RichardWFaith
In 1965, give or take a year or so, I acquired a Hammond C3 organ for use in Casey Kasem's "Band Without a Name". By that time in my life (age 19), I had already become an avid electronics tinkerer, and so came to perform a number of modifications and experiments on the organ. Some produced useful effects, and some ultimately wreaked ruin upon the instrument; however, I learned much from this work. In particular, I came to appreciate what an advanced work of art that instrument was, considering the vintage of its design, and I came to understand certain features of its electronics front-end design that were apparently all-but-forgotten until operational amplifiers became common. The theory behind its drawbars must have been counterintuitive to most who studied the organ's schematics: the summation of tones occurred in multi-tapped CURRENT TRANSFORMERS whose secondaries were connected to LOW-INPUT-IMPEDANCE preamplifiers, and it appears to me that perhaps the only reason why this design never seemed to bewilder large numbers of electronic service people is that these parts of the organ hardly ever failed, and thus hardly ever needed troubleshooting of any kind.
Another aspect of the B3 design that has greatly impressed me from the beginning is the tonewheel generator system and its inherently precise intonation. Even very recently, I did some Internet research and obtained a complete frequency table for the 91 tonewheels. From the latter table, I compiled an Excel spreadsheet with some additional columns of my own making: I show the Hammond frequencies in comparison with the equivalent true-equal-temperament frequencies, and include computation of the difference between the former and the latter in "cents". Also, one of the added columns shows that throughout the entire range of generators #1 through #84, there is absolutely no "shading"; that is, all octaves are EXACT; however, generators #85 through #91 are all somewhat sharp; my table tells precisely HOW sharp each of them is, in "cents".
If anyone would like a copy of my spreadsheet (provided of course that I don't get more requests than I can handle), I will be happy to attempt to share my spreadsheet. The only hurdle that I anticipate in this regard is in the discreet use of e-mail without making myself or anyone else susceptible to the receipt of unwanted mail or invasion of privacy; to these ends, I request the advice of the webmaster/moderators.
In addition, I invite Q & A from interested readers, and hope that something I have to offer is helpful.
Richard William Faith
Another aspect of the B3 design that has greatly impressed me from the beginning is the tonewheel generator system and its inherently precise intonation. Even very recently, I did some Internet research and obtained a complete frequency table for the 91 tonewheels. From the latter table, I compiled an Excel spreadsheet with some additional columns of my own making: I show the Hammond frequencies in comparison with the equivalent true-equal-temperament frequencies, and include computation of the difference between the former and the latter in "cents". Also, one of the added columns shows that throughout the entire range of generators #1 through #84, there is absolutely no "shading"; that is, all octaves are EXACT; however, generators #85 through #91 are all somewhat sharp; my table tells precisely HOW sharp each of them is, in "cents".
If anyone would like a copy of my spreadsheet (provided of course that I don't get more requests than I can handle), I will be happy to attempt to share my spreadsheet. The only hurdle that I anticipate in this regard is in the discreet use of e-mail without making myself or anyone else susceptible to the receipt of unwanted mail or invasion of privacy; to these ends, I request the advice of the webmaster/moderators.
In addition, I invite Q & A from interested readers, and hope that something I have to offer is helpful.
Richard William Faith