Marshall JMP 1987 50w Lead Head 1973, Black

Built in October of 1973, this is one of the first circuit-board Marshalls following the transition away from hand-wired assembly. It features the long-style headshell, designed to sit neatly in the indentations on top of 4x12 cabinets. A cool detail on this one: certain amps exported to the U.S. were outfitted with Unicord OT50M output transformers. Supposedly, Unicord wasn’t confident the Drakes would hold up under heavy use and chose to supply their own for the U.S. market. Legend has it Drake later copied Unicord’s design for their transformers, though that remains unconfirmed. 

The amp has moderate signs of wear, with some light burns on the top, indicative of long term gigging. On the back it has a name written in white paint pen, along with a drawn band logo.

Internally, the filter caps have been replaced, along with the screen-grid resistors, bias resistors, and power-tube sockets. A couple of orange caps were added to the input jack, though they don’t seem to affect the sound. There are also some interesting value choices in the phase inverter section, but they resemble parts Marshall was known to use around that time—please refer to the circuit photos for further details.

Overall, this is a fabulous-sounding amp with that signature Marshall crunch we all know and love.