HammondWiki - Diff: TypesOfToneGenerators

Differences between version 7 and previous revision of TypesOfToneGenerators.

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Newer page: version 7 Last edited on May 25, 2016 9:26 pm. by
Older page: version 5 Last edited on February 13, 2009 10:58 am. by
@@ -40,11 +40,13 @@
  7 tonewheels of 192 teeth 
  5 blank tonewheels 
 </pre> 
  
-After the patent was issued and before production began, Hammond figured out a different combination of GearRatio''''s that would change the number of teeth at the Cs rather than at the Fs. To simplify production he kept one standard set of DrivingGear''''s and DrivenGear''''s for each octave. 
+After the patent was issued and before production began, Hammond figured out a different combination of GearRatio''''s that would change the number of teeth at the Cs rather than at the Fs. To simplify production he kept one standard set of [Driving Gears| DrivingGear] and [Driven Gears| DrivenGear] for each octave. 
  
 He also figured out a way to generate a top half octave without 256 tooth tonewheels. The ratio of a perfect fourth to unison is 4:3 or 1.333 times higher. Since 256/192 is approximately equal to 1.333, Hammond cut the top tonewheels to 192 teeth and changed the gear ratio between the driving gears and the driven gears to that a perfect fourth above the desired pitch. In other words, the gear ratio for the upper C was the same as that used on the F tonewheels below it. Because 256/192 is not exactly 1.333, the upper seven pitches are slightly sharper than the other other octaves (another reason a tonewheel generator sounds different than most clones with perfectly divided digital octaves). Only seven tones could be produced using these gear ratios so most generators produce 91 tones. But, because of the way the tone generator was designed, the number of tonewheels in a generator had to be divisible by 12. So five blank tonewheels with no teeth (and no magnetic pickups) were used to keep everything running smoothly. 
+  
+These early organs also lacked foldback in the lower octaves.  
  
 !!! The 82 Frequency Generator 
  
 The folowing models were produced during World War II and have an 82 frequency generator: 
@@ -75,9 +77,10 @@
 In an effort to trim costs during WWII, Hammond reduced, for a time, the number of tonewheels from 91 to 82. The 82 frequency generators eliminated the lowest 9 tonewheels and the organs were rewired to accomodate these missing tones. Hammond used a technique common to pipe organs which produce bass tones lower than the longest available pipe by simultaneously playing two pipes tuned a perfect fifth apart. This produces a _resultant_ frequency an octave lower. By rewiring the organ to play a tonic and its fifth at the same time, a resulting frequency an octave lower was produced. However, this has a negative impact on the quality of the tone. Hammonds do not have perfect fifths and this further limited the quality of the tone. All of the 82 frequency models will be quite old and probably not too common. 
  
 !!! Late Model 91 Frequency Generator (with ComplexToneWheels) 
  
-The following organs were produced from the mid 1940's to the early 1950's and have a 91 frequency generator : 
+  
+After WWII, Hammond returned to the 91 frequency generators and added ComplexToneWheels to the lowest octave that provided additional odd hamonics to the fundamental. This improved the sound of the bass pedals. The following models were produced from the mid 1940's to the early 1950's and have 91 frequency generators with complex tone wheels on lowest octave : 
  
 <pre> 
  Model BV: #17,075 - #29,737 
  Model CV: #17,075 - #30,287 
@@ -86,9 +89,18 @@
  Model C2: #35,001 - #40,459 
  Model RT2 # 1,300 - # 2,150 
 </pre> 
  
-After WWII , Hammond returned to the 91 frequency generators and added ComplexToneWheels to the lowest octave that provided additional odd hamonics to the fundamental . This improved the sound of the bass pedals . The following models have 91 frequency generators with complex tone wheels on lowest octave : 
+!!! Narrow 91 Frequency Generator  
+  
+A short time before the introduction of the 3 series , Hammond redesigned the tone generator to be narrower . These generators can NOT be used to replace the 91 frequency generator above because of differences in the output terminals . The following models have 91 frequency generators in a narrower frame (note that all B3's have the narrow generator) :  
+  
+<pre>  
+ Model B2: #40,304 - through B3 to end of production  
+ Model C2: #40,460 - through C3 to end of production  
+ Model M3: #??,??? - through end of production  
+ Model RT2 # 2,151 - to end of production  
+</pre>  
  
 !!! M Series 86 Frequency Generator 
  
 M series SpinetOrgans were produced from the late 1940's to the early 1960's. To keep production costs down, these organs have an 86 frequency generator: 
@@ -105,20 +117,10 @@
  7 tonewheels of 192 teeth 
  5 blank tonewheels 
 </pre> 
  
-The M series SpinetOrgans use an 86 frequency generator. Since the lower manual ends at F instead of C, generators 13(C) through 17 (E) are not needed. Tonewheels 13 through 17 are "blanks" (i.e. perfectly round) and the pickup magnets are missing. Early M organs use the "wide" generator (but unlike the other organs with the "wide" generator, the output terminals are not in consecutive order) and later M, M2 and M3 organs used the narrow generator.  
-  
-!!! Narrow 91 Frequency Generator  
-  
-A short time before the introduction of the 3 series, Hammond redesigned the tone generator to be narrower. These generators can NOT be used to replace the 91 frequency generator above because of differences in the output terminals. The following models have 91 frequency generators in a narrower frame (note that all B3's have the narrow generator):  
+The M series SpinetOrgans use an 86 frequency generator. Since the lower manual ends at F instead of C, generators 13(C) through 17 (E) are not needed. Tonewheels 13 through 17 are "blanks" (i.e. perfectly round) and the pickup magnets are missing. Early M organs use the "wide" generator (but unlike the other organs with the "wide" generator, the output terminals are not in consecutive order) but it's not known for sure how many. Later M, M-2 and M-3 organs used the narrow generator. 
  
-<pre>  
- Model B2: #40,304 - through B3 to end of production  
- Model C2: #40,460 - through C3 to end of production  
- Model M3: #??,??? - through end of production  
- Model RT2 # 2,151 - to end of production  
-</pre>  
  
 !!! 96 Frequency Generator 
  
 Used in later console organs such as the H-100 and X-77. 

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