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68 Custom Princeton Reverb Schematic?

Discussion in 'Amp Central Station' started by =JL=, Aug 20, 2014.

  1. =JL=

    =JL= Tele-Meister

    122
    Apr 1, 2010
    Wales, UK
    Hi, does anyone know where I can find one of these? I have the 65 PRRI schematic but would like one for my 68 Custom.

    It's the only new Fender amp I've ever bought which didn't come with one, and the Support page on the Fender site doesn't have them.

    I know there are only a few detail differences between my amp and the PRRI, but I'd like to know exactly what they are.
     

  2. t-luxe

    t-luxe Tele-Afflicted

    Nov 23, 2009
    so. cal
    I got one for my Custom Deluxe Reverb from Fender Customer Relations.
    The link is on Fender's Website, bottom of page.
     
    Last edited: Aug 20, 2014

  3. =JL=

    =JL= Tele-Meister

    122
    Apr 1, 2010
    Wales, UK
    I'll email them now, thanks!
     

  4. pinkphiloyd

    pinkphiloyd TDPRI Member

    Age:
    41
    33
    Jul 6, 2010
    Ft. Smith Arkansas
    Did you have any luck? I'd like to have a copy of this, myself.
     

  5. jhundt

    jhundt Poster Extraordinaire

    Age:
    64
    Mar 23, 2003
    Netherlands
    if anyone's got it - please post it!
     

  6. =JL=

    =JL= Tele-Meister

    122
    Apr 1, 2010
    Wales, UK
    I did get it, but unfortunately the file is too big to attach here.
    Email Jeff Bielke at Fender.
    jbielke@ fender.com
     

  7. pinkphiloyd

    pinkphiloyd TDPRI Member

    Age:
    41
    33
    Jul 6, 2010
    Ft. Smith Arkansas
    Will do, thanks.
     

  8. waparker4

    waparker4 Doctor of Teleocity Ad Free Member

    Nov 9, 2011
    Philadelphia, PA
    Interesting, that extra 18k "minimum bass" resistor. Seems rather pointless.
     

  9. jhundt

    jhundt Poster Extraordinaire

    Age:
    64
    Mar 23, 2003
    Netherlands
    thanks King! I have been wondering about this for a while.

    waparker mentions the 18k bass resistor. Other than that I found only 3 minor changes in my first quick look-see:
    1) bottom cap in the tone stack was .047, becomes .022
    2) inline resistor on reverb return was 470k, becomes 1M
    3) NFB resistor was 2.7k, becomes 5.6k

    but people are saying this amp has a whole different sound and character from the 65 PRRI.
     

  10. =JL=

    =JL= Tele-Meister

    122
    Apr 1, 2010
    Wales, UK
    It sort of does, and that's mainly caused by the Bassman/Marshall midrange values, but it's still unmistakably a Princeton sound.
    I converted mine to PRRI spec out of curiosity, and speaker aside, it's not a hugely different sounding amp.
     

  11. Wally

    Wally Telefied Ad Free Member

    Mar 17, 2003
    Lubbock, TX
    FWiw, one could take the PRRI and modify channel one to have a much 'tweedier' sound than the '68 Custom Pricneton REv will yield out of that channel, ime. Better than that is to get a SF Princeton Reverb....and the mods are much easier to do and can be taken even further. Fender could have marketed a much different amp...but they will sell a lot of these because the marketing literature is a good read, right?
     

  12. =JL=

    =JL= Tele-Meister

    122
    Apr 1, 2010
    Wales, UK
    They'll sell a lot of them because they sound good, and having modded mine back and forth between the two specs the '68 Custom is a slightly more usable general purpose amp for me, although still unmistakably a Princeton.

    It's not just marketing hype, they really do work better with a greater range of overdrive pedals than the 65.

    Princetons only have one channel by the way so yes, that probably is the best one to mod.
    :)
     

  13. TriumphTune

    TriumphTune NEW MEMBER!

    2
    Sep 30, 2009
    Athens, GA
    Sorry to ressurect this thread, but I was wanting to ask you JL, since you converted your 68 to Prri spec, did the extra bass go away and did the reverb come back to the prri levels?

    Thanks again?
     

  14. TriumphTune

    TriumphTune NEW MEMBER!

    2
    Sep 30, 2009
    Athens, GA

  15. =JL=

    =JL= Tele-Meister

    122
    Apr 1, 2010
    Wales, UK
    No, it made no difference to actual bass or reverb levels, though the perceived level of bass went up slightly because I was essentially scooping the midrange a little.
    As mentioned in another thread around here somewhere I controlled bass and reverb levels in one cheap move, I changed V3 to a 12AY7.
     

  16. keithb7

    keithb7 Friend of Leo's

    Age:
    47
    Jan 9, 2010
    Western Canada
    The negative feedback resistor value at 5.6k (R10) is up from 2.7k. Just so I understand, a larger value resistor means less signal from the OT is allowed back into the preamp circuit. Allowing less signal back in, means earlier onset of break up. Correct?

    A person could insert a switch to tun off feedback completely for more break up if wanted?
     

  17. waparker4

    waparker4 Doctor of Teleocity Ad Free Member

    Nov 9, 2011
    Philadelphia, PA
    Yeah. The switch would just cut the connection (open)
     

  18. barker

    barker Tele-Meister

    478
    Jan 9, 2014
    Nashville, TN
    Just curious, how does the in-line reverb resistor affect the tone of the reverb? I'm assuming the reverb is brighter using the 65 Princeton resistor value. Is that true?
     

  19. bradpdx

    bradpdx Friend of Leo's

    Jul 16, 2006
    Portland, OR

    Nope. Changing that resistor only alters the maximum volume of the reverb. On the CPR, the max volume is reduced a bit from the original.

    Nothing is done to alter reverb EQ.
     

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