For sale is a 1981 Marshall JMP 2203 MK2 100-Watt Tube Head. This amp sounds great. It is in very good condition but does have some minor wear. The amp has had some mods but is all original otherwise(with the exception of the tubes). The mods are listed below. The tubes still have plenty of life.

Dave Friedman installed Tube Buffered FX Loop
Dave Friedman installed improved Master Volume
Dave Friemdan increased gain slightly

Jeremy from Ground Zero:
Adjusted negative feedback
Added Depth mod (knob on back)
Added SAT knob (also on back, rolls in a Zener diode -- increases gain, compression, and saturation)