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  • Encoder vs Keyboards

    I want to build a VPO and had thought of starting from scratch with an old organ case but have not been able to find one nearby. Thus, I will bring my 50-year-old Schoeber Recital organ (dividers, bussed) that I built into the 21 st century. I have a key decision to make: 1 - find a MIDI controller and use the existing keyboards and switches (much rewiring) or 2 - Rip out the old keyboards and replace them with 61 note MIDI keyboard/controllers (much woodwork and emotional pain.) I have been looking at parts for each path and found the midi kits Two 61 note + 32 encoder, and the M-audio Keystation 61 (I presently am testing hauptwerk and grand orgue with this.) Are there any other useful available products I missed? I am surprised that there are so few encoders that I have found. Thanks!
    Last edited by Steve Baer; 03-30-2021, 07:03 AM.

  • #2
    A number of forum members report they have built their own encoders using Arduino boards. I don't know the first thing about that stuff, but some of these guys and gals are creating complete MIDI interfaces for their consoles for not much money. I happened to have a pretty old but still decent console encoder from the mid-90's that I pressed into service on my VPO project. It works just fine, but I am discovering a few quirks about it as I go along.

    But for a modern ready-to-use solution, there are suppliers you can find on the internet, such as MIDIBoutique-dot-com and midi-hardware-dot-com (both in Europe) and Artisan (USA) and Classic MIDI Works (Canada). I'm sure there are others as well, but not as many as you might expect.

    In casually looking online for 61-note keyboards recently, I found that there are a half-dozen or so plain-vanilla 61-note keyboards similar to the M-Audio Keystation, for around the same price. They are all different in some ways, and you'd have to read up on them to see if one is better than another for your use. For example, some appear to have flat-front "piano" style keys, while others have the more usual "organ-style" keys with an overhang. I'm sure they differ in a lot of other ways.

    I would guess that most, if not all, such units can be removed from their cases and mounted directly into your old organ console quite neatly, though I don't know that for a fact. Perhaps someone here can verify.

    An option you might consider, rather than gutting the Schober, would be to build or buy a simple "organ desk" to hold the keyboards in the correct position. Many such desks are available (see the Classic MIDI Works site for an example), and these ready-made units hold your keys, provide shelves on which to set your touch-screen monitor(s), have an area designed to receive a standard AGO pedal board, and even a place to mount a music rack. These are essentially a bare-bones substitute for an actual organ console, with the advantage of being extremely easy to move around. Some old organ consoles are so heavy and big, people have trouble getting them into their houses through standard doorways.
    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

    Comment


    • #3
      John: Thanks very much! I will research those sources. I do prefer to use a full organ case. Steve

      Comment


      • #4
        I used encoders from DTS Midi Systems, you can order them direct of from Arndt Organ Supply. I got my from Arndt. He included the Molex style plugs that allowed me to punch down my wires. As your manuals are bussed, it's as simple as connecting one connector per key to the board + the ground, then you use DIP switches to set the midi channel, supply power (12 volts, if I remember correctly) and you're off and running.

        This picture shows the boards installed and wired on the left and right, one per manual. Ironically, in the middle is the board from a pre-midi-fied Fatar Manual that I added to my console as a third.

        Click image for larger version

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        Mark
        At Church: Allen MDS-15
        At Home: 3 Manual Hauptwerk VPO

        Comment


        • Steve Baer
          Steve Baer commented
          Editing a comment
          Mark: Again - Very nice work and pictures! I have around 200 wires to find and solder. I'm still tracing easy access locations from schematics.

