Considering drawknob project, looking for some tips

I'm considering a DIY drawknob project for my organ. I'm planning on using Syndyne SDK units. I'm picking up most of the electrical know-how as I go. So far I've determined that I should be able to get something function rigged up with a MIDI encoder and a MIDI decoder. Right now I'm looking at MIDI Boutique products, though I may end up going with Classic's solutions.

A few links:

Drawknobs: http://www.syndyne.com/products/catalog ... olslow.pdf
MIDI encoders: http://largonet.net/midiboutique/produc ... diencoders
MIDI encoders: http://largonet.net/midiboutique/produc ... idencoders

Some questions:

• Which type of encoder would best suit this project? Not sure if I need to use a scanrow or a scanmatrix.
• Which type of decoder would best suit this project? It looks like there are positive and negative common available. The Syndyne units can go either way. Flip a coin to pick between positive vs. negative?
• Take the mdec32 for example. The page lists 2 different firmwares for controlling solenoids. Any idea whether I would need to use mdec32-s or mdec32-pwm? The Syndyne folks told me that I only want to send power to the solenoid while the drawknob is in motion (as opposed to a continuous current). Not really sure if that falls into the "general load" or the "solenoid-driven percussive instruments" category.
• Right now I'm under the impression that I can get this working with the drawknobs, the right encoder and decoder boards, and a soldering iron. Am I leaving out any critical components?

Any insight would be appreciated!

A scanrow or scanmatrix really doesn't matter. You need to add diodes for the scanmatrix, but that's it. It has less wires, but the scanrow is more convenient to wire up. I think it is up to you.

Flip a coin for the decoder polarity.

I don't think you need an mdec32 decoder, they only output TTL levels (5V), which would not be enough for syndine SDK. I think you'll have to buy the mdec32br or mdec64br boards. You'll definitely need the sam firmware.

A critical component: the power supply. Calculate how much current you would need to move all the stops at the same time (general cancel) and allow for some overhead. At 12V your 28ohm coils take about 430mA, about 5watts. 32 of these requires a lot of power.

Hi Rob & Forum,

I am also in the planning stage of building a drawknob console. With anticipation of the release of the Salisbury Willis organ I have decided to build a suitable console for this organ. My initial specs are;

77 Syndyne SDK drawknobs for stops and intra-manual couplers
25 OSI tilting tablets for couplers (Organ Supply Industries make up tilting tablets mounted in a frame, ready for installing on your nameboard or stop jamb)
Syndyne thumb and toe pistons
4 X mdec64-sam by Midi Boutique (for driving drawknobs and tablets. the -sam has a user selectable pulse time for energising the coils. You also need 2 driver outputs for each stop, one for ON and one for OFF therefore, 64 outputs will control 32 stops)
1 HWCE bundle #4 by Midi Boutique (for encoding the state of stops and pistons)
12 VDC, 60 amp power supply for driving the solenoids

Midi Boutique have excelent information on their website including user manuals and wiring diagrams.

I have already flipped the coin and am going with negative common.

All the best with your project Rob.

I just bought the 64 output common negative board from Midigadgets and it is a fantastic board. Each output has a small surface mount LED for it on the board so you can very easily diagnose any wiring issues as you have a clear indication of when the board is trying to energise the coil. Screw terminals also make connection very simple!

What are the costs for both projects? Perhaps if its something reasonable, I might get involved!

Hi Rob and Forum

I've just joined Hauptwerk, so this is my 1st posting. I have listened to various performances you have posted on you tube and so I recognized the name. Here is my opposite situation. 6 Years ago I converted the console of my 18 year old Allen 2+1 into a digitally superior but antique looking Dutch or German Baroque organ. I ended up using at the time all SYNDYNE boards because they were easy to interface and the company gave great support. In addition, they had MIDI boards that would drive the 2 Ahlborn -Galanti sound module, ie. The Classic and the 201. I decided to also use SYNDYNE drawknobs which work in conjunction with the Ahlborn stops. It took me the better part of 6 months working full time to re-make the complete organ case and by the 1st year's end I had about 95% of the organ complete. Due to cost issues it took another year to completely add the remaining 20 drawknobs (out of 40). Now The CLASSIC Ahlborn module went out in a Plasma cloud and rather than persuing a potentially expensive fix I am considering adding 20 Hauptwerk stops along with a Mac G5. I wouldn't mind sharing some experience with you if you still are exploring adding the drawknobs to your system.

regards,