So what does AA763 really mean anyway?

Rich_S · Jan 5, 2006

I've been looking at schematics for my upcoming Bogen-butchery project. Thinking this amp will make a good "Fender" I started looking at 2x6L6 schematics, AA763, AB763 and the 6G12-A Concert.

What's up with Fender's numbering scheme? I see so many schematics all labeled AA763 - Super Reverb with tube recto, Bandmaster (no reverb) with SS recto, Showman with SS recto and 4 output tubes. Yeesh!

The Bogen already has a tube recto, so I guess I'll make it a sorta Super-clone, but as a head only. Which is the "classic" Super Reverb schematic, the AA or the AB?

Anybody know how the Super and the Concert differ tonally? They're both 2x6L6 4x10" combos, but the Concert has SS rectifiers and (counter-intuitively) lower voltages throughout. Weird.

Maybe it should be a JTM45 instead.:smack:

Curly · Jan 5, 2006

Re: So what does AA763 really mean anyway?

ooo ... good question ... I've kinda wondered that myself, since several circuits are designated A-763. Maybe it was a date - 7/'63 - of the first version of the circuit

BTW, I think the Deluxe Reverb RI circuit is also probably AB763.

just a guess, but I don't have time to check right now ... maybe the Fender Field Guide has some info?

jeremy · Jan 5, 2006

Re: So what does AA763 really mean anyway?

my dlx reverb says ab763 on the tube layout sticker

Curly · Jan 5, 2006

Re: So what does AA763 really mean anyway?

I checked the Fender Amp Field Guide - for a Deluxe Reverb, it list the dates as '63-'67, so I'm still guessing that "763" refers to the date of the first circuit
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upon further looking in the FAQ:

Circuit Code: In 1963 Fender stoped using model numbers to identify schematics and began using the model name and an assigned circuit number. These circuit numbers which are located on the tube chart can be usefull for getting a rough date on an amp. Fender often used the same circuit for many years so this is not a very accurate method for amp dating. The code is simple, the first two letters are the revision, where AA is the first revision, AB is the second, etc. The next one or two numbers are the month where January is 1 and December is 12. The last two numbers are the year.
Example: AB763 = second revision, July, 1963

JumpMarine · Jan 5, 2006

Re: So what does AA763 really mean anyway?

I compiled an Exel spreadsheet of the data from the Fender Amp Field guide on all of the specs and circuit #'s for the individual amps. Shoot me a pm with your email and I'll send you a copy. This goes for anyone who wants a copy.

JumpMarine · Jan 5, 2006

Re: So what does AA763 really mean anyway?

I tried uploading the zipped file before and it didn't work, but did this time. Here you go for anyone who wants it.

ES350 · Jan 5, 2006

Re: So what does AA763 really mean anyway?

The brown-era Concert was the 4x10" replacement in the product line for the 5F6A Bassman (after the Bassman went to piggyback)...model continued into BF era. Differences---SS rectifier, no mid control, no reverb available, it got dropped about, what, 1964-65 or so? Basically a Bandmaster (same chassis size) with a Super OT. There was no such critter as a non-reverb BF Super.

I don't know about plate voltages on the BF's, but the brown era Concerts had pretty high B+. Tonally, the BF Concert is close to a Super Reverb, not quite as much headroom, with perhaps a tad more front end 'gain' due to no reverb losses.

BTW---why bother doing the BF thing to the Bogen? Why not a 5F6A or a 5E7? The BF is a lot more trouble, more insertion loss, more parts---?