After the preceding looks of the early 50's (TV front from 1950 to 51/2; wide panel '52–54), Leo Fender changed the cabinet design again, this time opting for no extra wood on the front of the amp, except for the narrow top and bottom panels that hold the baffle board to the cabinet.
The early models of the larger "narrow-panel" tweeds are also remarkable for their refined electronics whose circuit design incorporated dual 5U4 rectifiers in the Twin and Bassman models, another improvement given Fender's quest for a louder, cleaner amplifier.
I wish I could say that I figured all this out on my own.
While doing research on Fender amps in general, and the Champ in particular, I came across the most amazing series of articles by Greg Gagliano on the subject. If you have any interest in vintage Fender tube amps, without question you’ve got to read them all.
Five watts and the simple toneful circuit allowed the Champ to be used easily and often in recording studios. Front" style cabinet; the 800 was covered in greenish fabric while the 600 featured two-tone blonde and brown vinyl covering. Besides, no article in the Dating Fender Amps by Serial Number series would be complete without some interesting information, n’est ce pas? I promise the tables will still be there after you finish reading.In a BF Vibrolux Reverbs you could have either Jensen, CTS or Oxford, the BF Super Reverbs had Jensen, CTS, Oxford or sometimes JBL, the BF Pro Reverb had Jensen, Oxford or Utah, .In the silverface era Eminence, Oxford, Utah and Rola were more often used and Jensen was phased out.(with 8" speaker), changing a year later to "Champion 600" (6" speaker) with circuit designation 5B1. This style lasted until 1953, when Fender's cabinet style changed to the "Wide Panel" design with a tweed cloth covering.