Hammond SKX, Reference Manual

Page: 120 / 398

Drawbar Effects - Leslie
106
Ë
LESLIE®
Your Hammond SKX has a built-in digital Leslie effect that replicates the sound of a twin-rotor Leslie Speaker cabinet.
In addition, the SKX can also be used with a variety of different Leslie Speaker cabinets. There is a full explanation of
how to use the SKX with a Leslie Speaker cabinet starting on page 20.
What Is A “Leslie Speaker?”
When the Hammond Organ was first introduced in the mid 30's, it was not “self-contained” - in other words, the sound-
producing apparatus was not contained within the console. In order to hear the sounds produced by the organ’s tone
generators, a separate “tone cabinet” containing an amplifier and speaker system had to be connected to the organ console
via a special cable. The Hammond Organ Company for many years manufactured many different models of tone cabinets
specifically for use with Hammond Organs. The best known of these is probably the PR-40 model, which used a 40-watt
tube amplifier to drive a set of speakers.
Hammond PR-40 Tone Cabinet
A typical Leslie Speaker cabinet.
The Hammond engineers had very definite ideas about what a Hammond Organ should sound like and the Hammond
speakers were designed to deliver that sound. In the late 30's, however, an independent engineer and organ enthusiast
named Donald J. Leslie wanted a sound from a Hammond Organ more nearly approximating the sound of a theatre organ,
particularly a realistic theatre organ tremulant. He found that rotating a baffle in front of a stationary speaker created
the effect of a tremulant (the well-known “Doppler effect”) and called the subsequent speaker the “Vibratone.” (The
“Vibratone” designation was eventually dropped and subsequent models would be known simply as Leslie Speakers.)
Over a hundred models of Leslie Speakers have been made over the years; probably the best known being the models
122, 142, 145 and 147, all of which have 40-watt vacuum-tube amplifiers. The122 and 147 are both 41" tall (see above
photo), while the 142 and 145 are 33" tall. The 122 and 142 have the same electronics, as do the 145 and 147.
Although the 122 and 147, as well as the 142 and 145, share identical cabinet designs, they are electrically dissimilar -
the 122/142 is designed specifically for use with a Hammond Organ whose preamplifier has “GG” terminals (a
“balanced” signal output), whereas the 147/145 has an “unbalanced” input more suitable for use with self-contained
organs - other brands as well as Hammond. Additionally, the 122 and 147 have different high-frequency responses - the
122 rolls off the treble at 6K to reduce key click, while the 147 does so at 8K, resulting in a slightly brighter overall
sound.
HA<O> SKX
Owner’s Playing Guide