Question about Fender amp circuit designations.

Discussion in 'Amps/Cabs Tech Corner: Amplifier, Cab & Speakers' started by Strung Up, Nov 19, 2005.

  1. Strung Up

    Strung Up Member

    May 16, 2005
    Crazy, mixed-up world
    I asked this in "Amps and Cabs" and got crickets, still curious:

    I should know this, but don't:
    1. Are all the old Fender circuit designations (5E3, etc.), Western Electric circuits?
    2. What the heck is the 'key' to the alph-numerics?

    Like any of that is going to make me a better player.

  2. Curly

    Curly Member

    Mar 19, 2005
    well, the tweed Bassman and Deluxe were certainly licensed from AT&T and Western Electric
  3. markdurham

    markdurham Member

    Sep 11, 2005
    No. Those designations are Fenders. Take the Deluxe for instance. The first one with this designation was the 5A3, then the 5C3, 5D3, 5E3. These all came out in the 50's. All the Fender amps in the 50's had 5 as the first # of the designation.
    The letter refers to the circuit revisions. A=first revision, etc. Not all of these revisions saw the light of day as production amps. The last # is the model#. The Deluxe is 3, Bandmaster is 7, Bassman is 6, etc.
    When the 60's came along the first # changes to 6. Look at the brown Deluxe, it's designation is 6G3. 6 for the 60's, G for the new revised circuit(what happened to the F revision, I don't know), and the model # is 3.
    Later they used a different designation. Like the AA763 and AB763 Deluxe Reverbs. The AA was the first circuit and the AB was the second circuit(almost identical). These amps were designed in July of 1963, hence the 763. I have an AA763 that was made in Oct, 1963. It has the different component values that you see on the AA763 schematic. There was also the Deluxe Reverb AB868(Aug.,1968) and A1270(Dec.,1970).

    These designations were not WesternElectric or AT&T circuits. All of the early Fender tube charts have some boilerplate about the circuits being licensed under the patents held by WE and AT&T. You can see it on this tube chart from a 1955 Fender "White" amp.

    But I don't think they mean the exact total circuits. I have searched through as many old schematics as I can find of WE, AT&T, and RCA tube amps that predate the Fender amps and I can't find any that have the exact circuit of a Fender Deluxe or Bassman. Those patents were for parts of the circuits that Leo put together for his amps. It's hard to imagine having a patent on the classic arrangement of a common cathode preamp gain stage, but WE did. And this was one thing that was seriously litigated back in the day. I don't know if Fender actually paid any licensing fees. More likely it was included in the price of the tubes he was buying.
    When CBS took over, they dropped the language on the tube charts(and the charts all together soon after). I don't think they could be intimidated by the tube companies cause' they had lots of lawyers themselves. And those patents ran out before that anyway.
    If anyone can find a WE, RCA, or AT&T schematic that is identical to any Fender Deluxe or Bassman please set me straight.
  4. Strung Up

    Strung Up Member

    May 16, 2005
    Crazy, mixed-up world
    Thanks Mark!

    Part of my question was wondering just how indebted electric guitarists, rock and roll, etc. are to Western Electric (then the R&D arm of the giant AT&T, pre-breakup). The answer seems to be something less than 'totally'. More props to the gang at Fullerton and their counterparts across the pond.
  5. TheAmpNerd

    TheAmpNerd Member

    Sep 23, 2004
    I guess if you are
    looking for an exact circuit/amp.

    If I recall, Western Electric was unable to "make a profit"
    from an implementaion. I think Dr. W. Edwards Deming discussed during a seminar I attened. W/E was the manufacturing arm of The Bell System.

    Bell Labs, the research arm of the organization. Amoung them William Shockley. Shockley a tri-inventor of the transistor and tri-Nobel Laurette. Shockley started his own
    comany (?) followed by folks from his to start
    Fairchild Semiconductor, followed by the kind folks
    who gave us PCs, namely INTEL.

    Therefore, they liscenced or gave
    rights to certain companies, Texas Instruments
    comes to mind.


    Transistors, Semi-conductors, related processes
    were all developed by Bell Labs.

    In light of this new information, I would say
    totally, including the audio age, the television age
    and then the "digital age".

    I was looking for my book signed by Demning


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