Vibro Champ - Does Vibe all the Way Down = Vibe Off?

Discussion in 'Amp Central Station' started by Alcohen, May 8, 2021.

  1. Alcohen

    Alcohen Tele-Meister

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    I have a '65 Vibro Champ that didn't come with a pedal. I've always just kept the vibro intensity pot all the way to 0 when I wanted it straight. Is that the same as having the circuit off via a switch? Or is the circuit still in play somehow with the pot at 0?
     
  2. Lowerleftcoast

    Lowerleftcoast Friend of Leo's

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    It is still in play. You would need the foot switch or a shorting plug to turn it *off*.
     
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  3. Boreas

    Boreas Friend of Leo's Silver Supporter

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  4. Alcohen

    Alcohen Tele-Meister

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  5. corliss1

    corliss1 Friend of Leo's Platinum Supporter

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    In most amps, the plug turns it on. In the Vibro Champ, the plug completes the circuit to ground, shutting it off.

    http://fenderguru.com/wp-content/uploads/2015/04/vibrochamp-schematic.jpg

    The Intensity control all the way "off" shorts the signal coming out of the trem section. The footswitch kills the oscillating section, keeping the effect from happening, no matter where the Intensity control is set.
     
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  6. scook

    scook Tele-Meister Silver Supporter

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    Not a direct answer to your question but my SF VC didn’t come with a footswitch. I got a replacement from Mojotone that looks and works perfectly fine. I’d highly recommend just getting a replacement footswitch.
     
  7. Boreas

    Boreas Friend of Leo's Silver Supporter

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    Duh... I guess you are right!!
     
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  8. J. Bonkosky

    J. Bonkosky Tele-Holic Silver Supporter

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    The tremolo circuit always will have an effect on the preamp if the depth is above zero. Even with the footswitch set to off. Think of it as a crappy tone control.
     
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  9. Willie Johnson

    Willie Johnson Tele-Afflicted

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    Have any of you guys done the tremolo mod with the SPST pot that clicks off the tremolo? What did it do to the amp's overall gain when clicked off? Curious about this for my SF Princeton--I put a shorted RCA jack in the trem switch input as an experiment but doesn't do anything different than turning both pots down.
     
  10. Alcohen

    Alcohen Tele-Meister

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    Could you explain this? What effect? And if you turn the Depth control to 0 rather than the Intensity pot (which, of course, is what I've been doing), does that remove the effect from the circuit?
     
  11. Paul G.

    Paul G. Friend of Leo's

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    If you had an oscilloscope, you would see that regardless of pot positions or switch position, the tremolo is always on. Always.
     
  12. fiveightandten

    fiveightandten TDPRI Member

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    I have a SPST on a pull pot for the intensity knob on my BF Deluxe. It just grounds the trem circuit in the exact place that the foot switch does. There is no audible difference in the gain on my amp when clicked on vs. off.
     
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