Hammond L series - How the Organ Operates; 1-1. General Operation Principles; 1-2. Tone Source Mechanism

SECTION
I
HOW
THE
ORGAN
OPERATES
1-1.
GENERAL
-
This
section
contains
a
description
of the
operating
principles
of
L—100
Series
organs.
Figures
1—1
and
1
-2
depict
the
locations
of
the
various
subassemblies.
Figure 1
-3
is a
block
diagram.
1-2.
TONE
SOURCE
-
Most
tone
sources,
such
as
strings,
reeds,
or
pipes,
produce
complex
tones.
The
Hammond
tone-producing
mechanism,
however,
generates
individual
frequencies
which
can
be
combined
by
means
of
harmonic
drawbars
to
produce
any
desired
tone
quality.
The
block
diagram,
Figure
1-3,
shows the chief
components
of
the
instrument.
Electrical
impulses
of various
frequencies
are
produced
in the
"tone
generator
assembly"
whicli
contains
a
number
of
"tone
wheels"
driven at
predetermined
speeds
by
a
motor
and
gear
arrangement.
Each
tone
wheel
is a
steel
disc
similar
to a
gear,
with
high
and
low
spots,
or
teeth, on
its
edge
(see
Figure 1
-4).
As
the
wheel
rotates,
these
teeth pass
near
a
permanent
magnet,
and
the
resulting
variations
in
the
magnetic
field
induce a
voltage
in
a
coil
PEDAL
DRAWBAR
CONTROL
TABS
LOWER
MANUAL
DRAWBARS
PILOT
LIGHT
OFF-ON
SWITCH
UPPER OR
SOLO MANUAL
LOWER
OR
GREAT
MANUAL
PEDAL'KEYBOARD
EXPRESSION
(VOLUME) PEdAL
Figure
1-1.
L- 100
Console,
Front View