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Technical Info/Knowledge Hub
Everything on the workbench: how to date a Marshall, speaker wiring, model-specific repair guides, and circuit deep dives.
Marshall Amps
Marshall and Celestion Date Codes
No fluff, just the date code charts.
Marshall Amp Identification 1967–1980 — The JMP Era
Cosmetic and construction changes through the JMP era, year by year.
The Ultimate Split Channel JCM800 Guide!
Detailed fixes for the known channel bleed issue and oscillation problems at high gain settings
The Ultimate JCM900 SL-X Guide!
Everything you need to know about Marshall's high-gain SL-X circuit, mods, and maintenance.
Oddball Late 70's Super Bass Circuit Info
Notes and schematics for the unusual late-1970s Super Bass circuit variations.
Mid 70's Super Bass Circuit Info and Schematics
Highlights changes made in early to mid '70s Super Bass amps.