M. P. Möller, Opus 3853, 1924

A major element of the museum is the magnificent Möller Concert Organ, which was custom made for the Scottish Rite Auditorium following completion of the Cathedral in 1924. Today, the organ stands in the top three of four of its kind in the United States. Completely restored to its original quality, it is available to qualified organists.

The magnificent pipe organ was designed and built by one of the then largest organ builders in the world - M. P. Möller of Hagerstown, Maryland.

The organ console contains four manuals and pedals, controlling Great, Swell, Choir, Solor and Echo divisions. The main organ is concealed behind the two grills immediately behind the colonnades flanking the proscenium. The chamber on the left contains the Great and Choir divisions, and the right side contains the Solo and Swell divisions. The Echo division is located just to the front of the large rosette in the center of the Auditorium ceiling. A tone chute directs the tones through the spaces in the plaster rosette.

There are over 3,000 individual pipes, ranging from the smallest at about the size of a lead pencil, to the largest at over a foot square and over 32 feet in length. All of these pipes get their wind from three rotary fans totaling about twenty horsepower. The compressed air from these blowers would easily air condition a large building. Electric power to operate all of the many valves in the organ is provided by three 30-amp transformer/rectifiers. The entire weight of the organ is estimated at about 100 tons.

Ballard Pipe Organs, Inc., of San Antonio, has been the organ's curator for over two decades. In 1982, a program of restoration of the instrument was begun. The first phase involved the installation of a multiplexed playing system replacing a bundle of cables about the size of a healthy man's forearm, which ran to various parts of the organ. A multiplex system scans every function of the organ initiated at the console 10 to 15 times per second. Every key, pedal, stop, and accessory is connected to this encoding mechanism. Every scan cycle, the informaiton collected is converted into a digital signal and is sent out via a 12-pair telephone cable to a decoder board in each chamber. The decoding board translates these digital signals back into hand information and switches D.C. voltage to each function seceted by the organist. The first phas also included a complete refurbishing of the Solo chamber and organ components. The chest magnets throughout the organ are old internal magnets which require complete shutdown of the organ and opening of a cover to service. The Solo chamber magnets were replaced with newer magnets which can be serviced from the outside of the chest. Pipework was cleaned and repaired as necessary. The old pneumatic switches and relays were replaced entirely with solid-state drivers controlling all functions, and all wiring was replaced with new PVC-covered cables in accordance with the National Electric Code standards.

The remainder of the chambers are original with the exception of the main pitman chest drivers which are solid-state as are the stop and accessory drivers. Unit stops are, at present, switched by 73-note pneumatic switches. These relays and switches all contain phosphor-bronze contacts which corrode quickly if not used frequently. The resultant oxides do not conduct electricity. Moving contacts in today's instruments are made of sterling silver, the oxides of which will conduct electricity. Eventually, all of these relays and switches will be replaced by solid-state equipment, containing no moving parts.

The console also contained many phosphor-bronze contacts in all of the stop switches, the swell and the crescendo shoe contacts. The keyboard and pedal contacts were replaced with all-new silver contacts in the first phase of the restoration. In late 1993, the console was removed from the auditorium, taken to the curator's shops, and completey rebuilt and refinished. The combination action system, an old pneumatic "hold-set" system, had become unreliable after 69 years, in addition to the problems that the remaining phosphor-bronze contacts were causing. The console was virtually gutted. New stop jambs were built to accomodate all-electric stop-knob units containing hermetically sealed stop switches and electro-repulsion magnets for combination action functions. The board containing the tilting tablet controls for the couplers was also replaced with similar units. The old combination action was replaced with a 32-channel solid-state capture system containing no moving parts. From the outside, the console appears original, but inside it is completely up-to-date by modern standards.