In 1954 the Champion 600 designation was dropped and the control-plate logo changed to Champ-Amp. Possibly these first Champ-Amps would have had the 5C1 circuits.

Then in 1955 the amp's controls were moved to the top, reflecting a chassis change, and the circuitry modified quite a bit. By 1955 Fender started putting its amps in the "Narrow Panel" tweed
cabinet. This was the model 5E1, capable of putting out six watts, still with a 6 inch speaker.