Expander Modules, Part I

May. 14, 2016

The Ahlborn Archive series of expander modules [photo] manufactured by the Italian firm of Ahlborn-Galanti were created to be augmentation support modules for Ahlborn-Galanti organs, other digital organs, and MIDI-equipped pipe organs.

They feature organ stops of an exceptional high quality, organized in an ideal sound archive.

The stops can be recalled via MIDI and integrated with the organ in order to achieve increasingly new and interesting registrations for high authenticity and enriched sound effects for the playing of organ literature.

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 -- an incorporated 5-track sequencer [26,000 events] offers numerous advantages as well, both for practicing purposes and in worship services.

This device, which was available both as a table-top model and drawer-type, is practically a stand alone complete organ in a box.

The module's 3 divisions [Division A, Division B, Pedal] are summed into 2 channels, thus BOTH output jacks [labeled R/L] of the module need to be used in order for the speaker system to receive a full signal.

It's possible with certain self-contained consoles so equipped to feed both outputs of the module back into the organ's "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 with 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 a separately amplified passive external speaker system equipped with a crossover network to bring out the very best this gear has to offer.

Four different versions [Classic, Romantic, Archive 201, Archive 202] were made, 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 combination action with 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 voices playable on one division or separate divisions, all without any borrowing or unification.

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.

In addition, each stop volume and characteristics such as chiff and even wind noise can be adjusted to taste and controlled from the module's liquid crystal display (LCD) panel.

Some may wonder why Ahlborn engineers designed a circuit topology in these units for 6 channels and only provided 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.

The number of channels does seem to make a difference in the quality of sound, more channels is always better than fewer, but critics shouldn't be too hard on Ahlborn 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 in these modules is simply outstanding, quite realistic, and its features provide the organist with not only an expansive tonal palette for coloration of sounds but also an expanded dynamic palette for nuancing the music, all of which is something to be treasured. 

Other features these modules offer include historic temperaments, programmable temperaments, MIDI IN, OUT, THRU, programmable MIDI channels, programmable crescendo, programmable tutti, two adjustable tremulants, individually activated stop units, Auto Pipe Tracking capable of automatically tuning the module to real pipes, master volume control, and headphone jack.

NOTE:  The internal memory battery supplied with each model is a solder-in, nickel-cadmium type, now banned, and is on the main circuit board -- this battery after many years of use is prone to leak battery acid right into nearby circuitry, and so, to keep the module working its original battery should be switched out with a replacement battery that's mounted off the main board.

The replacement battery which fits this can be ordered from local or online electronics parts houses or, as an alternative, a cordless phone battery may be substituted making sure the voltage is correct (3.6 volt).

Some tricky disassembly for this is required however -- approximately 10 little screws must first be removed, 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 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 battery may not show any visible signs of wear or leak, and the whole package can seem intact, like new, which usually indicates the battery is the original one.

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 down the settings 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, there can be a data corruption which can lead to erratic behavior to where a manual reset would be needed, but the instruction manual that comes with the module, while comprehensive, 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 voicing settings, but it's better to have all programming functions restored and working again even if the player has to start from scratch.

Players might want to write down beforehand any settings they're wanting to keep before doing a functionality reset.

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