Posted by: John   in

This page is specifically for the virtual pipe organ I am building.  Since I am just now getting started on this page, I will do this in sections.  

I finally decided to do it!  I have wanted to build a virtual Hauptwerk organ for years, but finally have the chance!  Some friends from church gave me a Baldwin organ that did not work.  But it was a decent console cabinet and had the keyboards in it and has a full pedalboard.  No bench though.

Console Cabinet

The console was originally very heavy.  Lots of stuff in it, including a ton of wiring.  Here are some pictures of things that were in it, and what it looked like after removing all of that stuff.

Stuff from inside the cabinet

More stuff from inside the cabinet

Pedal switch stacks, expression pedals, and power supply

Old stop tab assembly

All of this stuff, with the exception of the expression pedals came out and pretty much thrown away.  I kept the keyboard switch stacks around because I am using the little wire fingers in them for the new keyboard switching.  It is much simpler than the old assemblies.  Once all of the extra stuff is out of the cabinet, this is what it looks like.  Ignore the mess in the garage.

Empty cabinet

Now for the rebuilding.


The existing keyboards used the old keyboard switch stacks for return spring action.  The keys and levers are mounting on a springy vertical metal piece, but there was no resistance once the old switch stacks were removed.  Additionally, they were mounted on some massive metal brackets that were going to be very difficult to modify for height and position.  However, each keyboard has it’s own smaller metal bracket that I was able to mount on a new wood chassis.  I used some alder that Home Depot had cheap.  Here’s the bottom keyboard mounted in the cabinet.

Bottom keyboard mounted in cabinet

To address the lack of return springs, I punched 61 holes in the back chassis board and tapped in paneling nails.  I purchased a couple hundred small springs on ebay and used them for the return springs. 

Putting in the nails

Nails and key ends

Attaching the springs

The springs provide just about the right amount of tension.  The keyboards feel natural enough (very similar to the Allen I play at the church).

The next issue was switching.  The first attempt was to use some of the existing old boards from the original organ with the wire fingers.  I used some angle aluminum and made a bracket to hold them.  Getting this put together was a royal pain because of the spacers I used inside to keep everything electrically disconnected.  I used the aluminum key ends as the electrical common, polished them up with a wire wheel and soldered 61 wires in a harness.  Yes, that is Cat5 cabling…I had a mile of it sitting around.  The idea was when the key end lifted and contacted the wire, the connection was made and the MIDI board sent the signal to the computer.

Switch stack with MIDI scanner board

Switching detail

Switching detail

This worked pretty well, at least initially.  The problem was, the aluminum did was all aluminum does and started to oxidize.  That made the connections electrically unreliable.  There is a second attempt in process that does not use the aluminum as part of the connection process.  This is proving to be much better.  I will post more on this when I build the second stack.

Here is the cabinet with two keyboards mounted in it.  There will eventually be a third keyboard.  I am seriously considering making keyboards.  I have the design figured out.  Time and money…

Two keyboards

Expression Pedals

These will vary depending on the organ.  The original console (and most modern electronic organs) have a pedal for the Great/Pedal divisions (bottom keyboard and pedals) and one for the Swell division (second or third keyboard).  Real pipe organs are different.  Pipes produce sound at only one volume level.  The Great and Pedal divisions are unenclosed, meaning the pipes are out in the open and there is no volume control other than stop selection.  The Swell division is enclosed, meaning the pipes are in a box with shutters.  Volume, or expression, is controlled by using the pedal to open or close the shutters.

Some organs have what is called a Crescendo pedal.  Pressing it will gradually add stops (or turn them off). 

For the organ I will be using most, the upper keyboard uses an expression pedal.  This console has two pedals, so the left one will not do anything.  Naturally, they had to be modified some in order to work properly with the computer.  Here is a look at the original circuitry at the back of the expression pedals.

Original wiring and potentiometers

Not much to it really.  However, the potentiometers (pots) did not relate well to the MIDI hardware.  I installed the little adjustment boards I got with the MIDI stuff and that made them work pretty well.  The boards were designed to be soldered straight to the pot tabs.

Pot adjustment boards

These feed back through the pedal MIDI scanner.


These have proven to be a pain.  The conventional pedal contact system uses magnets and reed switches.  To that end, I purchased some small magnets and some reed switches.  I found this to be a royal pain to set up and they are very touchy.  However…they are working for the most part.  I do not have good pictures of these, but I am going to do something different with these, just not sure what yet.

Pedal ends before modification

Magnet and circuit boards

The idea was to put a magnet at the end of each pedal. When the pedal was depressed, it would trip the reed switch right in front of it.  However, I found the trip points inconsistent.  Also, magnet activity seems to transfer to the adjacent reeds at times.  I am not sure what I can to do fix that situation, I may try a different type of switching scheme.  Not sure what yet.

