'65 Princeton RI External Speaker

Discussion in 'Amp Central Station' started by Texicaster, Jun 7, 2019.

  1. Texicaster

    Texicaster Tele-Meister

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    ¡Bueno!

    I want to try my 8Ω Eminence Copper Head speaker with my Princeton and am confused on the manuals wording. I don't want to damage speakers or amps... Can just plug the Eminence (it's in a cabinet) to either internal or external?

    I just want to hear the Eminence alone so maybe plug into internal speaker socket...unplugging the stock Jensen?

    Can the amp power two speakers?

    From manual...

    INTERNAL SPEAKER—Plug-in connection for the 8Ω internal speaker. A speaker must always be connected at this jack when the amplifier is ON. A speaker impedance load of 8Ω should be used to avoid distortion or damage to the amplifier. When using only the internal speaker jack, a speaker impedance load of 8ohms (minimum) should be used to avoid distortion or damage to the amplifier.

    EXTERNAL SPEAKER—Plug-in connection for an external speaker. This jack is wired in parallel with the INTERNAL SPEAKER JACK {M} and affects the speaker impedance load. Use 8Ω minimum total. To use the external speaker output, first disconnect the internal speaker. Then connect a 16Ω speaker load (minimum) to the internal speaker jack and another 16Ω speaker load (minimum) the external speaker jack.

    TEX
     
  2. Dacious

    Dacious Poster Extraordinaire

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    To use the external speaker output, first disconnect the internal speaker.

    That's the clue. If your CR is 8 ohms, unplug internal speaker and connect external to the internal speaker jack.

    Don't use a guitar cord.
     
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  3. Texicaster

    Texicaster Tele-Meister

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    Cool!

    Yea I have a 12 ga patch cord.

    Thanks,

    TEX
     
  4. Wally

    Wally Telefied Ad Free Member

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    Just to be clear......use a speaker cable not a ‘patch cable’.
     
  5. Texicaster

    Texicaster Tele-Meister

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    Yes... Thanks!

    I use the wrong term. I bought a speaker cable...

    SO patch cables are like guitar to amp cords right? For effects etc....

    I need to learn more of the basics of electric guitars. I've played them off and on for years and a lot the past couple but still never taught anything...all self discovery and forums etc...

    TEX
     
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  6. Wally

    Wally Telefied Ad Free Member

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    Ime, it is better to use defining terms...speaker cable, instrument cable. Patch cable is rather indefinite term....but it is a widely used term nonetheless. Just as ‘audio cable’, patch cable could mean instrument or speaker cable.
     
  7. zombiwoof

    zombiwoof Tele-Afflicted

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    I find this odd, with a vintage PR you can safely use an 8 ohm ext. speaker along with the internal speaker. Do the reissues have crappy transformers or something that can't tolerate the impedance mis-match?. I am thinking that the stuff in the manual is just Fender covering their butt in case of warranty issues, Fenders have generally tolerated that slight impedance mismatch to a lower impedance.
    Al
     
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  8. schmee

    schmee Poster Extraordinaire

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    You can do that on the old ones. But all the old PR's were a bit marginal on transformers. I've found a mismatch on impedance to work but the lower the wattage of the amp, the dirtier it sounds. For home use it may be great though. But it sounds like Fender decided with this amp it's not good. They want an 8 ohm minimum.
     
  9. Wally

    Wally Telefied Ad Free Member

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    Fender advises...as far as I have read....matched impedances on all of their BF/SF Reissue amps. I am in agreement with that thought..ommv. I prefer matched impedance on any amp...again, Ommv.
     
  10. jimash

    jimash Friend of Leo's

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    I play my '68 custom through an EVM12L in a cab, And it sounds wonderful,and I am sacred to death to plug in the internal at the same time. I used to play my real 1968 Twin with two more 12's at 2 ohms loud. No problem. But I wouldn't want to scare my little Princeton, So caution prevails.
     
  11. Crawldaddy

    Crawldaddy Tele-Meister

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    You can do either of the following:

    1. disconnect internal speaker, and connect the external cabinet (with copperhead inside) to that same speaker out jack using a speaker cable.

    2. leave the internal speaker connected; connect external cabinet (with copperhead inside) to external speaker out jack using a speaker cable.

    Princeton Reverb Reissues are robust enough to handle a 4 ohm load.
     
