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Help on Midifying a pedalboard

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  • Help on Midifying a pedalboard

    Hi! I recently got a pedalboard 27 keys from an old viscount organ. I have here attached some pictures. I never midified anything, so I am looking for some help or tips to make it. Can anyone help me here?


    Thanks from Portugal!

  • #2
    Hi Antonio. Welcome to the forum.
    Having midified a number of pedal boards of all kinds for friends putting together VPOs, I'd like to offer my help.

    Your first job is to examine the key contacts to see what kind they are and whether they can be used. Ideally they will be reed switches but if they are not, it is not that hard to install new ones and I can advise you on that.
    Next job: How are the switches wired? Are they straight parallel wired or are they organized in a matrix? In the latter case you should see isolating diodes.

    Get back to me with that information, and we can take it from there. Photographs are very useful!


    • #3
      Something I have done a few years ago is to find a cheap Personal Keyboard. Yamaha made several models as also did Casio. Found them used for $5 or $10 on Craigslist.
      If they have MIDI out connections in the back, it's a useful midi encoder.
      Simply wire the pedal switches to the keyboard circuit and it never knows the difference.
      Use the MIDI to drive anything you like.
      Sometimes, if you're lucky, the little keyboard will have a nice bass sound, like a plucked bass or even synth bass as part of the deal. Makes for a great free-standing bass pedal unit.
      Haven't done anything like that in 10 or 15 years, but I would imagine it can't be too difficult to find. Lots of solder joints, but you'll have to do that anyway.


      • Coenraads
        Coenraads commented
        Editing a comment
        This is what I did back in the early 1980s. It worked fine if you don't mind ripping into the keyboard. But as suggested, do check for that MIDI out connector. I mounted the whole thing (minus most of the case) out of sight under the two manual keyboards. Those were the good old (pre Arduino) days

    • #4
      Alas, I recognize those contacts, my Wurlitzer has a near identical arrangement (and my Baldwin too, I think). There's a spring mounted into the pcb that is deflected down to meet a bar under each one, which is grounded. Looks like a number of those bars on yours are a little bent. Both should be a nice silvery color, but they're heavily oxidised. There's a little flexing of the spring on overtravel that helps clean up the contact point, but you probably won't find it to be reliable, especially since many MIDI conversion boards don't put much current through the contact, so there's no electrical discharge to help keep the oxidation off.
      I cleaned the contacts on my Wurlitzer using a tiny wire brush, but they're still a little intermittent (not one pedal worked when I got it).
      I'd agree with the suggestion of getting reed switches, which could be glued to the pcb, and magnets glued to the end of the pedal sticks. From the look of the traces on the pcb and the connector used, all the contacts are brought out separately rather than being in a matrix, so you would need to find a converter that works like that, but you're not tied to staying with that arrangement.

      Click image for larger version

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      Allen MDC-42, 301-C, 124, ADC-3100.
      Wurlitzer Omni 6000, Rodgers C-445, Baldwin D-912


      • #5
        All the suggestions here are good. If you want to buy a kit to rewire it, Midi Boutique sells a pedalboard conversion kit. If the pre-existing contacts are intermittent even when clean, then it’s better to go with replacement switches, in my opinion.

        -Current Instruments: Allen Mos-2 225 RTC,1870's W. Bell Reed organ, 1890's Singer Chicago upright grand piano Former Instruments: Yamaha Electone E3R
        -Website: https://www.exercisesincatholicmythology.com


        • #6
          Thanks​ for your PM, but I will answer on the Forum so others can contribute their thoughts and we can all learn from each other.​ You say you have no electrical experience. Unless you know how to solder, some basic electricity and how to use a multimeter, it will be a bit of a steep learning curve. But don't let that discourage you. Can you call on friends or members of a local electronics club to guide you along the way? I'm sure they would be happy to share what they know. Like myself, most of us have learned much from others and are only too happy to share what we have learned along the way.

          1. The contacts: I recall using gold on gold, (Kimber Allen), contacts many years ago on a theatre organ and they worked flawlessly, even with 5 volt switching. But this is an expensive solution.
          I've also tried phosphor bronze and they were nothing but trouble, each playing session being preceded by working all the pedals up and down the keyboard. I replaced them with silver on silver, and these worked fine as long as the pedal was played regularly. Ever since, I have used 1/2 inch reed switches which are both inexpensive and reliable.
          My feeling is that although you can try using the existing switches on your pedal board, I think in the long run, it will pay to replace them with reed switches.

          2. Mounting the reed switches: Reed switches can be operated with the small ceramic magnets available in craft stores. I keep a variety on hand since they cost so little. Hook up a reed switch to a multimeter in continuity checking mode and experiment to get a feel for how these switches work. Remember, the magnetic field lines must be parallel to the reed to activate it so orientation of the magnet is critical. When bending the leads, always hold on to the leads with a small needle nose plier next to the glass before attempting to bend the leads. They are fragile and we've all broken a few.
          You can mount the reed switches so that they are activated by a small magnet glued to the pedal. There are many ways of doing this, so be creative. I have found that adjustments with this "moving magnet" approach can be tricky especially if two notes are played side by side. It helps to alternate the polarity of the magnets on adjacent notes so that they repel each other.
          When we were converting the pedal on a Harrison & Harrison organ from tubular pneumatic to electric, I tried using what I call the "moving shutter" approach and found it to be precise and not at all finicky. I recommend it. You can read about this on my website:

          3. The encoder: I have never used the products of MIDI Boutique, but those on the Forum who have, speak highly of this source for VPO circuits. Their 32 key pedalboard MIDI encoder looks just like what you need and hooking it up would be quite straight forward. If you have programming experience, you can use an Arduino Uno as encoder for considerably less money. The code can be found on my website. But the latter uses matrix wiring and isolating diodes, not recommended when I suggest you keep things as simple as possible.

          ​Please feel free to ask any questions you may have on this Forum​. We want you to be successful!