Paul C and Stokes mod

Discussion in 'Amps and Cabs' started by silver surfer, Feb 15, 2008.

  1. pula58

    pula58 Silver Supporting Member

    Messages:
    1,705
    Joined:
    Jan 2, 2007
    Location:
    Pacific Northwest
    I did both the stokes and the changed bias on the PI ("paulC"). I liked the changes, The stokes gave me more clean headroom. It was very noticeable.
     
  2. traynor_garnet

    traynor_garnet Member

    Messages:
    2,751
    Joined:
    Jan 12, 2004
    Location:
    Canada
    I have a SF Princeton (Nonreverb). Will the Paul C mod give me more gain and a bit more volume? Or, is it only applicable to the Princeton Reverb ?

    I am looking to get "more" out of the amp but don't want to fundamentally change it or make it something it is not.

    TG
     
  3. mark norwine

    mark norwine Member

    Messages:
    17,119
    Joined:
    Jul 25, 2005
    Location:
    NJ...GSP135


    Nowhere in the Fender BF lineup is there more disparity between rev & non-rev models than with the Princ. & PrincRev. Because of the lack of reverb, your amp lacks a recovery stage and, as such, a lot of gain.

    IMO, your amp "is what it is" and neither mod discussed herein (PaulC or Stokes) will do anything of significance to change that.

    There *IS* a way to get a non-rev princ. to come alive, but it's an invasive mod [sacrifice the trem in order to make a LTP inverter], but you said:


    Getting more without changing it isn't going to happen. As I said before in this thread,
     
  4. Gris

    Gris Member

    Messages:
    393
    Joined:
    Oct 9, 2008
    Location:
    Paradise Beach ... :-)
    I have a BF non verb Prince and it is my fave above all the others - brown, black, verb, non-verb, etc. (except one other modded PR i had). It has an Allen TO20 and a 12" spkr, as well as a diff filter section. Also removed the resistor from the back of the bass pot and put another 'mid/raw' pot in the ext spkr hole in back. No drilling required, all easy stuff and the amp is super versatile and screams... :)
     
  5. Paulmc

    Paulmc Member

    Messages:
    4
    Joined:
    Aug 14, 2018
    Gris, your inbox is full.
    I have a 78 Fender Princeton non reverb. I've rebuilt the eyelet board and got a new cap can. Would you be able to explain how to get more gain from the amp please? Its clean all the way to 10 on the volume. Cheers Paul
     
  6. macmax77

    macmax77 Supporting Member

    Messages:
    12,137
    Joined:
    Oct 24, 2005
    Location:
    Pembroke pines-Santiago-Greenville
    This is such a great thread for me, I do not understand s ^&*.

    And yes, I am eating and just wanted to share my hurt feelings.
     
  7. dcbc

    dcbc Member

    Messages:
    1,995
    Joined:
    Mar 8, 2013
    Location:
    Texas
    David Allen did the phase inverter mod to my old 76 PR and got rid of that rasp/ratty distortion. I thought it sounded absolutely fantastic. I don't own the amp anymore, but my friend who is its current owner can't say enough wonderful things. No reported ill effects from the mod several years later.
     
  8. HotBluePlates

    HotBluePlates Member

    Messages:
    7,272
    Joined:
    Mar 27, 2017
    That person hasn't logged in since 2015. Such are the dangers of reviving a necro-thread to ask someone questions...
     
  9. Paulmc

    Paulmc Member

    Messages:
    4
    Joined:
    Aug 14, 2018
    Oh sorry.
    Was looking for help getting some more gain out of my princeton.
     
  10. HotBluePlates

    HotBluePlates Member

    Messages:
    7,272
    Joined:
    Mar 27, 2017
    Can you tolerate more midrange?

    If yes, look at the Bass pot. There is a 6.8kΩ resistor soldered to it running to ground. Replace that resistor with a pot between 25kΩ to 250kΩ (wired as a rheostat; use one lug grounded, and the wiper).

    If you go for a 250kΩ pot, turning the pot to max will isolate the tone circuit from ground, boost mids a lot, and increase overall signal level to drive the output section. You might expect a ~20dB signal boost.

    You could mess with a master volume, but you're not likely to get great distortion from the Princeton's phase inverter anyway.

    If you need more gain/distortion than the above provides, you really want a different amp with a different preamp & phase inverter architecture.

    _____________
    EDIT: All I did here was describe the Allen Amps "Raw" control, meantioned earlier in this thread.
     
    Last edited: Aug 14, 2018
    apalazzolo likes this.
  11. Jeff Gehring

    Jeff Gehring Silver Supporting Member

    Messages:
    5,166
    Joined:
    Jan 17, 2008
    Location:
    Kansas City area
    You know, it may be heresy, but the Princeton I liked the most was a modified one I rebuilt for a customer with a long tail PI (courtesy of giving up the tremolo tube). Kept the tremolo in the amp by adding a MOSFET tremolo, a la RG Keen. To me, it sounded more like a "little big amp" with the long tail PI rather than sounding like a "little amp" with the cathodyne. To be fair, though, we also replaced the power transformer with David Allens excellent TP25...
     
  12. Paulmc

    Paulmc Member

    Messages:
    4
    Joined:
    Aug 14, 2018
    Thanks for the info, thats great. Im building a 5e3 next so will probably keep my princeton clean as you recommend. Is the 6g2 similar sounding to the 5e3? Cheers Paul
     
  13. Paulmc

    Paulmc Member

    Messages:
    4
    Joined:
    Aug 14, 2018
    Jeff. Is there a layout diagram for the long tail PI mod?
     
  14. hasserl

    hasserl Member

    Messages:
    4,719
    Joined:
    Oct 24, 2004
    Location:
    So Cal
    Hey guys, just came across this old thread in a google search. FYI, my old PR with the Stokes mod is still doing fine, with the original power transformer, and it gets quite a bit of use. I regularly put it on the backline of a jam I host, and for 4 hours it hardly gets a rest. Great amp, sounds fantastic! I don't doubt Mark has replaced some power transformers, just saying what my experience has been on my own personal amp. It already had the Stokes mod done years before this thread started, and that was over 10 years ago. The power transformers are small, but maybe not as delicate as they would appear to be.
     
  15. JDW3

    JDW3 Member

    Messages:
    3,634
    Joined:
    Mar 2, 2005
    Location:
    Below Flint
    OMG, has it been 12 years...?

    With all the fear of blowing transformers, I stopped using my modded Princeton...about 12 years ago.

    About 13 years ago I installed the Stokes mod, and the LTP.

    My tastes changed, I don't run my amps quite so loud, and began using pedals again. What to use for a pedal platform thats easy to carry?

    I pull the old Princeton out, and its absolutely killer. The amp already had a mid control in place when I bought it. So its all usable guitar frequencies. Even running it really hard, the transformers aren't really hot. No worries.

    Theres also no bass flub which is nice. I'm using a Weber F150T. It might be close to broken in now. 8)
     
    TAWeber likes this.

Share This Page

  1. This site uses cookies to help personalise content, tailor your experience and to keep you logged in if you register.
    By continuing to use this site, you are consenting to our use of cookies.
    Dismiss Notice