The Organ Forum

Actually there is a way to midify an organ with audio keying and that is to utilize high frequency audio in the ultrasonic region say 40Khz or higher that will not interfere with the audable region.  With newer design detectors and components it should be quite do-able.  Maybe some of you Conn and Hammond owners could pursue this further.

Trying using DC and blocking caps, the transients would be in the several volt range and would probably saturate the audio.  Conversely, if you used a very low voltage DC, the audio would trigger the logic signals.

In all of the workaround ideas, one still can't get the velocity for the MIDI that is so nice with many of the MIDI sound generators.  That still takes two sequential contacts per key.

Superimposing audio signals above the hearing range would involve a mass number of detectors and filters.  Any such signals would have to be filtered before any audio amplifier, as they would still push the instantaneous input to the amp and cause it to flattop unless normal program level was limited.

For a product that is sold, we must also keep switching frequencies below 10KHz or have to get FCC certification in the USA.

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Fred

fredy2:

Trying using DC and blocking caps, the transients would be in the several volt range and would probably saturate the audio.  Conversely, if you used a very low voltage DC, the audio would trigger the logic signals.

Thanks for the information.  I have wondered about it for quite some time and I think you have expressed the objections very well.

David

Fredy2: are you right about 10khz? Normal high notes of analog keyed organs have frequencies and harmonics above that. Don't you mean 10mhz? Microprocessors in lots of equipment (microwaves, blenders, etc. other things today that have processors) is 1 to 4 mhz and I don't see FCC certification on those.

 It seems that injecting a voltage into one set of contacts and then filtering & detecting would be more work than adding in a new contact bar. The bus bar us usually a common output to the audio circuits, so you'd have to give it a DC offset then tie into a set of contacts and detect that DC offset while filtering out the audio when a key contact makes contact with the common bus bar. It doesn't seem like the best option.

For regular organ work, you only need on/off. Velocity and pressure not required for organs unless you are running MIDI pianos or imitating a tracker organ. So I think the Midi9 would be too expensive and with Artisan, you still need key contacts for their $90 contact input board.

So for me it comes back to what type of contacts are best to add? Whatever is added, for an organ, you would still need some method of adjusting the contact point for each key and if you want 2nd touch, you have another thing to add and adjust - if there is room for 2 contact sets. Ignoring the cost of the input board (Artisan or other) it seems you can't really get below about $1 per key contact and up to $2 each (covering optical, microswitch, magnetic or old organ style mechanical contact block with a wiper). I'd appreciate suggestions. I do see a problem with anything optical: bugs, spiders, dirt and dust unless things are cleaned once in a while.
 

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Digital Pipes
http://pstos.org/instruments/wa/seattle/lajko.htm

No, the FCC rules are certification required above 10KHz, NOT MHz.  The reason is that switching waveforms contain harmonics.  For instance, a square wave contains ALL odd harmonics in amplitude divided by their harmonic number.  Some devices are grandfathered before the rule, but many have certified subsystems within.  The devices don't necessarily have to have a label IF they have been certified and type approved such as blenders, etc.

Most velocity sensing is done with a double silicone dome arrangement using two conductive rubber pills that contact two areas of inter-digitated fingers of etch on a circuit board under the keys.  The fingers on the board are coated with a black, very hard material... don't know what it is... so the rubber pills don't wear away the etch.

I am quite sure this method has been engineered to the max for cost effectiveness.  There is NO individual adjustment and doesn't seem to be any reason for it in all I have seen.  The silicone rubber domes carrying the conductive rubber pills take care of the over-travel of the keys.

These contacts appear to be quite durable and don't suffer the plating wear-off that many do.  The contact resistance is on the order of less than 1000 ohms and is compatible with CMOS technology for interface.  Essentially all of these keyboards are scanned as a matrix using disconnect diodes for each octave to avoid backfeeds between notes.

 

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Fred

Fred,

Your post was interesting. I'm also wondering what the material is on those rubber domes. I installed two of these keying systems under my Hammond X-66 keyboards, then routed wiring to the circuit boards placed inside the organ. I completed the job about 3 months ago and so far everything works perfectly. However, midifying the pedals was a little tougher. I use the midi outs to a PC running Hauptwerks. Theater Pipe second touch works great.

George (G3) 

I don't have the specs on the rubber pills and the specs may be trade secret stuff too... however it is a conductive silicone rubber of some sort... probably carbon-loaded to make it conductive.

Done right, the literature says they can last 100 million cycles.

