Appendix to TOPSY August 2006

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My original Topsy has now been performing for over a year. It has always attracted a lot of attention mainly because of the musicality of what is coming out of such a small box. I have had to do nothing to the organ except adjust the celeste for the Bourdons after a couple of months use, and this has stayed OK since. A number of other Topsies are being built and for those aiming for the full 64 keys I have recommended enlarging the case slightly to accommodate larger bellows and give a bit more space on the windchest. The first to be completed is just 2 inches wider and plays full 64 (65) key arrangements with a cranking speed of 60 rpm, the crank throw was increased to 1 ½ inches. A windscreen wiper motor was used and this can be switched to run slowly for testing (tuning pipes etc) and full speed for normal playing. The organ has now been used at a number of events and worked well.
I have devised a simple register control for Topsy using 3 relays or just 2 and a transistor. This is only suitable for the basic pipe arrangement and uses the celeste output as a reset for the Glockenspiel it may be necessary to increase the lengths of the Glockenspiel pulses in the midi control. The John Wale boards now have sockets fitted for the output chips and can be set for any midi outputs needed, by the user.

These 2 are the same redrawn by me for better clarity.

This is the original diagram sent in by
John Smith.

Click on the diagram you want to enlarge.

Relay version redrawn for better clarity.

Transistor version redrawn for better clarity.

Thanks to John Smith for sending this article in to the A.O.B.G.