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.
Unlike the auto industry which has specific model years for their products, most specifications for a given Fender instrument model, change little if any, through the lifetime of the model.
While there have been periods where dramatic changes have occurred, for example: the transition periods between Leo's Fender and the CBS years, as well as the transition between CBS' Fender and the current ownership, generally speaking, most models are feature specific and do not change from year to year.
Oddlings – Yet another printing error has surfaced, this time from the FEI (pre-CBS) days.
Besides, no article in the Dating Fender Amps by Serial Number series would be complete without some interesting information, n’est ce pas?
Information on Japanese and Mexican-made instruments is included towards the bottom.The Jazzmaster featured several distinct differences compared to the Fender guitars that came before it.The body was somewhat larger, and featured an "offset" waist design, where the narrowest part of the contour of the guitar's waist is closer to the bridge on the high E string side, and closer to the neck pickup on the low E string side of the body.It would be more accurate to say that approx 650 of each of these models were produced in ’60. There were periods of time when this was not consistently done, (between 19), and there are certainly other examples of short periods of time, and individual pieces, where the dating was simply omitted.Other things to look for include chasses placed in cabinets from a different year, “doctored” tube charts, non-original control plates (usually reproductions) on silverface amps, original transformer bell ends (they have correct date codes, of course) on non-original transformers, and non-original knobs (either repro or silverface knobs on blackface amps).unusual things can be found such as the empty “Pulse Adjust” hole on the rear of early ’60 brown amps, the “middle” volume control, use of tweed style grill cloth, strange non-documented transitional circuits, and changes in tolex color including the super-rare cream colored “brown” tolex that is found on some late ’60 amps. Given that people may refer to this information seeking specific production quantities of amps they are curious about, it should be pointed out that the serial numbers apply to chassis types, and not specifically to amplifier models.Looking at serial numbers next to the ’60 5G5 brown Pro Amp for example, we see numbers ranging from 00001 to 02000, suggesting that there are 2000 of these amplifiers made in ’60.Some things are very obvious such as non-original or reconed speakers, non-original transformers, replaced pots, re-tweed, re-tolex, re-grill, etc.and these changes are often disclosed and of a non-malicious nature.This improves player comfort when holding the guitar while seated.The Jazzmaster also was the first Fender guitar to feature the new rosewood (as opposed to the earlier maple) fretboard.Given the modular nature of Fender's production techniques, an individual neck may have been produced in a given year, placed in the manufacturing warehouse and remained in stock for a period of time, and then subsequently paired with a body to create a complete guitar in the following year.So, obviously a neck date, while being helpful in providing a date range of production, it cannot be a definitive reference. I promise the tables will still be there after you finish reading.