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73 twin reverb circuit

Discussion in 'Amp Tech Center' started by Steve77, Jan 24, 2021.

  1. Steve77

    Steve77 TDPRI Member

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    Super quick question. Sick of digging around looking for this.
    Bought a 73 silver face twin reverb. Master volume push/pull.
    what circuit was used in it?
    I think 73-75 were the same MV with push/pulls.
    I have found one that has the master volume push/pull, 100 watt but no label as to which circuit it actually is.
    After I get it up and running and decided what I think of the tone I may blackface it, but am trying to compare schematics and knowing which I’m using would be great.
     
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  2. BobbyZ

    BobbyZ Doctor of Teleocity

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    Good luck! I've only seen one schematic for the 100 watt pull boost MV. That one doesn't have the "hum balance" pot on the back that a lot of those amps had, closer to when the ULs came out.
    What's your plate voltage? Some of them are right at blackface voltage, like that one schematic and some are lower like the earlier non master silverface circuits.
     
  3. Jon Snell

    Jon Snell Tele-Holic

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    These any good?

    Screenshot 2021-01-25 at 08.29.57.png Screenshot 2021-01-25 at 08.30.30.png

    They are all very similar and have similar voltages and values.
     
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  4. BobbyZ

    BobbyZ Doctor of Teleocity

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    That one for the 100 watt I'm pretty sure is the same one I always see, and of course the other is the ultra linier 135 watt.
     
  5. BobbyZ

    BobbyZ Doctor of Teleocity

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    twin_reverb_sf_100_schem.jpg
     
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  6. Jowes_84

    Jowes_84 Tele-Meister

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  7. Jowes_84

    Jowes_84 Tele-Meister

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    Oh and mine is a late 74 - should be the very same circuit.
    Have fun with the amp.
    I like mine stock except for the boost which I changed to a Rivera/Jahns style arrangement. not what people do usually but „blackfacing“ it seemed too much trouble for me.
     
  8. BobbyZ

    BobbyZ Doctor of Teleocity

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    As far as blackface mods my two TRs are a 65 blackface and a 76 SF. Only thing I did with the 76 was add a trim pot ahead of the bias balance pot and service it with all new electrolytic caps. I guess the first two filter cap values I used are a nod to blackfacing @ 80uf. Truth is they were here, no waiting, hate waiting.
    Sound wise? Most days I prefer the beat up 76, not by a lot really. A big part of that is its lower sensitivity speakers, if I run a cord over from the blackface to the Radio Shack Utahs, it's a tie.
     
  9. Ten Over

    Ten Over Tele-Holic

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    The 100W push/pull MV models continued into the first part of 1977 with only minor changes.
    Twin Reverb 1974 100W.png
     

    Attached Files:

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  10. Steve77

    Steve77 TDPRI Member

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    Wow great diagram thanks!! Certainly gonna leave it for a bit and see if works for me.
     
  11. Steve77

    Steve77 TDPRI Member

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    Thanks for all the responses guys. Ya the schematic you guys posted is what I’ve got too. I suppose it doesn’t really matter what the name of the circuit is.
     
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