Marshall JMP 1959 Super Lead 100w Plexi Panel 1969, White

This wonderful amp is from the first half of 1969, when Marshall still used 5-digit, non-sequential serial numbers. The white covering is an extremely rare color, with only a handful of these amps in existence. Despite the typical wear these amps endure, this one has held up remarkably well, showing only moderate signs of previous use and minimal tolex blemishes.The inside isn’t completely undisturbed, but has kept things correct where it counts, with the original transformers, coupling caps, and most of the resistors intact. Here is a list of changes made, and please refer to the circuit pictures for further details:

• Bulgin port removed, replaced with an IEC 120V port
• All electrolytic caps replaced
• B+ diodes changed, along with some wiring in the power section, including filaments
• Tube sockets replaced—newer sockets in the power section, preamp sockets are likely from the late '70s
• Input jacks replaced
• Pot on the Normal Channel replaced with an Alpha pot; period-correct pot used for the Bright Channel
• Solder joints disturbed on the preamp, but it still retains period-correct WIMA/Mustard caps and Lemco silver mica caps
• Four resistors swapped for modern carbon film equivalents; the rest are period-correct
• Lemco .68µF large red cathode caps were likely added later but are still era-appropriate
• One knob replaced

Overall, this translates into a beast of a 100w Plexi amp. With fresh filter caps and tube sockets, this amp is ready for another 50 years of serious use!