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  • Transformer wire layout help

    I'm planning on building a marshall style 50 watt amp ,hopefully using 2 5881's or 2 el34 & 3 preamp tubes
    I have this 40 watt Ashdown peacemaker 40 that i would really like to use the trannys from .as this build would not be in the budget without the freebe trannys
    So to get things rolling these trannys powered 4 el84's & 4 12ax7's
    I need some help with the pinout of both the power & output trannys
    Void the yellow arrow /circle ,it's from a previous thread.



    Power transformer
    red & red = heaters 6.3vac
    Blue=
    Blue=
    yellow=
    black=
    yellow=
    I noticed the blue goes to some big electrolytic's maybe the B+
    Yellow goes to diodes..... Rectifier ?
    & black could be a ground

    OUTPUT tranny
    I may have figured out but not 100% about the last 4
    Blue=16ohm
    Yellow=8ohm
    white=4ohm
    Green= Ground or common ? is common the ground ?
    Red=center tap
    Black = Anode
    Brown=Anode 2 ..Please feel free to discuss this
    "UP here in the Canada we shoot things we don't understand"

  • #2
    The yellow-black-yellow is probably around 24 to 28 VCT. It goes to the regulators and also powers the preamp heaters with DC. The blue-blue is about 240VAC for the high Voltage. This is not center tapped so you'll need a full wave bridge to rectify it, just like the schematic. Red-red (unusual color choice) appears to be 6.3VAC for the power tube heaters. There should be enough current to power two EL34s or 6L6/5881s. I don't see anything to indicate what the PT primary might be. That might be confusing if there are multiple mains Voltage selections.
    WARNING! Musical Instrument amplifiers contain lethal voltages and can retain them even when unplugged. Refer service to qualified personnel.
    REMEMBER: Everybody knows that smokin' ain't allowed in school !

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    • #3
      Here's some pics

      "UP here in the Canada we shoot things we don't understand"

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      • #4
        loudthud has the PT secondary for you. As far as the primary, just wire it like it is in the original amp. Looks like parallel windings for 110-120V operation. Looks like you already have the OT figured out.

        Edit: And yes green is ground.
        "I took a photo of my ohm meter... It didn't help." Enzo 8/20/22

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        • #5
          Great I'm leaning toward building something like this so if we can apply my trannys to this layout

          & I've noticed this amp uses dc heaters as well
          Any help as Loudthud explained the yellow/Black /Yellow or (orange) goes to the regulators & the dc heaters I guess that is the small board to the far left ?
          "UP here in the Canada we shoot things we don't understand"

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          • #6
            Originally posted by copperheadroads View Post
            Any help as Loudthud explained the yellow/Black /Yellow or (orange) goes to the regulators & the dc heaters I guess that is the small board to the far left ?
            No, that board is a Voltage Doubler meant to run from a 5VAC heater winding and convert it to 6VDC.

            The Ceriatone layout also uses a center tapped winding for the B+. That won't work with your transformer.

            Your transformer has about 24VAC center taped and after the regulators creates plus and minus 12.6VDC. Your transformer could be wired to make a single 12.6VDC supply if you don't need the +/- supplies for the solid state stuff.
            WARNING! Musical Instrument amplifiers contain lethal voltages and can retain them even when unplugged. Refer service to qualified personnel.
            REMEMBER: Everybody knows that smokin' ain't allowed in school !

            Comment


            • #7
              Thanks for the help
              I will have to do some research on what to do with the heaters for the preamp tubes
              I guess wiring it more like a traditional JCM800 wont help me much . I wonder if there is enough amps in the 6.3v winding to supply all the tubes with AC ? like the jcm layout
              I may stick with a traditional layout as well
              "UP here in the Canada we shoot things we don't understand"

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              • #8
                This project has taken a turn as I have ordered transformers for my marshall build so that gives me this for another future build ,Just wondering if i could use these trannys for a amp with a rectifier tube like a bassman or similar .
                "UP here in the Canada we shoot things we don't understand"

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                • #9
                  Originally posted by copperheadroads View Post
                  Just wondering if i could use these trannys for a amp with a rectifier tube like a bassman or similar .
                  You can use a tube rectifier, but you will need two silicon diodes to complete the bridge because the transformer has no center tap on the HV winding.
                  WARNING! Musical Instrument amplifiers contain lethal voltages and can retain them even when unplugged. Refer service to qualified personnel.
                  REMEMBER: Everybody knows that smokin' ain't allowed in school !

                  Comment


                  • #10
                    Originally posted by loudthud View Post
                    You can use a tube rectifier, but you will need two silicon diodes to complete the bridge because the transformer has no center tap on the HV winding.
                    Ok... Thats works ...
                    What would you do with the Yellow /black/Yellow wires tape them off ?
                    "UP here in the Canada we shoot things we don't understand"

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                    • #11
                      I thought you wanted to use the Yellow/black/Yellow winding for preamp DC heaters. The 6.3V might not have enough current for EL34s and four 12AX7. I forgot to mention you will need 5VAC for a rectifier tube. No 5V winding on the transformer.

                      Tape is not a great idea for an unused winding. Heat shrink tubing is safer, just get the right size and shrink it tight so it won't fall off.
                      WARNING! Musical Instrument amplifiers contain lethal voltages and can retain them even when unplugged. Refer service to qualified personnel.
                      REMEMBER: Everybody knows that smokin' ain't allowed in school !

                      Comment


                      • #12
                        This is a build or 2 away but suggestions on what to build . Love to do some sort of bassman circuit with a tube rectifier but with no 5v winding on the tranny . would either a 6v rectifier tube like a 18 watt marshall ez81 has or a dc rectifier be possible
                        "UP here in the Canada we shoot things we don't understand"

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                        • #13
                          Ok getting back to this build or conversion my plans may of changed on what circuit as i'm gonna be building a 2 6l6 power section & 3 or 4 preamp section of some sort of amp with no fancy rely switching channels & possibly a single channel
                          so to get the DC heater circuit started Click image for larger version

Name:	ashdown dc heater circuit.jpg
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                          I'm assuming it's 15vac from the transformer i am assuming the +12.8v & -12.5v are the heaters ,PL2 would work for the 12vdc pilot light ?
                          & in this schematic what is the CHI ? at the end of circuit
                          "UP here in the Canada we shoot things we don't understand"

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                          • #14
                            CHI might be a connection to the chassis.
                            WARNING! Musical Instrument amplifiers contain lethal voltages and can retain them even when unplugged. Refer service to qualified personnel.
                            REMEMBER: Everybody knows that smokin' ain't allowed in school !

                            Comment


                            • #15
                              Ok Great so i guess I'm on the right track
                              "UP here in the Canada we shoot things we don't understand"

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