      • #5
        Mark, John: Thanks very much! I am working on the paper design. Today I will check the Schober schematics to see how they key the busses. Hopefully, it will be as easy as you show.
        I spent yesterday searching the Forum and internet for encoders and came up with 9 possible sources, including DTS. They were my second choice. I think at the moment I will go with Midikits in my paper design due to their lower cost and very complete online documentation, including schematics.
        My next goal is to pick a small computer like an NUC: Linux vs Windows? Fanless? Always on or fast boot-up?. Any ideas? THANKS Steve

        Comment


        • #6
          Thanks for all the help. My paper design is finished and today I started ordering parts:

          - Midikit 3 x 61 plus 32 Keyboard and pedal encoder board - $104.04 from midikits.net, incl all shipping and other costs.
          - AcePc Fanless Mini PC 8 Gb RAM & 120 GB SSD - $203.29 incl all costs from Amazon. This has a free return option.
          - Software will be GO
          - Case, keyboards and pedals will be my 50-year-old Schober Recital organ.

          If the PC does not have enough power I will exchange it with the i5 machine that currently controls my ham radio station.

          I'm going to do future progress reports in the VPO thread.
          Cheers,

          Comment


          • #7
            Interesting. Midi-kits.net is basically selling you a pre-programmed arduino mega with two wires soldered to a midi plug. That’s basically exactly what I posted on my Arduino hub page for a lot less money.

            https://create.arduino.cc/projecthub...ng___&offset=6

            Comment


            • Steve Baer
              Steve Baer commented
              Editing a comment
              It also has a USB port that will plug directly into the computer. The downside of all this is that I have to do 5X61 into 8x8 encoding. The easiest way at the moment seems to be to cut one bus into 8 parts.
              P.S. I'll wear HV gloves around the 5V. Thanks!

            • Admin
              Admin commented
              Editing a comment
              There are keyboard encoders that do not require a matrix configuration known as scan row encoders.
              https://www.midiboutique.com/MIDI-Encoders/mkcv128sn

            • OrganNovice
              OrganNovice commented
              Editing a comment
              Hello Larason2. I'm interested in your Harrison Labs 3 channel Midi encoder for Allen organs but can't seem to figure out how to respond to your classified add. I'm a novice to the Organ Forum Blog so I hope you can help me figure out how to properly post replies. Thanks for your patience and I hope you can get back with me on my request.

          • #8
            You could also reprogram it to work as a 61x3 or 4 matrix. I plan to release that code on the arduino hub page eventually. If you’re worried about the live contact, you could always wire it to the arduino’s ground yourself.

            Comment


            • #9
              John: Thanks for the tip. I did not notice that device on the midi boutique website. I guess I'm too much of a novice.
              Larason2: I don't see how the Midikets board would have enough pins for 61 x 3. As I understand 8 x 8 takes only 16 pins per manual.

              I'm so happy to be learning new things from you all! THANKS

              Comment


              • #10
                You can use the Mega’s analog pins as digital pins as well, and the mega has 16 analog pins. 54 + 16 = 70. I would save a few analog pins for your expression pedals, but assuming you have 3 expression pedals, (and not counting pins 1 and 2, which is the output and input), you could still have 61 x 4 key switches. You would have to solder a diode to each key switch, but you can get them fairly cheaply.

                Comment


                • #11
                  I got my Arduino clones from https://www.microcenter.com/product/...uino-mega-2560 and they were inexpensive enough to have a separate board for each manual.

                  Comment


                  • sandstone42
                    sandstone42 commented
                    Editing a comment
                    Sorry, no, not offhand. I programmed them myself when I was still going the whole VPO route. I got the idea to use the 2560 MEGAS from this site. https://virtualpipeorgans.wordpress.com/

                  • Larason2
                    Larason2 commented
                    Editing a comment
                    I would say there’s no easy way to convert 1x61 to 8x8. You could program an arduino to do it, but you’d be hard pressed to find one that has enough pins, so you’d have to also get into IO expander boards. Much easier would be to rewrite the arduino to accept 1x61 contacts. I’m planning to release just such a pre-baked code, but it’s not ready yet.

                  • you795a
                    you795a commented
                    Editing a comment
                    https://virtualpipeorgans.wordpress.com/ is good code. I started with that but then I wanted to use MIDI connectors so I found other code.

