Fender circuit designations

[LeftyStrat]

Found this snippet on my hard drive, don't remember where I got it from. Thought it might be a handy reference for out new Fender section.

These designations were used up until the Blackface Era amps and apply to Tweed, Blonde, and Brown-era Fender amps.

The first number is the decade.
5) Fifties
6) Sixties

The middle letter is the year of the most recent circuit design change or update.
A) 1950
B) 1952
C) 1953
D) 1954
E) 1955
F) 1956
G) 1959

The last number is the amp model, according to this list:
1) Champ
2) Princeton
3) Deluxe
4) Super
5) Pro
6) Bassman
7) Bandmaster
Twin
9) Tremolux
10) Harvard
11) Viborlux
12) Concert
13) Vibrasonic
14) Showman
15) Reverb Unit
16) Vibroverb


So a 5F4 would be a 1950's(5) 1956 Circuit update design(F) Super(4).
A 5E7 would be a 1950's(5) 1955 Circuit update design(E) Bandmaster(7).

Corrections welcomed.

[jazzyjoepass]

Anyway to make sense of the later blackface designations ?? Eg. AA270 ???

[LeftyStrat]

Maybe someone else can chime in. I'm not really sure. I think the first two letters for for revisions so

AA
AB
AC
...
AZ
BA
...

The three numbers represent the month and year of the circuit design (or release?). So AB763 represents the second revision to the circuit first designed or released in July 1963.

[rdjones]

Maybe someone else can chime in. I'm not really sure. I think the first two letters for for revisions so

AA
AB
AC
...
AZ
BA
...

The three numbers represent the month and year of the circuit design (or release?). So AB763 represents the second revision to the circuit first designed or released in July 1963.

Yep, that's pretty much it.

Note that there's a few examples where AA or AB may have been skipped.
I think these represent circuits that had prototypes that were not released to production, even though a design may have been made and tested.

There's also some confusion where the same AB763 is applied to several different models (with a few different component values) and even variations with and without reverb.
So in the case of Blackface models onward you really need both the circuit designation and the model name.

I really like the Tweed/Blond/Brown system better, too bad Leo changed the system.
Anyone for a 7S8B Silverface Twin ?

rd

[wyatt]

The middle letter is the year of the most recent circuit design change or update.
A) 1950
B) 1952
C) 1953
D) 1954
E) 1955
F) 1956
G) 1959

Corrections welcomed.

It is not a year designation. It is the revision of the circuit, but the years are more of a rough rule of thumb, but aren't set in stone...

Just some exceptions...
5E11...1956
5F11...1957
5F6...1956
5G9...1957
6G3...1961

I think the deal was the numbers correspond better for the early years because Leo and his boys rolled out annual updates, and they become more erratic after 1955.

[tooold]

I think the deal was the numbers correspond better for the early years because Leo and his boys rolled out annual updates, and they become more erratic after 1955.

Or maybe less necessary - that they realized they'd taken the circuits as far as they could (for what they were after), and their attention started to focus on what would become the browns/blondes.

This is not a knock at all on the earlier tweeds, which are actually my favorites. Also worth noting that, by the mid-50's, they had a whole lot more models than they did in 1950.

[Randall]

Good stuff. Interesting.

[dorrisant]

Thanks for posting. I was looking for something like this.

Tony