Most amp enthusiasts know the story: Jim Marshall ran a London music store in an era (the early 1960's) when demand for Fender amps far outstripped supply, and, in an effort to copy the Bassman, inadvertently invented the sound of hard rock, and the look of the amp stack. While Marshall collectors can spend a lifetime tracking down the hundreds of species, the cornerstone pieces are; The JTM45 head; The "Small box" 50w; the 100w Super Bass/ Super Lead "Plexis". Legendary (and scarce) combos include "The Bluesbreaker" and "The 18-watt". Marshall's early "Glory Days" came to a gradual close around 1973, with the advent of printed circuit boards. Among British rock amps, Marshalls are, arguably, the easiest to live with, in terms of voltage compatibility, ease of repair, and ready availability of parts, tubes, and knowledgeable technicians.