                • #12
                  Larason2: Thanks for your help. I am now barely smart enough to understand your comment better. Your article describes exactly what I aim to do. The board I bought does indeed look like an off the shelf Mega 2560. But Midikits has done the coding and code loading which I wanted to avoid. I don't mind paying them a modest amount for their labor. You should accelerate availability of your work as a product.

                  The generation of 8 x 8 code from 61 keys closing to a common bus sounds like a homework problem for an MIT student. Unfortunately, I am out of touch with modern digital components. (My first digital project used relays, then 6SN7 dual-triodes. My last project used 923 JK flip flops. Those terms probably don't even exist anymore.) I am scouting component catalogs to see if there are any chips I might try in a breadboard.

                  If I can solve this, I will not have to remove the old keyboards (a mechanically difficult job) to cut and support a bus into 8 parts. Thus, it is worth a bit of research time.

                  Thanks again, Steve

                  Comment


                  • Larason2
                    Larason2 commented
                    Editing a comment
                    The only thing to worry about reprogramming the midi kits board is that they may have flashed the memory, making it impossible to load a new program on. Another approach I have thought of is that if you have multiple busses, you might be able to make the 8x8 work. Some of the older organ keyboards had many busses, and if this is the case for you, you could use a separate bus for every row, and solder the diodes to the switch contacts for the columns. Midi boutique sells the Keymux64 boards, which do exactly what you want, convert 61x1 to 8x8. However, the board requires power, which you may or may not be able to get from your Arduino (depends on the voltage and the board current draw). Getting enough boards would also be more expensive than your Arduino!

                • #13
                  There's a lot of stuff still around with the older digital. The keyboard array board in my Allen MOS-1 organ uses ITT 926-5Ns and ITT 946-5Ns. It is impossible to get data sheets on these anymore by searching online. And those old vacuum tubes are being used in abundance today. Here is an example of a preamp using 6K7s. https://www.parts-express.com/FX-Aud...-Black-230-264

                  Comment


                  • Admin
                    Admin commented
                    Editing a comment
                    I don't believe 926-5N or 946-5N are part numbers for the chip, but rather date or batch codes or possibly a custom part number. I don't have a MOS.-1 organ, but the chips on my MOS-2 KBA are CMOS chips with a prefix of CD on the part number, e.g. CD4073, CD401, CD7404, etc. Sttandard TTL chips are usually prefixed with SN, e.g. SN7404.

                • #14
                  The Schober manuals are Pratt-Read keyboards and the wiring of them is fairly simple. There are individual terminals for each of the 61 keys and 5 busbars for the different footages. I think you'd just have to disconnect all the input note wires and use them as the MIDI note inputs, and disconnect the register busses and connect the 8' bus (not the 2 2/3') to whatever DC would be used to key. A similar process would be done with the pedals, but those are handmade keys. (I'd probably use the 16' bus.)

                  David

                  Comment


                  • Steve Baer
                    Steve Baer commented
                    Editing a comment
                    Thanks all. David - Thanks also for the name of the keyboards.
                    I need 61 closures in an 8 X 8 matrix. The Schober keyboard has 5 separate buses so that would give me only 8 x 5 = 40.
                    My Plan A is cut one of the buses into 8 electrically isolated parts (using spacers and hot glue for mechanical support.) That would easily produce the needed outputs, but requires removing the keyboards..
                    My Plan B is based on visualizing this as a relay matrix using 61 devices per board. I went hunting for devices and found ICs like the Toshiba TBD62083, which contains 8 DMOS devices that can provide the needed closures, like relays. 8 of those devices will handle 61 keys, so I would need 16 devices in all for two manuals. It will require a lot of wiring on my part and may be more expensive than the other solutions, like Plan C - the Midi Boutque board at 140 Euros. (Probably around US $200 delivered) But I believe I can do Plans B and C without removing the keyboards.
                    Nothing is easy, but the thinking part is fun! Cheers,

