Princeton Reverb Experts?

Discussion in 'Amps/Cabs Tech Corner: Amplifier, Cab & Speakers' started by FloridaSam, May 5, 2008.

  1. FloridaSam

    FloridaSam Member

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    I just picked up a 1979 Princeton Reverb (Pull boost is foot switchable).

    1. Should the voulme taper on this thing? Mine went from off to loud pretty quick and starts breaking up around 3-4. I took out the crappy pre-amp tubes and there was an unlabled tube in the 12AT7 spot. I replaced that with a Mullard 12AT7 and replaced the 12ax7 and 7025 with Mullards as well. The amp sounds A LOT better with NOS tubes but still breaks up pretty early. The power tubes are new JJs.

    2. Would swapping a 12AU7 in spot one, or other lesser gain tube tame it a bit or is there something wrong. The amp sounds pretty good to me and the reverb and tremolo both sound strong and good (as strong as a trem on a PR can be).
     
  2. teleman1

    teleman1 Supporting Member

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    You want less breakup??? Check and see if it is biased properly. Also, I believe you can get hotter or colder JJ tubes that could make a difference. BUt try putting in a 12at7 in the 12ax7 slot,(number 1). If that doesn't do it for you try a 12au7. Don't let any chumps tell you your amp, with the push/pull is any lesser an amp than an early 70's. I have a push/pull and have been hard pressed to hear anythng better than mine.
     
  3. slider313

    slider313 Silver Supporting Member

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    The JJ power tubes do add more volume. They seem to be more of a 7591A than a true 6V6 in tone. Try the new Tung Sol 6V6. They sound more like a good old 6V6 and hold up quite well.
     
  4. FloridaSam

    FloridaSam Member

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    Thanks guys. I used to own an old '74 PR about 15 years ago but my memory is cloudy :) I've read good things about the JJs and they seem to react more like 6L6 than my 6V6 amps. I have a ton of old RCA pulls so I think I'll try some lower gain preamps.
     
  5. strat71

    strat71 Member

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    Hi,
    :agree i rebuilt a 78 PR last year, and i also had problems since it started to overdrive at 3 on the volume pot...

    i checked everything three times before i noticed that the volume pot was linear...

    change it with a log pot and you'll overdrive at 7/8 on the volume pot... as all Fender should be... :rotflmao

    look at this (sorry in French)
    http://tahitigtr.canalblog.com/archives/fender_princeton_reverb_1978/index.html

    hope it'll help...
    Ben
     

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