Princeton Reverb question - too clean

Discussion in 'Amps and Cabs' started by Phyllo, Apr 18, 2008.

  1. Phyllo

    Phyllo Member

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    Hi, I have a silverface PR that has become my favorite amp. To my knowledge (which is minimal) it is stock other than the Weber Sig 10 alnico I put in it. I put new tubes in, a mix of JJ 6v6 and EH 12ax7 as shown on the chart.
    I love the amp, but most other PR's I've seen/heard overdrive at much lower volumes than mine. It has to be up around 7-8 to really get cookin' and that's wayy too loud for my practice environment. It sounds great with just about any pedal, but I'd like it to overdrive at a lower volume on it's own, if possible, with minimal or no mods.
    Is there anything really basic that I can do to achieve this?
    I play LP and a modded Tele with humbuckers.
    Thanks for any/all help.
     
  2. Bob V

    Bob V Member

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    I used to get a dirtier sound out of my '71-ish silverface Princeton Reverb by turning up the tone controls which are somewhat active parts of the preamp stage, then pushing it a touch with either a TS-9 or maybe just an MXR Micro Amp (just a clean preamp boost pedal). A more drastic step would be to use weak 6L6's and rebiasing as an alternative to the 6V6 power output tubes (Groove Tubes used to sell weak 6L6's as "6V6-HD") - I tried that and went back to the 6V6's. Problem for me was that it was just the right amp for rehearsal volumes but not enough to be heard with a band live. I've read about master-volume mods to those amps but I wouldn't desecrate the amp.
     
  3. Blue Strat

    Blue Strat Member

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    7-8 before breakup doesn't sound right for a PR. I've never played through one that wasn't breaking up by 4-5 with humbuckers.

    You might want to have the amp checked out.
     
  4. fullerplast

    fullerplast Senior Member

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    Agreed. Something is very wrong if you can't get breakup with a LP.

    Also, don't use 6L6's in that amp, of any type. They draw too much heater current for the power tranny. JJ 6V6's are probably pretty close anyway in terms of any volume difference you might get.

    Check your bias current and plate voltages as a starting point. Check all your preamp tubes next. After that, you'll need to look further into the guts. The electrolytic caps for filtering and/or bypass may be going or gone. Bypass caps in particular would be the next place I'd look if you are not having any hum problems (that would be due to bad filter caps.)
     
  5. Phyllo

    Phyllo Member

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    Thanks guys. I thought about turning up bass and treble after I posted. I normally keep 'em pretty low - I'll try that first. If no luck with that, I guess it's off to the tech to get it checked out.
     
  6. sliberty

    sliberty Member

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    My Princeton is a homebrew, but it is pretty true to the original - except that I addad a bit of a mid boost. The standard 6.8k mid resistor didn't provide enough punch for my taste. So I upped it to 15k, and also attached another 10k resistor to a switch. When the switch is engaged, both resistors are in circuit in series, so 25k total. With that much mid, the overall gain of the amp is increased nicely. It's still no Marshall, but it helps a lot.
     
  7. orogeny

    orogeny Supporting Member

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    when I use JJs, it's because they give me MORE headroom. try a different set of tubes. . . ole groove tubes should be a SIGNIFICANT difference. don't go running to a tech just yet. . . just try changing the lightbulbs. . .
     
  8. Phyllo

    Phyllo Member

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    Thanks again, everybody.
    Orogeny, it doesn't get any more basic than changing out the 6v6 - I will definitely try that - never heard that about JJ's and didn't realize it would make that much difference!
     
  9. Wayne

    Wayne Member

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    For fun, with the volume on 8+, try turning the treble and bass all the way up on the amp and use the bridge pickup. Turn the tone knob for that pickup off or just about off. Turn your guitar volume all the way up. The guitar won't be putting out much treble but the amp will make up for a lot of it and the effect should be a fair amount of distortion at a somewhat lower volume.
     

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