The inner workings of an organ are mysterious to most people. It is a little easier to grasp the concept of a pipe (tangible) organ than an electronic (intangible) organ because of the familiarity with musical wind instruments and ignorance of the laws of physics pertaining to electronics theory and design. Many misconceptions exist about electronic organs. After seeing the inside of an electronic organ, many people have exclaimed something like ” how can all those little parts make musical sounds?!” Some unethical salespersons have spread a popular myth about their analog organs – “it never needs tuning!” – well, only every 5-10 years or so. Assumptions are made by others who compare an electronic organ to any other electronic item, especially a keyboard or computer. I hope you will have a better understanding of the basic electronic organ designs and maintenance requirements after reading this article.
Electronic organs can be divided into several categories, one of which is active components. Tube organs – Analog circuitry using electron vacuum tubes instead of transistors or integrated circuits. Transistor organs – Analog circuitry, mostly, using transistors as active components. Hybrid organs – Analog organs using transistors for small signal control and vacuum tubes for power output. (Hybrid can refer to a cross between anything, not just organs, of course.) Pipe and electronic tone generation combined in the same organ installation is also referred to as a hybrid organ. IC organs – Analog or digital organs using Integrated Circuits as the main active components. An IC is simply a compact package with several hundred or even thousand transistors inside.
Notice the large round ferrite inductor cores (24 per circuit board) used to tune the oscillators to the correct pitch.
Tone generation is another category we may use. Older Hammond organs use a mechanical system to produce tones. They are called tonewheel generators. These organs truly never need tuning. Click on the link for a brief history and thorough description of Hammond tonewheel organs!
Electronic oscillators are another form of tone generation. An oscillator is an electronic circuit that continually switches states to produce a repetitive output voltage level. The values of the passive components in the circuit (inductors, capacitors, and resistors) determine the frequency at which the output signal changes states. Frequency is synonymous with pitch. Tuning (varying the pitch) is usually accomplished by adjusting a potentiometer or a variable inductor to get the exact frequency desired. The waveform of the output determines the basic tone or timbre of the sound. Voicing circuits modify the basic waveform into a variety of sounds. For instance, a sinewave produces a flute sound and a squarewave produces a reed sound. Several different waveforms can be modified and blended, and even distorted, to produce a unique sound. But now we are getting into synthesizers! (I have a 1984 Moog Sanctuary Synthesizer! Same as MemoryMoog – Anyone familiar with them?!)
Digital sampling has produced some fairly authentic pipe organ sounds. The waveform of the acoustical energy emanating from the pipe is sampled (recorded), then digitized (its voltage amplitude and other characteristics are converted to a series of numbers). These numbers are permanently stored in ICs (integrated circuits). When that particular note is called for (by actuating the specific stop and pressing the specific key), the CPU (central processing unit) sends a signal to the ICs to read out those numbers. Then the original waveform is regenerated by a DAC (digital-to-analog converter). As you can see, the computer must be able to respond very quickly, when you consider all the notes that can be played simultaneously from so many stops.
Real-Time Digital Synthesis – A design whereby each note is created in real-time, not stored on a chip. Nested sinewave algorithms compute and generate each note’s vast array of harmonic content each time a key is depressed, creating an overall envelope. Also described as “Active” Tone Generation, whereas Digital Sampling can be described as “Passive” Tone Sampling. Many advantages over sampled organs, such as true note-by-note tonal voicing, allowing precise variation of more than 255 harmonics of one note. Sampled organs are severely limited in this respect.
Mechanical multiplexing vs. Electronic multiplexing – Each key and bass pedal and stop tablet on older organs operated as many as nine switch contacts. These contacts and their miles of wire were necessary to provide the vast array of features of large church organs. Relays provide switching controls of banks of contacts, allowing the switch that controls the relay to have fewer built-in contacts. Microprocessors now offer almost unlimited multiplexing capabilities, but also invite a different set of maladies when these systems fail or get a glitch.