Stop Tabs

As could be seen from the original console pictures, the stop tabs had a ton of circuitry.  The original tabs were also manual press only.  If a registration was saved as a preset, then used later, the tabs would not change to reflect the selected stops.  Selecting a preset as a starting point, then adjusting with the individual tabs would be difficult to impossible. 

I looked at purchasing stop tabs, but at $10-$12 each I said no thanks.  These would have been rocker tabs, like the Allen at church has. Nice to be sure, but expensive.  I determined to make  my own.  I decided on simple momentary switches.  The MIDI hardware sees switches of this kind as an electronic toggle.  Press once, it sends the “on” signal, press again, it sends the “off” signal.  The MIDI hardware allows a LED to be turned on and off based on the on/off signal from the switch.  Additionally, if the computer sends a signal to change a stop, either by using the virtual console or by a preset, it will toggle the LED. 

The organ I am using has 50 original stops.  The virtual organ adds 5 that were digitally added (the person who made the virtual set felt there were a few deficiencies and added them), for a total of 55 stops.  I built the stop rail with 58 stops.  If I were to ever use an organ with more, I will have to either use the virtual console on the computer, or go without. 

First, I made the bezel out of some oak lumber. I knew I would have to take it apart to work on the switches and wiring (and also to make final cuts for fit once the third keyboard is done) so it is put together with screws.  It is stained in “Colonial Maple”, but it looks like a warm oak.  It does not quite match the mid-brown of the cabinet, but does not look bad either.  I then took a piece of poplar that I machined down from 1/4″ thick to about 3/32″ thick.  I then measured and punched 58 holes 1/2″ diameter.  The momentary switches were mounted into it.  I built a mounting bracket and installed it and the switch rail into the bezel.  I had to make sure to leave a gap for wiring.

Bezel with switches, back view

Bezel with switches, front view

For the stop tab fronts, I made a bunch of oak wood tabs, machined down to about .15″ thickness, 2″ tall and .7″ wide. 

Fresh cut stop tabs

Lots of sanding on these.  I did not want to stain them the same color as the bezel, so I used a “Red Oak” color on them.  I used some JB Weld epoxy to attach the tabs to the switches.  This picture shows this process, as well as the stain colors.

Stop tabs being assembled

Note the 5 mm hole in the tabs for the LED to go through.

Here’s the assembly with the wiring, also showing the original (and now replaced) green LEDs. 

Wiring and green LEDs

Stop tab MIDI hardware

Stop rail with green LEDs and keyboards

As you can see from the last picture, the stop rail turned out pretty good.  The problem I have run into is that the green LEDs viewing angle was too narrow.  The ones right in front of you show up real good, but the ones on the edges are difficult to see when they are on.  They have been since replaced with some opaque yellow ones, shown later on.

Cost for these came in about about $1.50 each.

Toe Studs

These are proving to be a royal pain.  On modern organs, toe studs are generally used as presets.  However, on the organ I am building, they will be used to control other aspects of the organ, namely coupling and ventil controls.  The actions of the orignal organs, being mechanical, meant that they were depressed by foot and locked in place until manually released.

Like the original stop tabs, I wanted them to be momentary, push once for on, again for off, and settable with presets.  However, they need to be a lot more sturdy than the stop tabs.  Looking for toe studs for purchase was an exercise in expense…about $33 each, and I needed a minimum of 14.  Again, too expensive.

I determined that I could make toe studs a lot cheaper.  I got some 1.5″ hardwood balls, some 1/2″ oak dowel and some springs.  The prototype for the studs looks like this.

Toe stud prototype

A magnet at the end of the dowel would come in proximity of a reed switch to make the contact.  The problem I have run into is that the dowel tends to bind in the holes and does not travel freely.  Sometimes it works well, sometimes it does not.  I have attempted to finely sand the shafts as well as the holes, and that has helped, but the consistency problem still exists.  So, I am still contemplating what to do to with it.

Here is what one side of the toe studs looks like in the cabinet, along with the retaining pin inside.

Toe studs in the cabinet

Retaining pins, before circuitry

 They are generally useable, and cost about $2 each to make.

Cabinetry and Labeling

Obviously, the pictures in the keyboard section show chassis and bracketing that should be hidden.  For that, I manufactured key cheeks, but decided to level them with the keyboards instead of leaving the cabinet open between the keyboards and sides.  This was basically a matter of making the pieces and putting them together.

Keycheeks being manufactured

One side assembled

Left side installed

Right side installed

Note on the right side there are two pushbutton switches in the bottom keycheek.  I needed a means to get the MIDI control boards into the programming mode.  This was the easiest way to allow that.

