Princeton Reverb Reissue rectifier swap ?

Discussion in 'Amp Tech Center' started by Phil_tre, Apr 9, 2013.

  1. Phil_tre

    Phil_tre Tele-Holic

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    I have a New PRRI and I would like to experiment for different
    overdrive/crunch sound...

    In december, I found small crate of NOS JAN Sylvania 5Y3WGTA
    from 1975 and since the 5Y3 and the GZ34 (that came stock with
    the PRRI) are both 2 A current rated, is it safe to just swap them ?

    I will rebias, don't worry, but I have limited experience with tube
    amps (built a 5E3, did BillM BJr mods, etc.) and I don't want to burn
    something...

    And sound wise, I hope it will be about the same clean as with the
    GZ34 but with less headroom and a saggy overdrive maybe ?? Don't
    get me wrong, I love the sound of the Princeton as is, I just want to
    safely experiment...

    Thanks !

    Phil.
     

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  2. Ed Storer

    Ed Storer Tele-Holic Silver Supporter

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    Since the Princeton is only making 14 or 18 watts, the 5AR4 is way understressed, a 5Y3 shouldn't change the sound at all - it will be loafing as well. Getting sag from either one in a Princeton is a function of one's imagination.
     
  3. Rod Parsons

    Rod Parsons Friend of Leo's

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    A compressor might help achieve what you want in sag.
     
  4. Phil_tre

    Phil_tre Tele-Holic

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    Ok but is it safe to use it ???


    Phil.
     
  5. Silverface

    Silverface Poster Extraordinaire Ad Free Member

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    Yes
     
  6. Phil_tre

    Phil_tre Tele-Holic

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    Thanks !
     
  7. Wally

    Wally Telefied Ad Free Member

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    Phil, it would beinteresting to take measurements of voltages with the GZ34 and then with the 5Y3....B+, plate votlages not jsut in the power tubes but in the preamp. Take 'tonal' measurements before and after as well. (NOte: tonal lmemory is a tough nut to crack, isn't it? At least it is for m...when it gets to fine poitns.) PErhaps try to bias to the same plate dissipation factor for the power tubes with each of the rectifiers...just to be able to judge the difference in the circuit other than the power tubes, right?
    Ime, you are going to hear 'browner' sounds...mainly from the lower votlages in the preamp. That voltage change will change the bias in the preamp, and I do believe that you might get a more 'reactive' amp with a bit more compression in the circuit.
     
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