Maintenance – Most technicians never lubricate the stop tablet mechanisms, but they will operate much more smoothly when this is done. All electrical contacts that are exposed to air will eventually oxidize, requiring periodic cleaning to remove the insulating film of oxidation. Motors require periodic lubrication and removal of dust that tends to clog the cooling vents. Belts gradually stretch, requiring periodic adjustment and eventual replacement. Older organs have electron tubes in them. The life of a tube will be lengthened if the layer of dust is removed. Dust acts as an insulator, holding the heat inside the tube. Tube pins and sockets need periodic cleaning, too. Many problems in tube organs are related to oxidized high-voltage pins and sockets, and switch contacts. I recommend an annual preventive maintenance plan which includes removing all tubes, then cleaning the glass surfaces, pins, and sockets, and all the switch contacts. Periodic maintenance has been proven to reduce the number of malfunctions in any electronic organ.
Until recently, most electronic church organs utilized multiple electronic oscillators (tone generators) to create the sounds. Organs of simpler design would use a single oscillator to generate the highest frequency of each chromatic note ( twelve total). Some really cheap organs even used a single high-frequency oscillator to produce a single tone in the mega-Hertz range, which was used by a specialized chip called a Top Octave Generator to produce all twelve top-octave notes. This eliminated the need for eleven more oscillators. The octaves were then created by dividing these twelve pitches in half as many times as necessary to produce the full range of the instrument, usually six or seven. This design was employed in tube, transistor, and IC organs. The more expensive organs utilized an individual oscillator for each note, which provided a richer sound, but greatly increased the cost. This design architecture was employed with tubes, transistors, and integrated circuits. A warmer sound with many overtones is possible with this design, similar to the richness of several human voices on the same pitch, instead of only one. It resembles the overall sound of a pipe organ more than the simpler designs.
An oscillator’s frequency changes over time, due to changes in the component values by age and environmental conditions. It was common for the unscrupulous organ sales person to say these organs would never need tuning. This is simply not true of most designs until very recently. The tuning interval is usually between one and ten years. Many factors affect tuning stability – environmental conditions, oscillator design, component quality, and the accuracy of the last tuning. When an organ is very old (say 40 years or more), the capacitors have usually deteriorated and absorbed moisture until the oscillator cannot be tuned to its correct pitch. Then the capacitor(s) for the incapacitated note must be replaced to bring the oscillator back within its frequency range. When this begins to happen, it is best to replace all of the tuning capacitors at the same time, then perform a complete tuning. The difference is amazing (and the oscillators are good for another twenty to thirty years). This is only recommended if you plan to keep the organ another twenty years, since a new digital retrofit will replace ALL the outmoded electronics in the organ, and offer many new developments like MIDI to your new and exciting tonal variety!
Many times, a prospective customer calls me, describing a problem that sounds like a tuning issue. So when I ask about the last time it was tuned, the customer is surprised to find out the organ goes out of tune. AOB, Saville, Rodgers, Allen, Conn, and Baldwin had large numbers of oscillators in their older models (some as late as 1994). If you aren’t sure about your instrument, contact me with the brand and model number, and I will let you know. Most of these manufacturers are no longer in business, or do not manufacture organs. Only Allen and Rodgers are left, and only Allen builds their organs in the USA and still provides parts for all of their digital models since the seventies.
When Wallace Memorial Baptist Church in Knoxville built their new 7 million dollar addition, I was contracted to remove the Saville 3-manual drawknob organ and 18 speakers from the old sanctuary (now the Chapel) and perform the installation, voicing, and tuning in the new sanctuary. Click here for a few photos of the job.
Most electronic organ systems use several speakers in a variety of designs and configurations – all attempting to create a more realistic pipe sound. These complex systems also need regular maintenance. Grille cloth panels are another overlooked item.
