I had read (and looked at a lot of amps) that it was 1976-1979, maybe early '80 or 81, I cant remember. But I have not been able to validate any amps prior to 1976 that were 1959 JMP's that had rocker switches. If you have evidence that will back up the 1974 date I am all for it. I am pretty sure that Randy had 2 stacks made for him when he went to England. One in white and the other in standard black and that was in '79.Nick Hughes wrote:My conclusion was based off topics in rhoads tk
Then what year are his amps ?
His amps had rocker switches on them and they were JMPs
JMPs only had rocker switches from 1974-1979
Think the rocker switch came to be in 1974 but I am not sure it was used on all models and I am not even sure that is the right date. Any one have some credible info on this? Mine just comes from the years of Ebay looking and working at Guitar center so it is more anecdotal.
Just found this
http://www.solodallas.com/the-vintage-marshall-guide/
it claims 1976-1981. Scroll done to the "The “Rocker Switch” JMP era: 1976 – 1981" part.