Dagnall power transformer identification

Discussion in 'Let's Talk Vintage' started by Super Blead, Oct 23, 2020.

  1. Super Blead

    Super Blead New Member

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    Hi everyone,

    A few weeks ago, I bought a '71 Marshall JMP 50w with a 100w Dagnall power transformer installed. Some people told me that I had better to replace it for a 50w PT.
    So I'm going to sell it but before that, I woud like to know the exact model number.
    Some people told me that maybe this PT is a T2562 but I doubt it. It's clearly an early 70's model but the wires don't have exactly the same colors comparing to an upright mounted T2562 I got in my 70' Super Bass. I saw exactly the same PT in a '74 Super Lead but no idea which model of Dagnall PT it is.
    Here are the pics with and without end bells. Notice the stain of the old sticker on one end bell where the model number was impressed. Not there anymore, obviously.
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    [​IMG] [​IMG] [​IMG] [​IMG] [​IMG] [​IMG] [​IMG]
     
    Last edited: Dec 1, 2020
  2. Marshallhead

    Marshallhead Well-Known Member

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    Are you sure that’s a 100w transformer to start with?

    the Dagnall 100w power transformer could not be fitted in place of a Drake 50 without rebuilding the rectifier setup. The 100w has a voltage doubler bridge rectifier, whereas the 50w doesn’t.
     
  3. Super Blead

    Super Blead New Member

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    Yes I'm sure, that's a 100w PT.
    The rectifier was rebuit indeed, with a 27K resistor on bias tap (white wire) and HT center tap (yellow wire, unused and isolated)
     
    Last edited: Dec 1, 2020
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  4. Seanxk

    Seanxk Well-Known Member

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    Not entirely sure, but the PT looks mid 70's on, I'm sure the earlier PT's ( 69-70 ) had the copper shield soldered across the top.
     
  5. neikeel

    neikeel Well-Known Member

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    Importantly all the wires exit one side so it can be used in lay down or stand up amps.
    As you probably know the T2562 had black cloth covered heater wires.
    Most of these late 60s early 70s Dagnalls are pretty much the same spec. I wouldn’t get too hung up on it. If they have 6.3v heaters, 95v bias and 175-190 either side of the centre tap I would be happy.
     
  6. TAZIN

    TAZIN Active Member

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    It could be a Dagnall T3715.
     
  7. Seanxk

    Seanxk Well-Known Member

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    Have looked at my SB 100 there is a Brown wire ( voltage in I think ), but I can't see one here.


    Below is mine, can't find any info on net.
    Is this really a new number for the T2562?, perhaps as it was standing up? and then they thought why re number it and they went back to T2562.
    IMG_4012.jpg
     
  8. Super Blead

    Super Blead New Member

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    Thank you all.
    neikeel, yes it could be used in laydown amp. I know the T2562 have black cloth covered wires heater wires that's why I doubted my PT was one. This and, as Seanxk noticed, the gray wire on 220v tap instead of a brown wire in T2562. There is also a blue wire soldered to the standby switch on my PT and on T2562 it's a green wire soldered to a blue one itself soldered to standby switch. That's all differences I can see.

    TAZIN, it could be a T3715 or a T3556 too. :)
     
    Last edited: Oct 26, 2020
  9. TAZIN

    TAZIN Active Member

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    Did the T3556 also use the gray wire for the 220v tap? I know the T3715 does.
     
  10. Super Blead

    Super Blead New Member

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  11. Super Blead

    Super Blead New Member

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