Now you understand why older instruments require maintenance, but surely the newer “digital” organs have no such requirements, right? Wrong! Read on…
All organs have moving parts because of the fundamental means of playing it – putting parts into motion. Keys, drawknobs, stop tablets, expression and crescendo shoes, pedalboard claviers, switches, thumb pistons, and toe studs all require rubber and felt parts for various purposes – absorbing mechanical noise, limiting travel, and guiding the moving parts in a controlled direction. These parts eventually wear out, causing a multitude of problems from minor annoyances to making the organ unplayable. All organ consoles employ an array of mechanical contact and display devices. Over the years, dust and oxidation from contact with air creates an insulating film on the contact surface (which is usually gold or silver), causing a small electrical arc when the contact is closed or opened, which eats into the contact’s thin outer coating of precious metal, creating a high-resistance condition in the circuit that should have essentially no resistance. Over the past several years, some organ companies have begun using tactile pad contacts to reduce cost, but I have personally replaced complete sets of these on three mnaual organs after just three years! All church organs have pedal claviers, which use some form of spring to keep the pedal clavier under pressure, and raised to its resting position. Individual pedal pressure can be precisely adjusted so all pedals are consistent. Spring tension changes with age and use. Some pedal springs lose enough tension to bounce when played in a staccato style, and in severe cases of neglect will actually hang down, causing the pedal to play continuously!
The organist wonders where the extra notes are coming from, while the pedal bounces two or three times as they have gone on with their music. Hardware sometimes loosens, causing pedals to rattle, or even fall off! Many circuit boards have edge connectors to plug them into sockets. I see a lot of problems associated with corroded edge contacts. Power Supplies create the precise voltages necessary for the different electronic subsystems. Some cannot vary more than one-fourth of one volt without causing damage to sensitive electronic parts. Like oscillators, they drift, eventually creating confusing or intermittent problems. Also, power transistors and ICs, which generate heat during operation, will last longer when not coated with an insulating layer of dust. Most organs employ a computer-type memory system to hold registrations. Most of these systems require a backup battery pack to sustain the memory circuits in case of a power failure. I get surprised reactions all the time when I ask “when was the last time the batteries were replaced?” Most rechargeable battery packs last about ten years, some only three. You may think your battery is working fine, but it could be defective without showing immediate signs. If all registrations are lost after a short power outage, the battery pack is probably bad. I have seen some organs refuse to power up because the battery had shorted out. Lithium batteries are nonrechargeable, and usually last two to three years in electronic organs. These organs usually have a Low Battery indicator of some sort, but sometimes it’s just the Power lamp blinking, which may be overlooked or confusing, if you haven’t thoroughly read your Owner’s Manual. To prevent losing your settings, I strongly recommend backing them up on a floppy disc or CD, or writing them down for older organs. When I replace the batteries in an organ, this info is stored in my database for that customer, to prevent loss of registrations and worse, damaged memory circuit boards from battery acid leakage.
The rubber upstops (bumper pad and key guide) dry out and become brittle after about fifteen years, causing a knocking noise when a key is released. In severe cases, the upstop falls off in pieces, leaving nothing but metal to stop the key! See the photo at the top of this page for an idea of what’s involved in replacing them.
But it’s definitely worth it. The key action feels like new, and operation is much quieter.
Organs are more reliable now, due to technological advances in many areas. Allen Organ Company has recently begun using optical key switching on their new Rennaissance Series to further enhance the organ’s capabilities. Their mechanical key switches were the standard of older organs, with individual gap adjustments. Their current design, which employs reed switches and magnets, is considered the most reliable on today’s market. And key contact actuation is still individually adjustable. Custom keyboards are available from some manufacturers which use Hall-Effect transistor switches and magnets. Hall-effects are even more reliable than reed switches because no mechanical contact is necessary, only a semiconductor material which switches states when it passes through a magnetic field. Most older church organ keyboards employ a gold-plated buss rod and gold-plated contact wires for actuation. Unfortunately, contact corrosion and broken contact wires are a common maledy, causing intermittent or dead keys, and ciphers, especially as the organ ages. But new contact wires will last another 20 years or more under normal playing conditions, so it’s best to replace them all if an organ is very old.
