Expander Modules, Part I

May. 14, 2016

For its day the Ahlborn-Galanti sound modules [photo] were "state of the art" -- not up there with today's Hauptwerk / Grand Orgue sample sets but a great piece of kit in its day.

They're good enough to integrate seamlessly with real pipes, they really "warm up" the tone of earlier digital organs as well, and even today there are many organists who would be glad to have this module serving as a backup playable system in case the computer driving their Hauptwerk console happens to be inoperable.

The fact is, this module is much easier to install, configure, manage and much better from a practical viewpoint even though from a tone quality viewpoint Hauptwerk would be better.

While created mainly to be a support module to augment the voices of Ahlborn-Galanti organs, other digital organs, and MIDI-equipped pipe organs, these units were practically a stand alone complete organ of 2 manuals and pedals in a box.

They feature organ stops of exceptionally high quality organized in an ideal sound archive controlled by lighted reversible buttons which can be configured to operate from the organ's piston memory or even the drawknobs of a new console.

The stops are recalled via MIDI and integrated with the existing organ in order to achieve increasingly new and interesting registrations for high authenticity and enriched sound effects.

A special programming section in these units permits the organist to voice every single stop and to gain access to a large number of general controls including an incorporated 5-track sequencer [26,000 events] which offers numerous advantages both for practicing purposes and in worship services.

These were available both as a table-top model and drawer-type.

The module's 3 divisions [Division A, Division B, Pedal] are summed into 2 channels creating a stereo signal, thus both of its output jacks [R/L] need to be run in series to the speaker system.

It's possible with certain self-contained consoles so equipped to feed both outputs of the module back into the organ's stereo "line in" inputs, negating the need to use a separate external speaker system, but it's much more preferable to connect both outputs of the module in series with the inputs of an external reverb engine, 31-band equalizer, and powered subwoofer, in that order, with all inputs/outputs being balanced [3-pin XLR] where feasible, and then on to the passive stereo speaker system at hand.

Four different versions [Classic, Romantic, Archive 201, Archive 202] were built, all identical in operation with the difference between models having to do with the stops lists which offer a different tonal palette in each case.

Each stop list adds 20 stops [10 stops in Division A -- 6 stops in Division B -- 4 stops in the Pedal] and over 20 additional ranks, all controllable by means of a built-in combination action with setter button, general cancel, 5 memories, and 6 general pistons for a total of 30 combinations.

Divisions A and B can be assigned to any MIDI channel in the organ with all stops independent, no borrowing or unification, playable separately or all on one division if desired.

Manual 16-foot stops go all the way to the bottom without breaking back, and all stops are playable individually or in combination with 4 divided windchest layouts for all organ voicing functions and controls with total pipe organ compatibility.

The volume of each stop and its characteristics such as scaling, articulation (chiff), release, pipe wind, pitch adjustment, fluctuation, harmonic presence, rank character, tuning, historic temperaments, crescendo, and tutti can be programmed to taste and controlled from the module's liquid crystal display (LCD) panel.

Some may wonder why Ahlborn engineers envisioned a circuit topology in these units for 6 channels and provided only 2 outputs-- the circuit board however, as a possible scenario, may have come right out of a production model Ahlborn-Galanti organ having 2 channels per division made into 2 channels overall by using resistors as a mixer, possibly to keep the module from competing with said production model organ.

More channels is always better than fewer for producing quality sound, but critics shouldn't be too hard on the engineers for mixing 6 channels down into 2 channels like this and may want to train their attack on complete organs -- the Sampled Wave Processing technology incorporated into these modules obtained from real organ pipes is simply outstanding, quite realistic, and its features provide the organist with an expansive tonal palette for coloration of sounds and an expanded dynamic palette for nuancing the music, something to be treasured in any organ. 

MIDI jacks for IN, OUT, THRU, two adjustable tremulants, Auto Pipe Tracking capable of automatically tuning the module to a real pipe organ, master volume control, and headphone jack also were standard features.

NOTE:  The internal memory battery supplied with each model is a solder-in, nickel-cadmium type and is on the main circuit board -- this battery has been reported by a few owners after many years of use to be prone to leak right into nearby circuitry, and so, to keep the module working some of them, as a preventive, have contemplated switching out the original battery with a replacement battery mounted off the main board.

The replacement battery which fits this can be purchased from local battery stores or ordered online and may be either nickel-cadmium type, nickel-metal-hydride type, or lithium type, making sure its voltage is correct (3.6 volt).

Owners should be cautioned that some tricky disassembly for this is required -- there are 10 little screws which must first be removed from the back and bottom of the box, then the top lip of the back of the module needs to be gently pried off from the top.

Care must be exercised when these 2 pieces are pulled apart in order not to mess up the cable going from the main board to the front panel, as this connector is delicate and easily damaged.

The battery pack will be found on the main board, but to work on it the main board needs to be taken off the chassis, and it may be impossible to do this without removing one of the four rubber feet of the module.

Common sense regarding static discharge also needs to be exercised, and getting the battery out can be tough without special equipment as it may not move in the least when applying some force to it.

Even with special tools the risk of damage to the main board seems quite high because the contacts are very close to the board.

From the outside, the original battery may not show any visible signs of wear or leak whatsoever, and the whole package can seem intact, like new, which usually indicates no replacement is needed.

As for changing the battery pack, the unit must be turned off, and, to make things easier in the future, it would help to take advantage of the opportunity to solder-in some extension wires and then wire it to a cordless phone battery pack -- some velcro can be put on the battery pack and somewhere convenient in the unit so the new battery does not bounce around when moved.

Because settings are lost when changing the battery it's best to write them down before getting started with this.

Because installing a fresh battery causes a complete reset with changes applied and restored in memory it also might clear up any other issues with the unit.

Sometimes, for example, and possibly battery-related, if there would ever be a data corruption leading to erratic behavior to where a manual reset would be needed, the instruction manual that comes with the module says nothing about restoring the factory state.

To do this one would press the SET piston on the module and simultaneously press pistons 1 thru 5.

It's a bit tricky to do this, but it will work, and the LCD panel will say MEMORY PUFF.

Of course, this will erase any programming and voicing settings, but it's better to have all functions restored and working again even if the player has to start from scratch.

Again, before doing any functionality reset, it would be advisable to write down any settings.

If a problem develops with the LCD panel itself to where, for example, it seems to be degraded to the point where it only displays random pixels, the solution would be to replace it.

(con't in Part II)

• Overview