I notice the increased postings about MIDI control systems, like Bill
Clark and Pat DeWitt's gallant efforts to make their MIDI controlled
instruments.  I think this would be a good time to announce my new set
of plans for building Topsy 3.  I started preparing these plans last
October intending them to be ready by Christmas.  I quickly realised
that these would probably be the last plans I would be issuing, as my
68 MIDI Topsy 3 has proved to be all I will ever want in a portable
organ.  I decided to include a lot more of the information I have
acquired regarding home organ building, in particular the practical
aspects of incorporating MIDI.

What set out to be just the plans to build Topsy have in fact, after
nearly six months work, become a useful handbook for all MIDI organ
builders.  The organ plans describe building everything from a 20-note
hand-turned organ to the full 68-key Topsy 3 which is hand turned or
motor driven.  Finally, there is an appendix giving essential details
to be able to build a 98-note dance organ, using drawings and video
of my own Juliana.  You can see this along with Topsy 3 on YouTube
under "gemmadan".

As well as a practical explanation of how MIDI is used in mechanical
organs, including scales and registers, I have included a section on
electrical and electronic circuits.  This starts with the most basic
requirements including a unique safety device for the battery input,
just one of many original ideas in this publication.

Simple electric wiring shown enables the basic organ to be made.
A register control circuit using just four relays is given.  A novel
mechanical true vibrato device is shown.  There are also a number of
electronic circuits, all of which can be built on strip board using
cheap and readily available discrete components -- no micro or pic
chips involved here!

The circuits include boosting decoder current capacity, vibrato speed
control, auto percussion changeover, automatic drive motor speed
control, tremulant, a 4-way and an 8-way register control, including
how to get extra notes, and finally details for adding an automatic
light display.  As far as I know this is the only such collection of
circuits for use with any MIDI-controlled musical instrument.

Unlike my previous plans which were simply presented as A4 sheets in
a folder, this set are professionally produced and spiral bound, with
a separate book for the drawings.  Everything, including a tour of
Juliana, is supported by an accompanying one-and-a-half hour DVD.

As I have received so much support over the years from American
builders I have once again drawn up these plans in feet and inches and
also include a list of USA sourced materials and suppliers.

I have already issued a few pre-production sets for evaluation and the
main print run should be taking place in the next couple of weeks.
More information can be found at http://www.johnsmithbusker.co.uk/ 

John Smith
Flitwick, UK