The Organ Forum

I have not found anyone talking about add-on contact assemblies for electronic organs. It seems there is only talk of midi interfaces that connect to existing pipe organ contacts. So I am finishing the design of an add-on contact assembly for electronic organs. My first organ add-on will be for a Conn 651 that I have in the auditorium of a senior center in Seattle. I need (i.e. MUST) add on a set of orchestra bells for Christmas music. I have 4 different sets of bells so getting the orchestra bells is not the problem. Adding an extra set of key contacts is the main problem.

Does anyone have a cross sectional view of a Conn 65x 3 manual theater organ? It is hard to tell the space available between the manuals and the contact assemblies. I need to insure the PC board will fit and the contacts are in the right place.

 If there exists a cross section diagram with dimensions that would really help. I've examined the organ and it is hard to tell the space available in and between the keyboards & existing contact assemblies. I do have an original brass contact assembly for a Conn, but that doesn't help much as I have no photo of where it was mounted in a Conn organ. If I had that, I could make a PC board no bigger than the original mechanical contact assembly and maybe have an off-board midi control board not on the contact board in order to keep the contact board as small as possible. Right now the initial design has the midi interface on the same board as the contact assemble.

I have a programmable Midi driver finished to drive the orchestra bells (Thomas, Conn and other brands) and now I need to finish the PC board for the keyboard contact assembly. The contact assembly will have midi out drive the bells or other midi devices.  So I will soon have add-on contact assemblies that could be added to Conn organs and probably any other organ. So a cross sectional view of a Conn 65x would help to insure what I do will fit. I can do trial and error, but time is limited. Please help if you can.

FYI:  I have seen tons of posts for midi interfaces that connect to existing contacts (wire per contact or diode matrix) but never anything regarding adding another set of physical contacts. You can't connect to contacts of analog organs, like the Conn, because they switch audio and not voltage as in a real pipe organ or newer DC contact keying systems. (OK, there was one, but it was designed more for pianos and electronic keyboards. It made contact when the key was fully depressed. For an organ, you need to be able to adjust the contact point to match the existing contacts of the organ so they all make contact at the same time. Plus you may need to adjust a set for 2nd touch.)