A Message from the President !

Over eighty members attended the Manchester meeting in October – as many as I can remember for quite some time. The central interest was, of course, Kenneth Tickell & Company’s new cathedral organ. Building such a large dual action, two-console organ in a confined space was a technical challenge and the Tickell team are to be congratulated for pulling it off so successfully. The stunning casework is a fitting tribute to Ken’s artistry.

Next to be visited was the fine Hill rebuild by David Wells in the Church of the Holy Name, its magnificent sound being perfectly enhanced by the acoustics. Such organs are now very much back in vogue and are increasingly the must-have style for new organs. The tour of the Town Hall organ on the other hand showed it to be in a rather sad state. We look forward to its rejuvenation as part of the £350 million refurbishment of the complex. The side visit to Salford University’s acoustics lab and Alan Taylor’s talk were also well attended and stimulated a good discussion. Thanks to all who played a part in the success of the weekend.

I hope the following might elicit some responses. At present, 16VDC is the low voltage standard used in organs in the UK. It lies uncomfortably between the 12V and 24V standards widely used in industrial and automotive applications and used by organ builders on the continent. John Norman tells me its origin lay in belt driven DC generators that were originally designed for trolley buses. Having experienced the inconvenience of mixing 12V continental stop key units with 16V British soundboard magnets and wanting to use standard 12V contactors and relays from Farnell and RS Components in the more complicated organ systems, perhaps now is the time to bring ourselves into line with the outside world.

If so, the choice of the higher of the two voltage standards is a no-brainer. In simple theory, one is swapping less copper for more insulation. However, the insulation requirements at such low voltages are minimal. In practice the insulation used for 12 and 16V is no different to that for 24V. The higher voltage is comfortably within the rating of modern semiconductors.

If there are no significant disadvantages, what are the advantages? Voltage drop rather than current capacity often dictates the size of cable we use. If we retain the same cable sizes, then the voltage drop is reduced dramatically. Using easy numbers, a current of 3 amps at 16V becomes 2 amps at 24V for the same power of magnet. Let’s say the cable resistance is 1 ohm and the volt drop reduces from 3 volts to 2 volts. Expressed as a percentage of the supply volts, the corresponding drops are 3V/16V = 19% and 2V/24V = 8%. That is a reduction to 44% of the previous figure.

A 30-amp power supply could either provide 50% more power or could be replaced by one of 20 amps, possibly avoiding the need for forced ventilation and the attendant noise. Fuse ratings can be lower, giving better protection to cables. These factors – voltage drop, power supply size and fuse protection – will become even more critical as magnet design evolves and there is a move from electro-pneumatic to direct electric actions which draw much higher currents. It would be good if there were a consensus across firms on this. As always, your views are welcome.

I close by wishing all our members and readers a Merry Christmas and prosperous New Year!

Andrew Moyes - President