Materials list for DIY project

I've had a bit of trouble finding detailed lists/instructions for what needs to be done to add MIDI to a shell I have for 2 61-note manuals and a 32-note pedal board. I've seen the decoders etc. on MGB, but I'm unsure as to what exactly I would need for this project. I see that there is a Decoder specifically for hauptwerk, and you can buy bundles, but I'm unsure of small details such as how one would hook the pre-existing contacts to this, or if new contacts are needed etc. Any help you can give me would be greatly appreciated.

Thanks,
Alex.

It depends a lot on what your two manuals and pedal board came from, whether they have electrical contacts already or not, how any existing contacts are organized, etc.

Can you be a bit more specific about what you're using?

First test your contacts for reliability. Most church organ consoles use higher voltage for the contact switches, while the modern encoder boards typically use only 5V. Even if the contact were perfect originally, there may be some problems with this lower voltage in terms of contact bounce. Clean them with isopropyl alcohol before testing. Usually the pedal contacts need replacing, and are actually easier to handle using reed switches. For manuals reed switches are not optimal as the keys are too close to each other. If the contacts are fine you can think about how they are arranged, is there a common wire, or there are two independent wires for each key, etc.

For your setup a hwce encoder board from MIDIboutique would be sufficient for the two manuals and the pedals. Depending on your budget, skill level with electronics and soldering, there are plenty of other options. If you tell us more we can offer some more help.

Sorry to be so vague, and possibly misleading. The organ is actually a "Howard Classical Organ" (Model H-600) made by Baldwin in 1986. It's an electronic organ. Coincidentally I got it to start working again when I was trying to find an answer to your questions . . . Still, I'd like to install MIDI. I can't find any specifications as to it's electronic components, just the manual which is intended solely for the organist. Since it's now working, it does have contacts, but I've had no luck finding out what voltage they were intended for. Seeing as it is originally an electronic organ, I am assuming that the contacts would be intended for a lower voltage. The contacts on the pedal will likely need to be replaced. I don't intend to use the rocker-tabs to use with hauptwerk, but there are pistons which I would like to connect. I'm looking into finding more details, so if you have any more questions, I hopefully can have them in a few days.

Alex.

Do you plan to keep the original electronics of the organ? That would make the job pretty complicated.

In regards to keeping original electronics being more complicated, in my Rodgers 340 conversion, it was actually easier as the original keying circuit voltage was very compatible. I did have to adjust the input resistor voltage divider just a tad, but other than that, I just soldered the ribbon cable wires to the same junction point as the wiring from the key contacts. You just have to know the (original) keying voltage and where to find the key contact wiring connections. Of course if an instrument is switching audio, (fortunately not many of them around) the above idea wouldn't work.

Rgds,
Ed

http://site.virtualorgan.com/community/ ... f=40&t=694

I have learnt a considerable amount about the peculiar properties of Baldwin electronics with emphasis on the method of keyboard switching of the wave forms used to make the audio signals. So if I may comment here a bit.

The Baldwin Organ Company has a has/had a patent on a method of creating the switching signals used, I believe, almost universally in their organs. This consists of a common rail contact bar wrapped in a resistive material. The wires that contact the rail are similar to piano wire and are afixed to the keys. The contact closure is not like a switch but like a switch with some resistance in series with it. The bar is connected to a reference voltage such that when the key is closed this voltage is applied to diodes and eventually to an nand gate IC to allow a 0-5V train of pulses to go through. In the Model 635 that I have, the reference voltage is only 2.5 Vdc. The keyboards are also wired so that the multiplex/demultiplex circuits are grouped in an octave oriented matrix (12 x 6) and not the normal ( 8 x 8 ) matrix. To get the matrix to MIDI encoder to work will require some major rewiring and almost certainly render the internal tone generators inoperative in the process. The most straight forward approach, if you want to go ahead with this method, would be to isolate each key wire from the rest of the organ by cutting a trace on the manual's pc board. Then raise the voltage on the common rail to +5 Vdc and connect each wire to the appropriate place on a 1 x 64 encoder and not use a matrix at all.

There are some hall effect keyboard encoders available which can be retrofitted to many types of organ manuals and can even be added to tracker action keyboards with no degradation of the original action. But they are fairly expensive (around $375 USD per 61 key manual).

If you have access to a tech manual for repairing the H-600, I can possibly assist you more.

Tom