The organ described in [Lauren Hammond's|LaurensHammond] patent application was never marketed and existed in prototype form only. The tone generator illustrated in the patent produced 89 frequencies starting at C0:
- 5 tonewheels of 2 teeth
- 12 tonewheels of 4 teeth
- 12 tonewheels of 8 teeth
- 24
tonewheels of 16 teeth
- 12 tonewheels of 32 teeth
- 12 tonewheels of 64 teeth
- 12 tonewheels of 128 teeth
+ 5 tonewheels of 2 teeth C0-E0
+ 12 tonewheels of 4 teeth F0-E1
+ 12 tonewheels of 8 teeth F1-E2
+ 12 tonewheels of 16 teeth F2-E3
+ 12
tonewheels of 16 teeth F3-E4
+ 12 tonewheels of 32 teeth F4-E5
+ 12 tonewheels of 64 teeth F5-E6
+ 12 tonewheels of 128 teeth F6-E7
-In the patent organ the number of teeth on the tonewheels change at F instead of C as in the production organs. Also note that there are twice as many 16 toothed tonewheels as the other octaves. This required two different sets of [Gear Ratios|GearRatio] that changed at
F3 to make this odd arrangement of tonewheels work correctly. There are no tones above the sixth octave like there are in the production organs because the hobbing machine used to cut the sinusoidal "teeth" in the tonewheels could not cut 256 teeth. Hammond didn't solve this problem until just before the Model A was introduced (see Early Model info below).
+In the patent organ the number of teeth on the tonewheels change at F instead of C as in the production organs. Also note that there are twice as many 16 toothed tonewheels as the other octaves. This required two different sets of [Gear Ratios|GearRatio], one set for E3 and below and a different set for
F3 and above
to make this odd arrangement of tonewheels work correctly. There are no tones above the sixth octave like there are in the production organs because the hobbing machine used to cut the sinusoidal "teeth" in the tonewheels could not cut 256 teeth. Hammond didn't solve this problem until just before the Model A was introduced (see Early Model info below).
!!! Early Model 91 Frequency Generator
The following organs were produced from the mid 1930's to the early 1940's and have a 91 frequency generator:
