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Morley PFV Volume Phaser circuit question

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  • Morley PFV Volume Phaser circuit question

    I've just resurrected a classic Morley Phase Shifter - great optical circuit.
    While I was able to find a basically readable schematic the circuit has five trimmers in it and I can't find any documentation on either the preferred settings or adjustment procedure.
    According to the schematic at Shematic Heaven for the PFV they are:
    1 - LFO output adjustment the actual name is unreadable)
    2 - Lamp Bias
    3 - "Unreadable" Lamp
    4 - Mixer (Wet/Dry) in Phaser Circuit
    5 - Harmonic trim

    Aside from the Lamp Bias, which I set so that the lamp worked measured by the Mk 1 eyeball setting, the others I set centered.
    The pedal works and sounds great
    But I'm sure that with the correct settings it would sound and work even better.
    Anyone know where I could locate, or who might have the settings for the circuit?


  • #2
    Originally posted by Saransk93 View Post
    ......While I was able to find a basically readable schematic......
    Why not post it?
    "Yeah, well, you know, that's just, like, your opinion, man."


    • #3
      Here is a cleaned up but still not very readable schematic and instructions and what appears to be a re-draw of same. I notice there is a capacitor missing at the input transistor collector in the re-draw.
      I can't answer the original question though it looks like some of the trimmers set the limits for some of the controls.
      Attached Files


      • #4
        This is the documentation I have - but the schematic is clearer for the "official" one.
        You'll notice that the Pro-Phaser (#3) is slightly different than the Phaser - Volume (#1)
        #1 has the volume circuit lamp (the LDR appears to be missing)
        The location in the circuit, and what they are called, of a couple of trimmers is different as well.
        I fell that the setting of the LFO output trimmer, as well as the trimmer for the Lamp Bias would be better if I could set them correctly.

        Somewhere there is a set of instructions with either measurements or settings for the various trimmers


        • #5
          Here is my re-draw of the control circuit and trimmer locations. Not sure if I'm 100% correct. If you can, post some closeups of the board from various angles including under the cardboard shield in the middle.

          Attached Files
          Last edited by dmeek; 11-08-2019, 10:02 PM.