'69 question

Discussion in 'Effects, Pedals, Strings & Things' started by jb1911, May 13, 2008.

  1. jb1911

    jb1911 Member

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    The internal trimmer, am I right in assuming that it's the same thing as the one in the AM Sunface? It's for adjusting the voltage to the transistors, right? Can I check the voltage on one leg of a transistor while adjusting the trimmer and set it to 4.5v? That's the ideal starting point according to AM. Then tweek to taste?
     
  2. BobbyRay

    BobbyRay Supporting Member

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    I'd like to know too!
     
  3. jb1911

    jb1911 Member

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  4. tlpruitt

    tlpruitt Member

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    The internal trimmer on the 69 does roughly the same thing as the sun dial on the sun face. It adjusts the voltage for the second transistor.

    The bias knob on the 69 does the same thing as the internal trimmer on the sun face. It is a variable resistor at the input that slightly alters the source impedance to soften the distortion a bit.
     
  5. jb1911

    jb1911 Member

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    AM says the internal trimmer is the same as turning your guitar volume down.
     
  6. tlpruitt

    tlpruitt Member

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    Kinda the same, except the input trimmer on the sun face is acting as a variable resistor and the volume in your guitar is a voltage divider. They both are affecting the signal between the guitar pickup and the first transistor in the fuzz pedal. The effect of turning the trimmer is similar to turning the volume control in very tiny increments, however turning the trimmer all the way down won't cut off the signal completely like a volume control would.

    Check out R.G. Keen's 'The Technology of the Fuzz Face' article at GEO for a great decription of what the different trimmers do:
    http://www.geofex.com/Article_Folders/fuzzface/fftech.htm

    -Tim
     

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