First, it will be useful to you to understand the following five terms in order to choose the correct chart for dating your amp: refers to the two-tone woven fabric that covered many early amplifiers.
On early amps, this material was varnished to make it a more durable covering.
They included the Model 26 Deluxe, the Princeton, and the Professional.
Fender amplifiers began making a name for themselves with the Tweed series, so called because of their cloth covering, which is actually varnished cotton twill (tweed is a coarse woollen fabric, commonly used for jackets, coats and caps; it is often woven in a twill pattern, which is likely the reason for the confusion over naming.) They were produced for more than a decade and are now eminently collectible and praised for their sound quality.
A 1957 tweed Vibrolux was reported with a tube chart printed with circuit “5E3” (tweed Deluxe) instead of the correct 5F11 (see photo).
Clearly Fender wasn’t afraid to use incorrect parts when they were in a bind. The 5G12 Concert is the earliest version from very late 1959 and early 1960 so the existence of a tweed example, while extremely rare, is certainly plausible since Fender was making lots of tweed amps during the same time period.
It’s unknown if the tweed covering was a mistake (“Oops, I thought this was a 4x10 Bassman cabinet that I was covering”) or intentional, perhaps as a special order.
Non-Schumacher transformers – It’s been universally accepted that Fender only used Schumacher transformers on amps made in the 1960s and 1970s.
Every article I read says that on fender amps after 1989, the 2 letters at the beginning of the serial number denote the year and the ... it`s supposed to be in good condition with black speakers.
They are all very rare today and few have survived.
The first amplifiers made in-house by Fender is the Woodie series, built in 1946 through 1948.
: I have a Fender Blues De Ville I bought a few months ago.
If you look at the back of the amp on the inside right there is a QA sticker there will be two letters in black print, write them down and log on to Then go to the fender FAQs and click on the question how do I date my fender amp.