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5F2 from parts on hand.

Discussion in 'Shock Brother's DIY Amps' started by Bill Moore, Oct 19, 2020.

  1. Bill Moore

    Bill Moore Tele-Afflicted Silver Supporter

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    I 'm looking through my transformer bucket, and find a couple of transformers from a Valve Junior that got the MM upgrade. I assume EL84, and 6V6 will require similar voltages, I got to thinking about a 5F2, only with a full wave rectifier.
    I checked the PT, although listed at 260V on the tag, yields 292V AC on it's own. With a full wave rectifier, won't I gain a little more voltage? Will a 6V6 be happy with those voltages?
    The OT is a little wimpy also, but has 4-8-16 ohm output. I'm looking at $60 for a chassis, but everything else I have, (or can build).

    20201019_170247.jpg
     
  2. dunehunter

    dunehunter Tele-Holic Double Platinum Supporter

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    Others may have a more informed opinion, but 292V seems a bit on the light weight side...
     
  3. kleydejong

    kleydejong Tele-Holic

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  4. elpico

    elpico Tele-Afflicted

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    Should make over 360Vdc once rectified
     
    jsnwhite619 likes this.
  5. jsnwhite619

    jsnwhite619 Friend of Leo's

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    Which would work just fine for this project. My last few have been between 340v B+ and 380v B+ depending on the secondary I used. I can tell a difference and kinda prefer the lower end, but it's probably unnoticeable to just as many people who can tell a difference.

    I would think that 360v and a SS rectifier is going to be a lot cleaner than what you might expect for it though. If it ends up cleaner that you like, try raising the NFB to 56k, and increase the V1 .022uf coupling cap to .033uf. I tried that on one with a GZ34 rectifier once and it warmed & dirtied it up kinda like a mini 5e3. But, it still wasn't close to the same sound and response as the stock 5y3.
     
  6. Bill Moore

    Bill Moore Tele-Afflicted Silver Supporter

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    Thank you all!
    I'm thinking this will be a harp amp for my brother in law. Once in a while when we get together to jam, he'll decide to play a little. (I even carry a few harps in my spares bag, just in case we get him to join in).
    A small SE amp with a 12, will be easy to just bring along, and get him in, if he feels the urge.
    (Thanks for the link to your project, kleydejong!)
     
    Last edited: Oct 20, 2020
  7. gusfinley

    gusfinley Tele-Afflicted

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    The transformer will produce less voltage over load.

    Also, you'll need to use a bridge rectifier since the PT does not have a center-tapped secondary.

    That transformer set should be fine for a 5F2.
     
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