64 Vibroverb tranny quest

Discussion in 'Amps/Cabs Tech Corner: Amplifier, Cab & Speakers' started by LesFender, Sep 13, 2005.

  1. LesFender

    LesFender Member

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    Guys,I have a '64 vibroverb that is,circuit-wise,original.The amp sounds weak to me(a little thin and distorts too easily).I have changed the electrolytics.I have messed with different bias settings.The tubes are nos 7581s.The speaker is not part of the issue.I suspect the output tranny is not in great shape as I measure 60 ohms on one side of the primary and 86 on the other.My question is:should I get a replacement and keep theoriginal one for when I sell the amp years from now or should I get this one rewound?If I do get this rewound who should I send it to?I would like to play and enjoy the amp but don't want to hurt the value too much.The amp is not that enjoyble to play as is.I appreciate any ideas/suggestions.Thanks,Jack
     
  2. Jeff Flowerday

    Jeff Flowerday Member

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    A good place to start your research.

    www.mercurymagnetics.com

    Their Axiom trannies are some of the best vintage Fender reproductions.
     
  3. LesFender

    LesFender Member

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    Thanks for that info.Anybody else got suggestions?How 'bout rewinding?
     
  4. jcs

    jcs Member

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    schumacher trannys are available widely as they were used for years by fender,yours is probably a 125a7a 8 ohm like in my 62 bandmaster..

    there are many companies making great repros as well,some folks upgrade to the super reverb ot but it wont saturate as quick as the smaller one...

    you should be able to locate a used one easy enough...
     
  5. LesFender

    LesFender Member

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    Thanks again!Still looking for thoughts on re-winding.
     
  6. Jeff Flowerday

    Jeff Flowerday Member

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    IMO,

    Rewinding:

    Original tranny is worth more in the end.

    I'd probably run a MM tranny until you sell. You could also look at finding another original...
     
  7. LesFender

    LesFender Member

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    Good point.If anybody has a good original or knows where one can be found,please let me know.Thanks,guys,Jack Hamilton
     
  8. sundaypunch

    sundaypunch Member

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    If it were mine I would leave the original tranny alone. A replacement is only of value if it is the proper type and has the right date code. It's going to be very expensive to buy and take quite some time to find one. If you are set on one I would look for a BF non-reverb Pro from the same time period. It has the identical tranny. If you can get the Pro for a reasonable price you can swap the tranny out with yours and resell the Pro (probably for not much less than you paid).

    That being said I would put the tranny on the shelf for a future time when you might sell the amp. I would get a better replacement to use for now. The wimpy tranny in the Vibroverbs is their weak link. It is amazing how much those amps are improved by a larger output transformer. A Bassman or Twin will do (with the proper tap / ohms). Just make sure to use existing holes when you mount it. I had one for several years and was amazing how much better it was than a stock Vibroverb. I sold it to a friend who now has three of them. He has swapped out the trannys in his other two since they sounded very thin compared to the one I sold him.
     
  9. LesFender

    LesFender Member

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    Thanks,I just installed a Mercury Magnetics Axiom Tranny.It sounds great and Paul from that company was very helpful.I had installed it with the same colors to the primary as the Fender tranny had.It squealed and sounded distorted.I tried all kind of stuff to make it sound right.Turns out it was just out of phase.I switched the wires and it became a thing of beauty.I will keep the original one for posterity.Right now I'm enjoying the vibroverb.Thanks to all,Jack
     

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