  12. zombiwoof

    zombiwoof Tele-Afflicted

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    That is what I was saying, if you read the whole thread the problem is that Fender is saying in the manual for his PR that you have to keep an 8ohm load on the amp even with an extension speaker. I think that warning is only there for warranty purposes, and that the RI amps will take the slight impedance mismatch the same as a vintage Fender amp would, but Fender is now advising against that.
    Al
     
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  13. Crawldaddy

    Crawldaddy Tele-Meister

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    Is this a brand new reissue? What's interesting is that I owned a pretty recent reissue (2017?), made in USA, that I ran on 4-ohms using both the 8 ohms internal speaker as well as an extension cabinet with an Eminence Texas Heat also 8 ohms, simultaneously with no issues.

    Correct me if I'm wrong, but as of 2019, pretty much all PRRIs regardless of the 65 or 68 models are made in Mexico; and therefore these amps may have a change in spec?
     
  14. fasteddie42

    fasteddie42 Tele-Holic

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    I thought if you were going to use the "external speaker" often, the safest thing to do is put a 16 om in the combo and a 16 om in the extension to get the recommended 8 om load?
     
  15. fasteddie42

    fasteddie42 Tele-Holic

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    the 68 is MiM, the 65 is actually USA.
     
  16. Crawldaddy

    Crawldaddy Tele-Meister

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    If that is the case, and as the model I owned was the '65, then there should be no issue running the amp at 4 ohms.
     
  17. zombiwoof

    zombiwoof Tele-Afflicted

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    That is my feeling, too. I also don't think it matters which version it is, either one should be able to take the mismatch to 4 ohms.
    Al
     
  18. Wally

    Wally Telefied Ad Free Member

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    What happens when the speaker load is at 50% below the specified output transformer impedance? What happens when the load is twice the impedance of the OT? What happens with a matched load? Those answers are of importance, imo.
    And even then, one is free to do what one wishes to do with those three options. If one had three cabs that were as identical as they could be....say three 1x12 open back cabs with the speakers being identical but for the impedance; then one could run such an amp as this Prin Rev at 4,8, and 16 ohms to make a comparison of what they liked about each load and its effects on the sonics.

    I believe a matched load is the safest and most efficient arrangement. And Because an OT outputs a signal one can not assume that it is working properly. I have never burned an OT down but have had to replace OT’s. The first OT Inhad to have replaced in an amp was making 8 watts of lousy sound when it should have been 26 watts of glory....’59 Bandmaster. That was when I learned about that aspect of damaged OT’s. I haves seen a BFDR making 15 watts and sounding like it should not be turned on...no music to be had. As I understand it, mismatches are not as healthy to the circuit and its components, and the detrimental effects are not necessarily immediate and do not necessarily result in silence.
     
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  19. Garruchal

    Garruchal Tele-Meister

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    I have more experience with PA amps and speakers than with guitar amps. Basically: don't run an amp connected to less impedance than it is rated for. You can run it connected to more impedance though. Doubling the impedance of the speaker halves the wattage of the amp. Running a speaker which is less than the rated impedance causes the amp to overheat. That works until it doesn't.
    The upshot: no; you can't run two 8 ohm speakers simultaneously on a Princeton if you want to treat it well. It might work that way for a little or even a long while, but it is like towing a heavy trailer with a tiny car. Something is being damaged.
     
  20. Wally

    Wally Telefied Ad Free Member

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    Solid state amps..as in those P.A.’s....do not tolerate mismatches to the low side beyond the minimum specified impedance allowable. Tubes amp are different animals. In order to get into those differences, one has to answer the questions I posed earlier.
    In solid state amps, mismatching at lower than the minimum spec’d load will destroy the output section. Higher than the minimum load will decrease the output power.
    In tube amps, a mismatch of 50% to the low side puts the stress on the primary side of the output....mainly the tubes.
    A 100% mismatch to the high side puts the stress on the secondary of the output transformer. The amp operates at its most efficient and safest point with a matched load.
    Ime, I think that the vintage Fender habit of supplying an extension speaker jack in parallel...which allows for that 50% mismatch to the low side...is considered safe...for those vintage amps. I never mismatch to the high side...ommv. I prefer to match the load to the OT’s specs.
    Fwiw, there are some amps with extension jacks that are wired not in parallel but in series. Some MusicMan amps are examples of that approach. One has to think that the designers designed for that mismatch to the high side that the circuit allows.
     
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