Fender Custom 68 Pro Reverb question

Discussion in 'Amp Input - Normal or Bright' started by EC Strat, Jul 21, 2021.

  1. EC Strat

    EC Strat Senior Stratmaster Gold Supporting Member

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    Been eyeing one of these. They sound really really really good - does anyone know about it’s extension Jack? It comes with an 8 ohm speaker, can the transformer handle a 2x12 4 ohm load?
     
  2. Antstrat

    Antstrat Most Honored Senior Member

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  3. Stevem

    Stevem Senior Stratmaster

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    The extension jack is just wired in parallel with the main jack and in fact is wired as a safety.
    It does not work unless the main speaker jack is used also , so if no speakers are plugged in there is a intentional short across the output transformer so no harm will come to it from having no speaker load on it.

    The amps output transformer only has a 8 ohm winding so if you plug in two 8 ohm speakers the amp will output 33 % less wattage with that 4 ohm load then with a 8 ohm load, also the amps output tubes will last 33% less due to other technical factors!

    You will get earlier distortion from the 6V6s with a 4 ohm load if that's what your looking for .

    If your looking for more clean head room out of the amp and want to run two 8 ohm Speakers for a 4 ohm load then the amps output transformer needs to be replaced with one with a 4 and 8 ohm winding.

    To sum up, to make up and exceed that 33% drop in wattage and get a volume increase from running a 4 ohm load you would need to run two 16 ohm speakers in parallel into that extension jack.

    Another thing you can do is to not use the amps 8 ohm speaker at all and just run it into a cabinet with two 16 ohm speakers wired in parallel.
    That will get you all of the amps 22 watts and then double the sound pressure level to your ears!
     
    Last edited: Jul 22, 2021
  4. EC Strat

    EC Strat Senior Stratmaster Gold Supporting Member

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  5. RandyM

    RandyM Strat-Talker

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    Not to question your reply, but the Custom Pro has 6L6 (not 6V6), correct? And not 22 watt, but around 40 watts?
     
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  6. atomicmoondog

    atomicmoondog Strat-Talker

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    “EXTERNAL SPEAKER: Allows external speaker use in parallel with internal 8 ohm speaker. External speaker must be rated at 8 ohm; output automatically switches to 4 ohm when external speaker is connected.”

    I run mine with external 8 ohm speaker cabinets all the time. Glorious!
     
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  7. EC Strat

    EC Strat Senior Stratmaster Gold Supporting Member

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    Yeah he’s thinking it’s a deluxe reverb
     
  8. EC Strat

    EC Strat Senior Stratmaster Gold Supporting Member

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    I bet! I’m GASing hard for this amp. Do you happen to have an ext cab that fits the width and matches the tolex / silver face look? I was looking into mojotones offerings
     
  9. atomicmoondog

    atomicmoondog Strat-Talker

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    Mojotone makes great cabinets.
    Actually, I have a couple of V Boutique cabinets with EVM-12L speakers in each. No, they don’t match but they stack nicely.
    I also use a cabinet with a alnico cream speaker, and it sounds awesome as well.
    The 68 Custom Pro Reverb is just a really great amp.
     
  10. Stevem

    Stevem Senior Stratmaster

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    Sorry, yes reading the post and seeing 6V6 made me think DR and not PR.
     
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  11. EC Strat

    EC Strat Senior Stratmaster Gold Supporting Member

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    I was wondering how the Cream or Gold would sound in the pro reverb.