The Fender Blues Junior is most similar to the Fender Blues Deluxe, which adds a "drive" channel, an effects loop, and uses 6L6GC output tubes for 40 watts of rated output.Like many Fender amplifiers (particularly in the Hot Rod series), many limited edition versions of the Blues Junior have been manufactured since its introduction in 1995.The codes can be handwritten, which can occasionally make the letters hard to decipher. There is no reliable way to date 2003–2005 amps other than to ask Fender customer support to look up the date from the serial number.
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.
The process that went into figuring all of this stuff out over 6 years and countless owners of vintage Fender amps is hands down an amazing story.
The standard Blues Junior is dressed like a traditional black Fender amplifier, with black Tolex upholstery and a silver cloth speaker grille.
Although they differ in their external visual aesthetic, all variants of the Blues Junior for a given year are produced with the same electronics, apart from the speaker/driver.
Fender frequently releases limited editions of the Blues Junior.
All have the same electronic components and specifications but have cosmetic changes and often a different speaker, at varying prices.
“Dating Fender Amps by Serial Number, Part III,” 20th Century Guitar Magazine, Gagliano, G., March 1999, pp 122 – 127.
“Dating Fender Amps by Serial Number, Part IV,” 20th Century Guitar Magazine, Gagliano, G., March 2001. *”Dating Fender Amps by Serial Number, Part V,” 20th Century Guitar Magazine, Gagliano, G., January 2002. (This is where the partial chart above came from) “Dating Fender Amps by Serial Number, Part VI” Vintage Guitar Magazine, Gagliano, G., April 2010.
Lacquered Tweed editions, as the name implies, feature a cabinet upholstered with a lacquered tweed fabric.
Some of these have been artificially aged from the factory and are known as Lacquered Tweed "Relic" editions.
The "Blonde" and "Brown Tolex" Blues Juniors feature traditional Fender Tolex upholstery in their respective colors, while the Sunburst Ash edition features an ash cabinet with a sunburst stain.