A Roland keyboard that had failure, was easily restored by cleaning both the circuit board and the pills with 91% isoprophyl alcohol.

 

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Fred

Just for fun why not differentially compare the buss bar with each signal contact using an op amp or comparitor whose output is hi pass filtered, then detected.  Detector output equals key up,  no detector output equals key down.  This could be implemented with smt and multi op amp packages.  Quite a few analog components,  kinda big if you use 741 or related ic's.  Any ideas?

 

The noise pickup and even the capacitive cross talk created by attaching to such low level signals would couple and corrupt the normal audio.  Even using FET input comparators would still load things... No free lunch here...

 

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Fred

jbird604:

But if you want to explore some less expensive options, there are some European MIDI suppliers that have very bare-bones MIDI-out adapters. One that I have personally done business with is Roman Sowa of Poland. I've used a couple of his very cheap adapters, and they did the job. Just no frills. Here's his website:

http://www.midi-hardware.com/products.html

John

 

I was going to ask about him. How good and fast are Roman Sowa's components compared to Syndyne or other expensive boards ?.

I have a Baldwin Church organ from the 60's (vacuum tube, 2 manuals & 32note pedal board, not sure which model) beyond repair and was thinking about converting it to midi compatible, though i haven't decided whether to go for a Hauptwerk system or all hardware sound module.

Does anyone know any inexpensive hardware sound module manufacturer ?. Ahlborn modules are toooo expensive.

Hello..

 

Why not take a look at www.gino-midi.nl?

Nico Goes has developed a MIDI keyboard controller that I am using since a long time..

The good part is: It needs only a small Atmel processor...And it controls two 5-octave manuals and 32 note pedal, or three 5-Octave manuals, without pedal, and also controls up to 64 stop-switches, or pistons by CC Program Change messages...The designs are available on that website. The only disadvantage is that you will have to make the PCB yourself...(single-sided), and wire your keyboards in an 8x8 matrix..

The programmed processor only costs 17,50 euro.I am playing with the latest MyOrgan on the Gino system,  an organ with 2 manuals, 1 30-note pedal and 50 stops...It works flawless...He ships it worldwide from Holland...and all the neccesary steps to make the PCB's are on his website...Including lay-outs, schematics, photo's and he is very helpfull. It is a non-commercial project...

I guess totally with my old Domus console and reed switches for the pedal, the whole project has cost me less then 100 euro....I have installed this interface project at several satisfied customers now...

With kind regards,

Etude57 (Rieks van Dijk)

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www.virtual-organs.com.
MyOrgan, new sample-sets, and Praelude.

It seems one of my questions doesn't have an answer: what contacts to add to an existing organ. While there are lots of choices for a midi controller, not much is said about contacts. Membrane contacts that connect when the key is fully pressed and bottoms out is not good for organs as contacts usually make when the key passes the half way down point. I have a Conn 651 that needs extra contacts. Mainly I need to add orchestra bells, but when I do that the contacts should be usable for anything (not the old 32 note contact strip that went with the bells.) So I guess I'll go and design the contact assembly and let you know when it is ready. I have to be done before Christmas because the bells are mandatory for Christmas songs (and the midi module I have that has marimba and other percussions.)

I'll make midi out from it or/and design it to work with other midi controllers on the market. I'll make it read the contacts of a pipe organ, too, because you just can't install a diode matrix on existing 1 wire per key contacts of pipe organs.

 

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Digital Pipes
http://pstos.org/instruments/wa/seattle/lajko.htm

Yes, hi there :

 

I use the products from www.midi-hardware.com. He is from Poland and his name is Roman. I use modules BBS64 for 1 wire per key input, very straight forward.

For a 2 manual organ that should be about  200 Euro ( $ 300 dollars ) for all MIDI hardwar

Quote: Why not take a look at www.gino-midi.nl

WITHDRAWN

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Bob Collins
Zion Organ
http://zionorgan.com

come on..what nonsense is this? Nico Goes, the owner of Gino-Midi is a honest Dutch guy..His hardware designs are fine, inexpensive, and his site is not infected with anything else then the hobby-enthousiasm that he has for his own developed system..

[ FLAME] I suspect this is a kind of hoax from the HW clan to kill the competition....Maybe you have to check your virusscanner....[FLAME OFF]

This is just nonse...Nico has customers world-wide.. check the facts..of find a better way to give the competition a bad name...

With kind regards,

Rieks van Dijk, (Etude57)

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www.virtual-organs.com.
MyOrgan, new sample-sets, and Praelude.