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TECHNICAL PAGES

     Here in what we hope will become a comprehensive source of layman's tech info on the various types of electronic instruments that we use, we will begin a new series. For a start, it seems appropriate that the first instrument that we should consider is the traditional tone wheel Hammond, the first commercially practical electronic organ, and the instrument whose sounds still come to mind when most people think of the words Electronic Organ.
     Widely used, a unique instrument in its own right, worth now much more than when first manufactured, the traditional Hammond tone wheel instrument still enjoys very widespread usage, and indeed we may truthfully say that there is a significant "cult following," if you will, of people who love the music of, and often play these instruments. Here is the table of contents for the Hammond pages, to which, as of 11 03 07 we are still adding information.
     This series is not intended to be a detailed service manual. Rather, it is a look at how these various instruments work, that is, what happens "under the hood," when you press a key to make the music appear.

1. Introduction to the Tone Wheel Hammonds
2. Page one basics of the traditional Hammonds
3. Page two tone generator
4. Page three synchronous motor, starting motor, tone wheel drive details
5. Page four tone wheels, output signal filtering circuits
6. Page five creation of different tone colors
7. Page six tone colors, key switches
8. Page seven matching transformer, define tremolo, vibrato, tremulant, reverberation
9. Page eight graphical representations of tremolo and vibrato
10. Page nine producing vibrato in a Hammond, illustration of phase shifting
11. Page ten vibrato cont. vibrato scanner operation
12. Page eleven introduction to Hammond harmonic drawbars
13. Page twelve. drawbar "take-apart" diagram, introduction to vacuum tube amplification of signals
14. Page thirteen. vacuum tube amplification theory, Hammond console output stage, introduction to some aspects of capacitors in amplifying circuits
15. Page fourteen. Vacuum tube amplification-how Hammond percussion works
16. Page fifteen. Volume envelopes and their effect on perceived tones.
17. Page sixteen. Theory of artificial reverberation using a coil spring.
18. Page seventeen. Hammond necklace reverberation unit.
19. Page eighteen. Electrodynamic and permanent magnet loudpeakers.
20. Page nineteen. Power Amplifiers.
21. Page twenty. Power Amplifiers cont.

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