Along with the keycheeks, I needed to make the front covers for the keyboards.  These are where the preset buttons generally go.  I made these with 5 buttons on each for general presets, and 4 buttons for divisional presets.  The single button on the right is the General Cancel button.  Here’s the keycheeks and covers in place, along with the temporary location of the stop rail.

Keycheeks and covers in place

Preset buttons on the cover

I made some labels for the stops, cut them out, and taped them to the bezel with some white electrical tape.  It looked pretty tacky, but worked for a while.  Part of the beauty of the Hauptwerk organ is that it is not limited to just one organ.  There are lots of them that can be used on the same console.  With the exception of the toe studs, the rest of the console is designed to be generic.  However, I do not want to tape pieces of paper to the stop rail bezel if I decide to change organs.  I decided to use pieces of 1/8″ thick plastic and make a bracket to set them in.  For the labels, I got some letter size clear labeling that I could run through the printer. 

First, I had to make the bracket to hold the labels.  I got a piece of 90 degree oak molding and machined it down to fit the top piece of the stop rail bezel.  I had to cut 1/4″ off the insde edge of the bezel.  Once the bracket was spaced properly, I just screwed it in place.  Here’s what it looks like reassembled.

Stop rail bracket

I cut the plastic to the proper sizes for individual divisions, one piece for Pedal, one piece for Recit (Swell), etc.  After cleaning up the edges, I printed out the labels and attached them to the pieces.  Here’s the one for the Pedal.  Since these are for a French organ, they use the French spelling. 

Pedal stop rail labels

You will note that some stops are in black, others in red.  The black stops are foundation stops (Strings, Diapasons, Flutes) and the red are the reed stops.  (The reeds can be enabled, but not used until one of the foot levers is activated.)

Here’s a picture of all four stop rail labels in place.

Stop rail labels

Earlier, I mentioned that the green LEDs were not working out as planned.  They worked, but were difficult to see unless right in front of the organist.  Also, when the windows blinds were open, you couldn’t see if they were on at all.  The answer was to change them to opaque yellow LEDs.  While I had the stop rail out for the label modification, I changed the LEDs.  Here’s what they look like with some of them on.

Stop lights

I mentioned earlier that there was no bench with the organ.  I had some pine boards in the garage that I decided not to use for the keyboard chassis.  So, I spent a few minutes and just knocked together a bench.  It actually turned out pretty well.  I have since added a couple other boards to give it some more strength, but overall it has been all right.


Computer and Software

I am currently using a computer with an i3 CPU and 16 GB of RAM.  I need more RAM, but this mainboard only supports 16 GB.  At some point, I need to get a new mainboard that will hold more.  Hauptwerk loads the organ into RAM for immediate action, so the more RAM, the better it performs.

Speaking of software, I am using Hauptwerk 4.0, made by Milan Digital Audio.  I have the Advanced version, meaning it has no restrictions regarding memory or its polyphony ability.

Hauptwerk comes with a 30 rank English organ, a very full-featured unit that sounds pretty good.  However, English organs are not my favorite style.  I much prefer the French Romantic organs that were made from about 1860 to 1910.  There are several sample sets out there.   Milan Digital Audio’s flagship organ is the 1903 Cavaille-Coll organ at Notre-Dame de Metz, France.  It is a very well made sound set. 

What I decided on though, was the 1885 Cavaille-Coll organ at St. Etienne in Caen, France, made by Sonus Paradisi.  I was able to download a demo set and found it sounded much more “alive” than the Metz organ.  It is also a larger instrument, having 50 original stops instead of 38.  The full Caen set adds 5 stops to bring it’s total to 55, while the Metz organ has an option to add 10 stops for a total of 48.  There were several reasons to go with the Caen organ aside from number of stops and the sound.  It was cheaper ($725) but it was also built by Aristide Cavaille-Coll while he was still alive.  The Metz organ was built after his death in 1899 (even though Charles Mutin, Aristide’s successor built a number of organs in the same style).  The building at Caen is also larger, having about an 8 second reverb that is part of the sound set.  Metz is about 6 seconds.  The Caen sample set also can be played in full surround…if I had the sound card and speakers to take advantage of it.  Both organs have been maintained as finished and are truly original and authentic instruments. 

The connection between the console and the computer is a simple two-port MIDI adapter that plugs in by USB.  All the console does is provide switching.  The sound is done by the computer.  All that needs to be done to load another organ is to purchase and install it.  The console switching will need to be set in the computer so it knows that buttons go to which stops, and new plastic labels will need to be made, but that’s really about it.  Once the programming is done and saved, switching between organs only takes a few minutes. 

So, there it is for the moment.  There is a lot more to do, but the organ is useable and it sounds incredible!