From simon@alphabeck.co.uk Tue Dec 04 15:35:51 2012
Subject:Re: Transpose a B3?

Not only is it true, the fact that a tonewheel organ's pitch is linked directly to the mains frequency (60Hz in America, 50Hz in most of Europe) is part of its design. Its inventor, Laurens Hammond invented a synchronous motor (one whose speed is determined by the power supply's frequency rather than its voltage), initially to use in clocks. During the Great Depression, clock sales started to dwindle, and Hammond tried to find other uses for his motor. Fixing a steel cam to the spindle and holding it near an electromagnet connected to an audio amplifier, he found he could produce a sound he described as an "electric flute", which led within a few years to the design and launch of the Hammond tonewheel organ in 1935.

Simon