Last updated: 7 March 2014. Click About This Website for update list.
For over fourteen years the most stable and extensive reference source on the Internet for pipe and electronic organs
The hub of this site is the Complete Articles page which gives you instant access to many detailed articles dealing with numerous technical aspects of both pipe and electronic organs. Use the Google search box below to quickly identify areas of interest. While browsing, why not also listen to over three hours of music played on the three manual organ below and the Prog Organ virtual pipe organ here?
This article completes the trilogy which covers electric actions from their roots in the 1890s to the present (see below for the other two). It describes a hard wired approach to circuit design which is more economical in terms of component count than alternatives such as conventional diode keying. Like the latter, it employs switching at two points in each magnet circuit - at the keys and at the coupler gates - but its implementation at a detailed level is significantly different. Instead of using very large numbers of electronic coupler switches each realised using discrete transistors, diodes and resistors, this approach uses miniature telecoms relays for coupling. Keying is then done electronically using a single transistor in each key circuit, regardless of how large the organ might be and how many couplers and unit chests it might employ. Thus the number of transistors in any system always equals the number of keys on the instrument using this method - just one transistor per key. For this reason the approach is called TinyTran to denote a transmission using a smaller number of transistor switches than conventional systems.
By using plug-in relays of the type suggested, maintenance in the field should be greatly simplified. At the same time the compelling advantages of maintainability, graceful failure and resistance to obsolescence exhibited by diode keying are retained. However, because the system uses far fewer components than conventional diode keying, particularly regarding the number of transistor switches required, it should be cheaper because of lower component and assembly costs. It should also exhibit enhanced reliability and survivability for the same reasons.
Shows how fully electronic organ actions can be assembled from basic components including diodes and transistors using the technique known colloquially as 'diode keying'. A coupler switch is described in terms of a diode AND gate, and it is also explained how an electromagnet can be driven using a transistor. Using only these two types of generic circuit module, it is demonstrated that a wide range of actions can be constructed to suit any organ with any mix of intra- and inter-divisional couplers. Given a systematic approach, identifying and replacing faulty components in a diode keying system is no more difficult than it was in the days of electromechanical actions. This is not necessarily the case with other types of electronic transmission. For such reasons diode keying sits well with the conservative technology and dignified longevity expected of a pipe organ, and it is for this reason that the article was written in the hope that it might assist those who wish to understand more about how it works.
Describes how the electromechanical keying systems used in pipe organs since the time of Robert Hope-Jones in the 1890s were wired. There are still many such instruments around otherwise it would not be possible to obtain the action components today, therefore it is anticipated the article will address the needs of those who wish to maintain, repair or simply understand them - many such people have asked me for information over the years, so here it is! It is also the intention that the article might have some historical value. Circuits applicable to intra- and inter-divisional couplers are described, as well as those appropriate to organs using slider and unit chests. The extension principle is explained at the circuit level, together with some particular issues related to the fully unified organ such as the need for key relays. It is pointed out that well-designed electromechanical actions usually fail gracefully rather than catastrophically, they are readily maintainable, and they are more robust than their electronic counterparts against eventualities such as lightning damage.
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The picture above is of a test rig used for experiments on pipe organ valves, such as those described in the articles entitled Calculating Pallet Size, Touch Relief in Mechanical Actions and Response Speed of Electric Actions. These can also be accessed from the Complete Articles page where summaries are also available.
This electronic organ is a dual purpose instrument containing both "straight" and "theatre" voices, designed and made by the author. It is tuned to the author's Dorset Temperament with the addition of some impure octaves as described in Keyboard Temperaments with Impure Octaves. A full specification is available for download here (PDF file, 117 kB).
The things they say:
These recordings span some years and they were made in various rooms and auditoria. The older tracks were made using analogue equipment and some were recorded acoustically using microphones, hence the occasional noises due to piston thuds and page turns, etc. Other tracks were captured electrically. All are of real players performing in real time - no synthetic MIDI 'performances' here. I have not got round yet to normalising the volume settings of all the tracks so they are compatible with each other, therefore you might wish to adjust the volume between tracks depending on which ones you select. Do not be alarmed if some tracks appear to start with an excessive noise level - this simply means they were recorded at a higher level than others. Just turn the volume down to suit. In any case, it is a wise precaution to always begin playing each track at a low level to protect your audio equipment and your ears from unexpectedly high signal levels when the music begins. Although the instrument has 13 ranks of theatre organ voices in addition to its 'straight' sounds (see specification), copyright considerations preclude the inclusion of much theatre-style music here. Playing time 1 hour 35 mins approx.
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