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  • Keying voltages / system on Allen ADC Organs



    The fun never stops here! I'm curious if anyone could comment on the keying used on Allen's ADC organs. I'm getting ready to order a ton of MIDI hardware for the Carillon Americana, but I got to thinking that if I could just wire input boards from the Artisan system onto the keying voltages inside the organ, it would be cheaper in the long run and I could reuse the boards if I ever got a separate console for the carillon (which is a likely possibility in the future).</p>

    So, with that in mind, I presume the ADC series are keyed with constant voltages and are not connected at all to the tone generation system? If anyone could comment further and happens to have voltage specs it would be most appreciated! [:)]</p>


    </p>

    Thanks!
    </p>
    Corey

    Allen MDS-41-S with MIDI-DIVISION-II
    Schulmerich Carillon Americana - 61 notes Flemish / Harp / Celesta / Quadra / Minor Tierce
    - MIDI Retrofit finally underway & Moller console in need of refurbishment
    Schulmerich Campanile Digital Carillon (Cast & Harp)

  • #2
    Re: Keying voltages / system on Allen ADC Organs



    I'm sure someone will be able to elaborate - well, no, actually I'm not sure. But short of just rewiring every reed switch yerself - which would hose the organ's TG system - this isn't going to be easy. IIRC there is a custom shaped PCB or PCBs along the back of each keyboard, that immediately encode a matrixed signal for the multiplexer. Now the stops on an ADC are in a traditional 1-1 wiring. But I remember trying to "manually key" my ADC organ, and getting horrible discordant combinations of notes. I seem to recall "Classic Organ Works" (?) telling me nobody they knew had figured out how it worked to reverse engineer it. (They said it was not, to their knowledge, one of the "industry standard" schemes.) Not to say the right person couldn't! So, good luck with that...</p>

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    </p>

    </p>

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    • #3
      Re: Keying voltages / system on Allen ADC Organs



      IIRC, the keying on the ADC organs is directly multiplexed (scanned) at the key contacts, so there is no "keying voltage" per se. It would be like all the C contacts are in parallel (thru diodes), all C#'s, D's, etc. The other side of the key contacts would be strobe busses, likely by octaves (i.e., strobe 1 would be octave 1, strobe 2 would be octave 2, etc.).</P>


      No easy way to get to a voltage for each key unless you want to decode their mux (multiplex) system, which would not be hard to do if you are (digitally) electronically knowledgeable. It's just a messy bread-board job because of the large number of IC's involved. Harrison Labs (they advertise on eBay all the time) might have something that does this).</P>


      Toodles.</P>
      <P mce_keep="true"></P>

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      • #4
        Re: Keying voltages / system on Allen ADC Organs



        Chris,</P>


        I hope you'll find a friendly tech or dealer to order you a MIDI adapter from Allen. The ADC keying system is a diode matrix but, as mentioned above, there is no constant voltage, but some kind of scanning going on. Any tampering with the system at the key contacts would certainly bring the system down and then you'd have a dead organ!</P>


        The MIDI board will send out ordinary note-on note-off data on separate channels for the 3 manuals and pedalboard, which should interface perfectly with the carillon keyers you are wanting to attach.</P>


        John</P>
        <P mce_keep="true"></P>
        John
        ----------
        *** Please post your questions about technical service or repair matters ON THE FORUM. Do not send your questions to me or another member by private message. Information shared is for the benefit of the entire organ community, but other folks will not be helped by information we exchange in private messages!

        https://www.facebook.com/pages/Birds...97551893588434

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        • #5
          Re: Keying voltages / system on Allen ADC Organs



          Thanks to everyone for the responses - I had suspected that this was the case, but figured it would be worth checking for sure. I just generally prefer to innovate with my projects so that if I make changes in the future, that I can reuse most if not everything purchased.</p>

          The plot thickens, as I don't really have a lot of room for a second console in the house, but I'm seriously questioning whether I will ever be able to find enough stop brackets to properly switch the carillon stops (not to mention what they might cost). It may actually be cheaper, easier, and allow more flexibility in the future to have a separate console. Not to mention some of my feelings are hinging on the fact that I may have a possible lead on an original Schulmerich console. Only time will tell if it really is a large system or not.
          </p>

          The output of the Allen MIDI board will be usable along with the Relay section of my MIDI system to provide proper data if I decide to go that route.
          </p>
          Corey

          Allen MDS-41-S with MIDI-DIVISION-II
          Schulmerich Carillon Americana - 61 notes Flemish / Harp / Celesta / Quadra / Minor Tierce
          - MIDI Retrofit finally underway & Moller console in need of refurbishment
          Schulmerich Campanile Digital Carillon (Cast & Harp)

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