5u4 Rectifier in Brownface Princeton?

Discussion in 'Amps/Cabs Tech Corner: Amplifier, Cab & Speakers' started by PlumBob, Apr 29, 2008.

  1. PlumBob

    PlumBob Member

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    Does anyone have thoughts on this? Anyone running a 5u4 rectifier in a Princeton 6g2? I just got my 1962 Princeton back from Dennis Kager at Central Jersey Music, and he changed out the 5y3 for a 5u4 as a way of reducing the amount of crossover distortion. I had asked him to do what he could about the harsh, nasty distortion characteristics I was getting with the amp. The 5u4 does improve the sound of the amp's distortion quite a bit. Dennis said the transformers and caps in the amp can handle the 5u4 fine. I'm curious whether anyone has experience with or thoughts about this swap.
    Thanks.
    -Matt
     
  2. Bonenut

    Bonenut Member

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    I'm not sure about the 5U4 but I can tell you that I run a 5AR4 in mine which helps the sound a lot and gives a slow turn on for the power tubes.
     
  3. PlumBob

    PlumBob Member

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    Yeah, I was kind of amazed at the improvement in the sound of my amp. I guess the bias circuit was operating in such a way as to work better with the 5U4 than with the 5Y3. But the amp was designed for a 5Y3, right? I'm still a little confused...but pleased with the sound.
     
  4. phsyconoodler

    phsyconoodler Member

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    The rectifier change only increases voltage.It may be that the stock bias was wrong,and an increase in voltage to the the plates was needed.However,the bias voltage is unaffected by changing the rectifier tube.You need more info before you simply say a 5u4 made my amp sound better.There are other things you can do to get better tones from your princeton that don't involve a rectifier change.
     
  5. PlumBob

    PlumBob Member

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    Yes, it stands to reason that one could change the bias to suit the voltage from the 5Y3 or change the 5Y3 to suit the existing bias. My tech decided on the latter course, and it improved the sound of the amp. Do you think I should take it back to him and suggest that he approach it the other way?
     
  6. phsyconoodler

    phsyconoodler Member

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    Not if you are happy with it.I was merely suggesting there are far more that can be done to get even better tones yet.
    I think your tech is knowledgeable and is holding back a few tricks in reserve.:dude
     
  7. PlumBob

    PlumBob Member

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    Now I'm really curious. You think he's holding out on me? So if I take it back, he could bump it up a notch? I feel like I'm at one of those restaurants where you need to be able to read Chinese if you want to order the really good stuff. Otherwise, you just end up with General Cho's Chicken...
     

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