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1969 Fender Super Reverb SF Circuit ID

Discussion in 'Amp Central Station' started by HD28, Mar 31, 2021.

  1. HD28

    HD28 TDPRI Member

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    I am going to look at a silver face no drip edge SR on Friday and would like some help from y’all in trying to ID the circuit inside it without removing the chassis. If that’s possible.
    Serial number on back of chassis is A 423(6 or 5)1
    The number on the reverb transformer is 606-9-23
    It has a 2 prong plug.
    Any tips on what to be aware of?
    Thanks
     

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  2. ReverendRevolver

    ReverendRevolver Tele-Afflicted

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    The drip edge absence doesn't mean alot this far down the road; they used it on some models until it ran out. It ran out faster for some stuff than others.
    Non MV sf is one of a couple circuits I think people like the AB763 most, but I can't identify which is which, and most people who can need chassis pulled.
     
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  3. jondanger

    jondanger Poster Extraordinaire Silver Supporter

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    Transformer code indicates 23rd week of 1969.

    I’d estimate late 1969 to early 1970. Other folks may have a better suggestion on how to tell which SF circuit that would be, but you never know what may have been changed inside over the last 50 (!!!) years.

    My best suggestion is that if you plug it in and it makes a loud and moderately pleasing sound, that’s a good sign that all the important parts (transformers mostly) are operable, and any other issues with the circuit or other components can be addressed by a good tech.

    No master volume, so it doesn’t have the later SF changes, but there is at least one circuit revision between the BF and the MV SF amps that folks don’t love because of a weird biasing arrangement. That biasing can easily be changed to the BF biasing circuit though, so I wouldn’t consider it a dealbreaker.
     
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  4. Wally

    Wally Telefied Ad Free Member

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    Insufficient information to say much of anything.it appears that MAYBE the speaker in the upper left is not a CTS Alnico as are the others...hard to tell though but the edge of that label doesn’t look correct. I never buy a Fender amp without pulling the chassis to see what has been done. Now, if the asking price is NOT equal to what is asked for ‘excellent and all original condition’ and the amp makes decent loud sounds, maybe I am not so concerned. the transformer codes are important....the one you show is of m8nor importance versus the PT and OT.
    http://www.ggjaguar.com/biblio.htm

    Anyone getting into vintage Fender amps should copy and read the 6 articles found in the above link and entitled ‘Dating Fender Amps’. The info to be found there is invaluable. The serial number range you give us is listed listed as good for late 1969 or early 1970. Whether or not the amp is anywhere near original condition is another thing. It will have a bias balance circuit as opposed to the AB763 amps’ bias voltage adjustment. It will have started life as the 1969 circuit as that did not change again until later in 1970.
    it could be a great amp, or it could be a pile of troubles. In the best situation, be prepared to spend $250-300 dollars on it after the purchase.
     
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  5. HD28

    HD28 TDPRI Member

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    Thank you Wally.
    I will read these articles.
    And as always, caveat emptor.
     
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  6. HD28

    HD28 TDPRI Member

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    Can you offer any enlightenment on exported amps? This one, with the CSA (the Canadian equivalent of UL) sticker on it, was no doubt, destined for Canada.
     
  7. HD28

    HD28 TDPRI Member

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    Owner just sent me another picture.
    Transformer code 022699
    Date code 606-9-23
    I’m patiently waiting for more pictures, until Friday...
     

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  8. Wally

    Wally Telefied Ad Free Member

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    I don’t see a Switch for selecting different voltages. What do you get out of the wall up there?
     
  9. HD28

    HD28 TDPRI Member

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    120V
     
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  10. gridlock

    gridlock Poster Extraordinaire

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    I have previously owned both an early ‘69 Super Reverb with Drip-Edge and a late ‘69 without Drip-Edge. Both great sounding amps. Both definitely not BF circuits but pretty easy to convert to BF if desired.
     
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  11. HD28

    HD28 TDPRI Member

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    Brought this home today. It make nice noises. A few scratchy pots but all of them do what they’re supposed to do. Reverb and vib work with the original pedal. Speaker numbers all match. Transformer numbers are all 1969. Tubes are very old, I might say the originals. 2 amp fuse. It was sold to me by the son of a local musician who bought the amp new in Fargo ND. He played the accordion with this amp.
    So now the cosmetic restoration begins. Then, I go inside.
    Will post as it unfolds.
     

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  12. jondanger

    jondanger Poster Extraordinaire Silver Supporter

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    I spy with my little eye a Tung Sol 5U4.

    Very cool! You’re definitely going to want to have the bias and filter caps examined, and if they are more than ~10 years old they should be replaced. Folks here can walk you through it or you can pay a tech, but it’s as important as changing your oil.
     
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  13. HD28

    HD28 TDPRI Member

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    And here is the inside. All the tube numbers are as per spec. They are all branded RCA except for V8 which is Sylvania.
    Nobody has lifted the hood on this machine.
     

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  14. HD28

    HD28 TDPRI Member

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    V7 and the 5U4 show a silver “burn” mark. Overheated?
     

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  15. Andy B

    Andy B Friend of Leo's Silver Supporter

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    Very clean cool amp. Needs a recap and the bias section converted to BF specs. I see it is one of the amps that has a combination fixed and cathode bias that were made for a very short time. My personal Pro Reverb is slightly younger. Great amp.
     
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  16. HD28

    HD28 TDPRI Member

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    Thanks for the tip. I’m a very handy guy with nuts, bolts, mechanical, carpentry, plumbing, and electrical, but soldering gives me grief sometimes. AND DRYWALL! I HATE DRYWALL!
     
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  17. Andy B

    Andy B Friend of Leo's Silver Supporter

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    That is the getter flash from when the tube was manufactured.
     
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  18. Wally

    Wally Telefied Ad Free Member

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    That is the 1968 circuit...mixed Biasing...fixed and cathode. Clean amp.....I don’t see much cosmetic work to be done outside of some light cleaning. Nice...congrats.
     
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  19. HD28

    HD28 TDPRI Member

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    Cool, so perfectly normal?
     
  20. HD28

    HD28 TDPRI Member

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    Thank you.
     
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