1966 - TheJTM45 changed to JTM50 on panels: Block logos now changed to white script with gold coloured plating: Valves changed to EL34's and Gz34 rectifier phased out: Transformer uprated. 100 Watt production was now standardised with a single 100 Watt transformer and EL34 output valves. The 1961 and 1962 were upgraded in line with the heads and cabinets slimmed down. All cabinets now had corner locked joints. As a method of quality control all cabinets were signed inside. 1967 - Chassis were all upgraded from aluminium to steel construction. The first 200 Watt Majors appeared, with just treble, bass and volume controls, "active" tone circuitry and KT 88 valves. 10 and 18 Watt combos introduced in 1x12, 2x10, 2x12 tremolo or non tremolo versions. Fret cloth on cabinets changed to basket weave in late '67. 1968 - The Major was modified to match the normal panel layout and active electronics dropped. Gold logos changed to white. 1969 - New gold metal panels were introduced across all ranges. Serial numbers now followed a dating system with the letter A appearing after the number. By 1970 cabinets had all changed to check fret cloth. From this point onwards, Marshall amplifier history is much more easily accessible from the serial number and the inspection tag attached to every amp chassis. Notable dates after 1970 are as follows: 1970 - The period of coloured Marshalls. Orange, purple, blue etc. 1974 - The first transistor 100 Watt amp (model 2098) was introduced. 1975 - Design of the first Master Volume amp was completed. 1976 - All units changed to thicker wood finish and large white script logos. Black fret cloth gradually introduced. 1981 - JCM 800 range launched. 1982 - The first split channel amps arrived. 1987 - 25/50 silver Jubilee units produced. 1989 - Series 9000 rack systems released. 1990 - The year of JCM900. 1991 - Valvestate swept the world. 1992 - The 30th Anniversary. With each passing year more Marshall amplifiers achieve "classic" status. The Anniversary Series Limited Edition amplifier is such a fine piece of engineering and technology, that it will achieve this status instantly. One thing is certain, whichever Marshall you own it has a unique pedigree and at some time will command its own place among the Marshall classics.