1959s with polarity switch and 3 prong cord from Marshall

Discussion in 'The Workbench' started by Rotorcraft230, Sep 16, 2019.

  1. Rotorcraft230

    Rotorcraft230 Active Member

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    13DB80EC-5C14-4057-A4AB-F1B3EA008657.jpeg 60B5B860-D2DC-4176-AA2E-E5CAADE6B487.jpeg 167DF03E-67DA-41D4-B134-C2B0C43051A1.jpeg E3455A92-0AA3-4797-9971-B3641F723D3D.jpeg D3D783FC-D0A9-4831-B51C-7C2D0F9EDD21.jpeg FDF9A2AD-13C4-4294-8B10-11C84E738CB7.jpeg So I have been reading about the polarity switch and prettty much everybody says to remove the
    “Cap of Death”. Well I don’t know which one it is or even if it actually has one. We have a 1959s first reissue made in 1988. It already has the 3 prong power chord that I’m sure Marshall had to put on by law for import to the USA. What I can’t tell
    Is if the polarity switch actually works. Here are some pics and see what you guys think.
     
  2. john hammond

    john hammond Well-Known Member

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    i cant see no death cap, but I can see a bright cap that looks like the big assed 5000pf one that was in my 74, thats the only thing i'd change in this beauty, down to 500pf (mica)
     
  3. Rotorcraft230

    Rotorcraft230 Active Member

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    Hi John, thanks for the quick reply. That one on the volume pot? What would a 500pf do to the tone?
    And how about the polarity switch? Does it look operational? Is it dangerous like in the early 70’s ones?
     
  4. john hammond

    john hammond Well-Known Member

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    nah that polarity switch is not dangerous.
    the amp is good.
    i dont know if its operational, id have to have it in front of me, but i'd bet its just fine.

    that bright switch is on that volume pot, and a 5000pf one will give you a hairy, bright amp.
    When you just start to turn that volume, all hell seems to break loose early as you turn.
    A 500pf mica, a little bean shaped black thing, will smooth out this crazy action, and give the amp a less bright sound.
    You can experiment here with film and foil caps, ceramic ( that one is ceramic), mica etc.
    you can use values from 0 to 5000pf, you can take that cap right off, some people do.
    Its a tiny component that makes a big change

    late sixties amps used, I believe 100-350?pf something like that...seventies ones had 5000pf.
     
  5. Matthews Guitars

    Matthews Guitars Well-Known Member

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    Yes, that polarity switch is functional. Follow the wiring, it'll reverse the blue and brown (hot and neutral) connections.

    You don't need it. It really does nothing when you have a grounded 3 prong cord. Bypass that switch and then that switch can be used for other purposes, such as enabling a half power function if someone does that mod to it.
     
  6. Rotorcraft230

    Rotorcraft230 Active Member

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    Hey John thanks for the tips on the bright cap, we can experiment with different ones. And as far as the polarity switch I just didn’t want it to be a danger to the amp. Good that it’s not.

    Matthews guitars thanks for your input. A half power switch doesn’t sound too bad. This amp has 2 levels. Loud and LOUDER.

    Thanks Mark
     
  7. Rotorcraft230

    Rotorcraft230 Active Member

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    HeyJohn, gonnaget some bright caps. Is voltage rating anything to consider.

    Mark
     
  8. john hammond

    john hammond Well-Known Member

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    5 volts would actually be fine, just make it 25v or 50v
     
  9. Rotorcraft230

    Rotorcraft230 Active Member

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    Sweet thanks
     
  10. john hammond

    john hammond Well-Known Member

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    make sure you keep that cap, put it in a little plastic bag with a tag that tells you what its from
     
  11. Rotorcraft230

    Rotorcraft230 Active Member

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    Yep will do
     
  12. Rotorcraft230

    Rotorcraft230 Active Member

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    Hello all, whenI solder the new bright cap on does it matter which way?
    I would solder it with the info on the cap facing you so it can be seen easily.
    I don’t think it matters but then again I haven’t messed with ceramics much
    Mark
     

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