                  • davidecasteel
                    davidecasteel commented
                    Editing a comment
                    I think you misunderstand how the Pratt-Read keyboards are designed. They have internal wiring that allocates each individual tone (of the 61 input connections) to the 5 busbars according to their pitch register--each tone input appears at 5 different keyswitch positions, appropriate to the register (16', 8', 4', 2 2/3', 2') -- those distributions are built into the keyboard. I recommended that you use the 8' bus to route the keying voltage to the keyboard input terminals because that would simulate just having a contact under the key. As originally designed, all keys depressed transfer audio tones to the 5 busbars, and those combined tones are amplified and applied to the stop registration units for stop control and filtering. Without doing a lot of rewiring of the keyboards themselves (I don't recommend even trying it), the only way to get a one-to-one note closure keying voltage is to put the DC onto the 8' bus and take the key down from the input terminal of that pitch. I don't think chopping up the busbars should be necessary -- just group the wires from the "input" terminals.

                    You should be able to do what I suggest without removing the keyboards -- they were wired with the keyboards in place.

                    The old Schober Organ Orphans site had several articles on converting a Recital Model to MIDI, but that site does not appear to exist any longer. I did not copy the articles dealing with the MIDIfication so cannot offer them.

                    David
                    Last edited by davidecasteel; 04-08-2021, 02:54 PM.

                • #15
                  Thinking about David’s post, his approach makes sense. You can get midi working with minimal rewiring, and the original function of the keyboards would be maintained. The main con is you would need a 61x1 encoder for every manual, and you’ve already ordered an 8x8 encoder. With 5 busses on the manuals, you could do a 5x13 matrix, but that would require a lot more rewiring. If you decide to go this route, however (5x13), I could modify my code to get it to work for you on an Arduino Mega. it’s an easy change. Just make sure your Arduino hasn’t been flashed.

                  Comment


                  • Admin
                    Admin commented
                    Editing a comment
                    I agree. Shoehorning a matrix encoder into a situation where the keyboard isn't wired for one isn't an efficient solution. I suggested possibly using a scan row encoder in post #7.3 and provided a link to one with 128 inputs. That would cover the manuals. For the pedals you could either use the 64 input version, https://www.midiboutique.com/MIDI-Encoders/mpc64up or the 32 pedal board encoder, https://www.midiboutique.com/MIDI-Encoders/mpc32xrs. Inputs not needed for keyboards could be used for stops and pistons. No doubt the DYI MIDI kit solution is far cheaper than purchasing off-the-shelf hardware but that equation changes when one factors in one's time. I realize of course, that the time spent rolling your own solution is part of the enjoyment in achieving a goal. I'm just notating alternatives here for those who don't have the knowledge, skill, time, or desire to go the Arduino programming route.
                    Last edited by Admin; Yesterday, 10:42 AM.

                  • davidecasteel
                    davidecasteel commented
                    Editing a comment
                    Using a 64-input row encoder would allow for handling the 32 pedals and all 32 stops (the Recital Model has 32 stop tablets, each of which controls essentially a switch (it switches ground, but that could be changed).

                  • Steve Baer
                    Steve Baer commented
                    Editing a comment
                    David et al: First - Thanks very much for the name Pratt Read. (By coincidence, they were made only a few hundred miles from here in SC.) I looked them up and note that they were also used in Moog synthesizers (Other coincidence: Bob Moog went to the same High School in NYC that I did - 7 years ahead of me.) There are several videos of the key board internals on You Tube that look very similar to how the Recital boards are constructed using gold springs and busbars. I also studied the schematics, so understand the 61 x 5 keying.

                    That being said, I had in mind a switching scheme like David suggested. I may still test that on 1 input, but the midikits developer felt it would not work. That board wants to see continuity between 8 x 8 pins. I could convert key + or ground into 8 x 8 with my switching IC approach, at the cost of 16 ICs and lots of wiring for 2 manuals.

                    I may still use the scanrow method, but the costs build up rapidly. It and David's method do have the real advantage of not having to remove the keyboards. This is a good puzzle. I'll keep you posted. Thanks again for all the help!!
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