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Turning on a farfisa compact duo without the power supply

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  • Turning on a farfisa compact duo without the power supply

    Hey guys, I just acquired a farfisa compact duo and don’t have the power supply. I want to turn it on to see if it even works. Does anyone have any ways of doing this? I’ve read a couple other threads on here but I’m a little confused. Could I power it with a 24volt dc positive power supply? This is what I’d plug it in to on the back of the organ, there’s no cable coming out of the bottom. I think this unit was maybe modded.

  • #2
    The 24V supply is only for the circuits inside the F/AR power supply. It gets regulated down to 9V by a Zener diode inside the organ, so you really need a 9V DC supply, preferably regulated.

    In stock form, the organ gets two separate power supplies from the F/AR, the DC supply and a 9VAC supply that supplies things like the lamps in the front strip, the knee pedal, and the volume pedal.

    The DC supply powers the tone generator boards and the audio circuits.

    Of course, if it's modded, there's no telling what someone did to it inside.
    I'm David. 'Dave' is someone else's name.

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    • #3
      Originally posted by David Anderson View Post
      The 24V supply is only for the circuits inside the F/AR power supply. It gets regulated down to 9V by a Zener diode inside the organ, so you really need a 9V DC supply, preferably regulated.

      In stock form, the organ gets two separate power supplies from the F/AR, the DC supply and a 9VAC supply that supplies things like the lamps in the front strip, the knee pedal, and the volume pedal.

      The DC supply powers the tone generator boards and the audio circuits.

      Of course, if it's modded, there's no telling what someone did to it inside.
      Thank you for the answer Dave! So would a regular 9 volt dc center negative that I use for pedals work?

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      • #4
        Originally posted by Ifudontlikebees View Post

        Thank you for the answer Dave! So would a regular 9 volt dc center negative that I use for pedals work?
        The Duo did not originally have a barrel connector on it, so there's no way for me to know how it's wired, nor do I know whether or not your supply is regulated.

        I'm guessing your supply is a Boss unit. Most power supplies are actually wired center positive with a negative barrel, but Roland decided to be different. If there's no documentation, you'll have to open it up to see how it's wired.
        I'm David. 'Dave' is someone else's name.

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        • #5
          Thank you. It’s a snark 9 volt dc center negative power supply. Not sure if it’s regulated unfortunately.

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          • #6
            Also there is a black red and ground wire coming from the barrel connector if that means anything!

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            • #7
              All I know is that someone added a power connector to this Duo. I haven't the faintest idea how it might be connected inside because it's not stock. I don't know what kind of power supply the person had who installed it or what its polarity was. It's in your possession, so the job of figuring all that out is up to you.
              I'm David. 'Dave' is someone else's name.

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              • #8
                Well, I plugged in my power supply and it turned on! Didn’t turn on the lights and of course it didn’t turn on the reverb but the organ is playable. Thank you for the help!!

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                • #9
                  Originally posted by Ifudontlikebees View Post
                  Well, I plugged in my power supply and it turned on! Didn’t turn on the lights and of course it didn’t turn on the reverb but the organ is playable. Thank you for the help!!
                  In the Compact Duo the reverb pan and and all the preamp circuits are not inside the organ, but inside the F/AR unit.
                  The "Reverb" tab it's just a switch that shunt the reverb signal to ground.

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