To my knowledge, this is a factory made head, and not a conversion, which appears to be very rare. I can't confirm if that's true or not. It works perfectly, and the gain channel is great. This is very close in sound to a Mark Series, and will get you that early Metallica sound. This model was also used by Kurt Cobain.
I included a gut shot, which is incredibly clean for a 1985 Mesa. All the caps have been changed as well. Look up some pics on the web, and you will see that this is pristine in comparison to the normal wear and tear.
Honest seller, with extensive knowledge of the equipment I am selling.
I am looking to trade for other Mesa amps that can do modern metal a little better, mainly a Mark Series, Badlander, or other brands like Soldano, Friedman, et...