Illumined Indicators – Many organ builders now employ LEDs (Light Emitting Diodes) for displays and indicators. These semiconductor devices have no filament to burn out, and come in a variety of colors. But most of the older organs were built with miniature incandescent lamps in their rocker tabs, thumb pistons, drawknobs, and even expression level indicators. To make matters worse, some lamps are not replaceable, such as those used in the thumb pistons on some brands, so the entire piston must be replaced. I recently replaced almost fifty lamps in the drawknobs and rocker tabs in a lighted drawknob organ console, because a few lamps were going out every month or two. That was an expensive all-day job, but a huge savings over replacing them as they burned out! Now they can enjoy another fifteen years of trouble-free drawknobs.
Here is a Card Reader from an older Allen organ. It has six tiny lamps that are used in conjunction with six light sensors to read the data from a punched computer card into the organ to produce one voice. Some card readers have more than six lamps. These lamps eventually burn out, usually one at a time. I always replace all the lamps simultaneously to prevent more service calls in the future. Make sure your organ technician does the same!
The organ industry has many opportunities to increase reliability and reduce malfunctions and maintenance. For decades, a few console manufacturers have been using magnetically-actuated reed switches in pedal claviers and drawknobs. These are hermetically-sealed glass tubes with two metal contacts inside. The contacts close when a small magnet is moved into its vicinity. Since the contacts are in a vacuum, oxidation is negligible, thereby greatly increasing the life of the switch. Hall-Effect transistors have no moving parts, and also operate on magnetic fields, making them even more reliable than reed switches. LED’s (Light Emitting Diodes) have an almost unlimited life expectancy, and have replaced incandescent lamps in most applications. We are seeing more digital control systems in pipe organ consoles, which send digital pipe control signals for thousands of pipes along a single coaxial or data cable, eliminating the large wire bundles we’re accustomed to seeing.
The electronic church organ market is in a volatile state. Some manufacturers have closed their doors, and others are on their way out, in my opinion. In order to survive, some companies have begun using their manufacturing facilites to produce circuit boards for other companies, or moved their production facilities overseas, or quadrupled their parts pricing structure, or applied their American name to an overseas manufacturer’s product. Unfortunately, most of these companies are also attempting to cut manufacturing expenses, which directly affects the quality, reliability, and useful life of the instrument.
While very few electronic organ manufacturers are striving to increase reliability and maintain their level of quality, most are trying to increase profits by utilizing cheaper components. Rubber tactile contacts are a perfect example, since they are now being used in a large number of electronic church organ keyboards and drawknobs. In one well-known brand, I have seen them deteriorate into non-working condition in only 2 years, so the church opted to replace the contact strips on all three manuals at once, since they were eighty miles away. One major electronic organ manufacturer uses cheap plastic thumb pistons that actually melt into deformity from the heat of the internal lamp, and plastic drawknobs that crack and come apart during normal use, and plastic keys that crack! I’ve also repaired their organ amplifiers that use home stereo type components and internal speakers.
A church organ should be built to commercial or industrial grade standards! It is NOT a home entertainment organ. Reliability is very important when someone’s wedding or funeral or graduation depends on this instrument’s ability to perform. If your congregation is considering the purchase of a new church organ, PLEASE ask detailed questions during the sales person’s presentation. Remember… “You get what you pay for” (or less than you pay for, sometimes – but rarely more!)
Even with all of these technological advancements, Preventive Maintenance is still necessary for reliable operation! I hope this information has answered many of your haunting questions concerning analog and digital electronic organs, and pipe organ consoles. I hope, too, that new questions have arisen. Feel free to email us!