-lot/1990s-vintage-mesa-boogie-mark-iv-version-a-combo-9c643ffafb What is a Version A?

 

[16Bit]

There were 2 main versions of the Mark IV, called A and B. The main difference is the FX loop; if you look at pics of the backs of both amps you'll see what I'm talking about. Some people say that they sound slightly different too, but for the most part they are the same.

 

[sloanthebone]

https://mesaboogie.zendesk.com/hc/en-us/articles/221885367-Is-my-Mark-IV-an-A-or-B-model

 

[FedWar]

There were 2 main versions of the Mark IV, called A and B. The main difference is the FX loop; if you look at pics of the backs of both amps you'll see what I'm talking about. Some people say that they sound slightly different too, but for the most part they are the same.

Loop is not the only difference.
The lead channel in rev A is voiced as the iic+ circuit hence it is why it is more sought after.
You can clearly see this in the schematics around online.
I've had both a late rev b and an early rev A, and the latter is what I've kept. Sounds better I'm both feel and character.