Hammond 290CAX wiring question

Discussion in 'Shock Brother's DIY Amps' started by tubeToaster, Jul 21, 2021.

  1. tubeToaster

    tubeToaster Tele-Meister

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    I have a 290CAX in my 5f2a build and have it wired for 120 volts primary like this

    upload_2021-7-21_17-40-51.jpeg

    My question is should it be wired like this with the two halves parallel ?


    upload_2021-7-21_17-43-36.jpeg
     
  2. andrewRneumann

    andrewRneumann Tele-Holic

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    I vote yes.
     
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  3. 2L man

    2L man Tele-Holic

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    Yes parallel is correct way for 120VAC. It would produce output voltage using only one primary half but that primary section would heat and possibly destroy when more than half rated current is delivered.
     
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  4. tubeToaster

    tubeToaster Tele-Meister

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    Thanks guys. @2L man I saw your post about this in another thread and it got me thinking about how I had wired it. So I checked and I did it wrong. Glad I saw your post. I guess a 5f2a circuit running on 57.5 mA probably wouldn’t fry the transformer but I am going to re wire it to the correct way in case I decide to run a 6L6 in it. I put a Hammond 125DSE and this 290CAX in there to have that option.

    Thanks, Dave
     
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  5. jsnwhite619

    jsnwhite619 Friend of Leo's

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    I've used a few of those. Black & brown in this pic. I remember bthe orange & white together I think.

    Screenshot_20210722-003713.png
     
  6. jtcnj

    jtcnj Tele-Holic

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    Yes, parallel both windings.
    I have used that PT and I believe the wiring diagram shows that as well.
    EDIT: It was a sticker ON the box; not a sheet IN the box.
     
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  7. chas.wahl

    chas.wahl Tele-Meister

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    I bought one of those 290CAX transformers for a projected 5F2-A build, but decided not to use it because it's a monster. It weighs 40% more than the 290AX (newer model that's also dual-secondary, unlike the older model, which was only 325-0-325V)
     
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