Hammond Tone Wheels

This table shows how the exact frequencies that a Hammond organ produces are generated. Starting from a driving shaft spinning at exactly 1200 RPM, a pair of gears drives each tone wheel at a suitable rate for the teeth on the wheel to generate the desired wave. The resultant frequencies are neither exactly equal-temperament (only the "A" note is exactly standard pitch) nor exact harmonics of each other, but are close to both. The deviations may contribute to the timbre of chords played on the instrument, however.

Wheel #GearingGear RatioRotationTeethToneOutput
Frequency
Wheel #
DrivingDrivenRevs/SecHz
(1200 RPM)
1851040.817316.34622 C32.6921
271820.865917.31712 C#34.6342
367730.917818.35622 D36.7123
41051080.972219.44442 D#38.8894
51031001.030020.60002 E41.2005
684771.090921.81822 F43.6366
774641.156323.12502 F#46.2507
898801.225024.50002 G49.0008
996741.297325.94592 G#51.8929
1088641.375027.50002 A55.00010
1167461.456529.13042 A#58.26111
12108701.542930.85712 B61.71412
13851040.817316.34624 C65.38513
1471820.865917.31714 C#69.26814
1567730.917818.35624 D73.42515
161051080.972219.44444 D#77.77816
171031001.030020.60004 E82.40017
1884771.090921.81824 F87.27318
1974641.156323.12504 F#92.50019
2098801.225024.50004 G98.00020
2196741.297325.94594 G#103.78421
2288641.375027.50004 A110.00022
2367461.456529.13044 A#116.52223
24108701.542930.85714 B123.42924
25851040.817316.34628 C130.76925
2671820.865917.31718 C#138.53726
2767730.917818.35628 D146.84927
281051080.972219.44448 D#155.55628
291031001.030020.60008 E164.80029
3084771.090921.81828 F174.54530
3174641.156323.12508 F#185.00031
3298801.225024.50008 G196.00032
3396741.297325.94598 G#207.56833
3488641.375027.50008 A220.00034
3567461.456529.13048 A#233.04335
36108701.542930.85718 B246.85736
37851040.817316.346216 C261.53837
3871820.865917.317116 C#277.07338
3967730.917818.356216 D293.69939
401051080.972219.444416 D#311.11140
411031001.030020.600016 E329.60041
4284771.090921.818216 F349.09142
4374641.156323.125016 F#370.00043
4498801.225024.500016 G392.00044
4596741.297325.945916 G#415.13545
4688641.375027.500016 A440.00046
4767461.456529.130416 A#466.08747
48108701.542930.857116 B493.71448
49851040.817316.346232 C523.07749
5071820.865917.317132 C#554.14650
5167730.917818.356232 D587.39751
521051080.972219.444432 D#622.22252
531031001.030020.600032 E659.20053
5484771.090921.818232 F698.18254
5574641.156323.125032 F#740.00055
5698801.225024.500032 G784.00056
5796741.297325.945932 G#830.27057
5888641.375027.500032 A880.00058
5967461.456529.130432 A#932.17459
60108701.542930.857132 B987.42960
61851040.817316.346264 C1046.15461
6271820.865917.317164 C#1108.29362
6367730.917818.356264 D1174.79563
641051080.972219.444464 D#1244.44464
651031001.030020.600064 E1318.40065
6684771.090921.818264 F1396.36466
6774641.156323.125064 F#1480.00067
6898801.225024.500064 G1568.00068
6996741.297325.945964 G#1660.54169
7088641.375027.500064 A1760.00070
7167461.456529.130464 A#1864.34871
72108701.542930.857164 B1974.85772
73851040.817316.3462128 C2092.30873
7471820.865917.3171128 C#2216.58574
7567730.917818.3562128 D2349.58975
761051080.972219.4444128 D#2488.88976
771031001.030020.6000128 E2636.80077
7884771.090921.8182128 F2792.72778
7974641.156323.1250128 F#2960.00079
8098801.225024.5000128 G3136.00080
8196741.297325.9459128 G#3321.08181
8288641.375027.5000128 A3520.00082
8367461.456529.1304128 A#3728.69683
84108701.542930.8571128 B3949.71484
8584771.090921.8182192~C4189.09185
8674641.156323.1250192~C#4440.00086
8798801.225024.5000192~D4704.00087
8896741.297325.9459192~D#4981.62288
8988641.375027.5000192~E5280.00089
9067461.456529.1304192~F5593.04390
91108701.542930.8571192~F#5924.57191
92blank---92
93blank---93
94blank---94
95blank---95
96blank---96
Wheel #GearingGear RatioRotationTeethToneOutputWheel #

The wheels indicated in light blue are not exact octaves of their lower equivalents.