Marshall Plexi "Small Box" 50W Head (1968, Model 1986)
 
This amplifier is a 1968 Marshall Plexi 50-watt "small box" head, model 1986, identical to the type famously used by legends such as Jimmy Page, Jimi Hendrix, Duane Allman, and Paul Kossoff. Bearing the serial number 10696, this unit dates from late 1967 or early 1968—a period considered by many collectors and musicians to be the golden age of Marshall amplification.
 
Although a master volume circuit was added at some point in its history—leaving extra holes on the rear panel—it was later removed to restore the amp to its original design. The front logo is a reproduction, but all the transformers remain original, which is crucial for maintaining the authentic tone that has made this model so revered.
 
Interestingly, this particular amplifier also carries a piece of rock history: it once belonged to the Belgian heavy metal band ACID, active from 1980 to 1985, which explains the stencil marking on the underside.
 
A Brief History of the Marshall Plexi
The nickname "Plexi" comes from the Plexiglas (acrylic) front panels used on Marshall amplifiers produced between 1965 and 1969. The 50W “small box” heads, like this one, offered a more compact alternative to the larger 100W stacks, while still delivering the unmistakable Marshall roar. These amps became an industry standard for rock and blues guitarists thanks to their warm yet aggressive overdrive, tight low-end response, and sparkling highs.
 
The model 1986 was originally marketed as a bass amplifier, but many guitarists quickly adopted it because of its unique tonal characteristics. Compared to the model 1987 (the “Lead” version), the 1986 circuit had slightly different component values, giving it a rounder, thicker sound that paired especially well with humbucking pickups and vintage-style cabinets.
 
Legendary Players
This exact model is linked to some of rock’s most influential figures:
Jimmy Page (Led Zeppelin) often relied on Marshall Plexis during Zeppelin’s early tours, shaping the thunderous tones of songs like Whole Lotta Love.
Jimi Hendrix used 50W and 100W Plexis extensively, pushing them to their limits for his groundbreaking live performances, including Woodstock in 1969.
Duane Allman (The Allman Brothers Band) favored Marshalls for his soulful slide playing, blending the amp’s natural overdrive with his signature Gibson Les Paul.
Paul Kossoff (Free) created one of the most recognizable classic rock tones—thick, singing sustain—by cranking his Marshall Plexi through vintage speaker cabinets.
 
Each of these players demonstrated how versatile the Plexi could be: from shimmering cleans at lower volumes to explosive crunch when dimed.
 
Specification :
Model : 1986
Production year : late 1967 to 1968
Output : 50W
Transformers : original
Size : small box