Audio Input Connections; Line-Level Input Connections - JBL GTQ 190 Owner's Manual

GTQ 190 - English 06/03/98 11:49
• Simultaneous Stereo + Mono Connection–
Each of the two groups of the GTQ amplifier
may be used to drive a stereo pair of
speakers with a mono speaker at the same
time. This is sometimes used for center-
speaker applications or for inexpensive
subwoofer addition with two-output
amplifiers. Unlike a true bi-amplified
subwoofer connection, however, this type of
system configuration does not provide fine
control of subwoofer-satellite balance. It
requires the use of a passive subwoofer
crossover instead of the superior active
circuitry already built into GTQ amplifiers,
and it does not separate the power amps
driving the satellites from the amps driving
the subwoofer. With the 4 speaker outputs
already available on the GTQ amplifier, a
stereo + mono connection for subwoofers
should not be necessary. If you wish to add
a center speaker, connect the main pair of
stereo speakers as in the stereo mode;
connect the mono speaker as indicated on
page 9 for bridge-mode connection. A high-
power L-Pad or power fader can be used to
attenuate the center channel for proper level
matching. Each speaker should have an
impedance that is equal to or greater than 4
ohms. The input-mode switch for the
channel pair being used in Simultaneous
Stereo + Mono should be set to STEREO.

Audio Input Connections

Line-Level Input Connections

• Proper wiring between the signal
source, any other components in the
system, and the GTQ amplifier will help
keep noise levels in the system low. Use
high-quality, twisted-pair cable or low-
capacitance shielded wire.
Side 9
Keep the wire as short as possible. Do
not splice together shielded wires. Do
not run audio signal wires alongside
power wires for an extended length
either for the amp or the vehicle's
standard power wires. When wires are
run for long distances, separate the
audio signal wires from power supply
wires or vehicle wiring harnesses as
much as possible. When signal wires and
power wires must cross, try to keep them
perpendicular. Avoid routing any wires
near accessories such as ignition control
modules, tachometers, fuel pumps or fan
motors.
• The line-level inputs of GTQ amplifiers
accept standard phono plugs (also called
RCA plugs). The outputs of most head
units, equalizers, or crossovers also accept
phono plugs. If another type of connector
is used, adapters or special cables may be
needed. Proper wire and connectors can
be obtained from any JBL authorized
installation specialist.
• Note: GTQ amplifiers have 2 built-in
frequency-selectable low-pass crossovers
and also 2 frequency-selectable high-
pass crossovers. Be sure the crossover
switches for each group and the preamp
outputs are properly set for the chosen
system configuration (see "Typical
Applications" and "Add-On and Upgrade
Steps" sections for suggestions). If you
have any questions about how to set the
crossover switches, contact your local
JBL dealer.
(–) (+) (+) (–)
L
C C
SPEAKER LEVEL INPUTS SPEAKER OUTPUTS
LINE LEVEL PREAMP
BRIDGE
R GR2 L
INPUT OUTPUTS POWER
+ – – + + R – + L – FUSE
GR1 GR2 GR1 GR2
30A
GR2
L
GR1
+ – – +
R GR1 L BATT(+) REMOTE GND
R
+ R – + L –
BRIDGE
) ( – ) ( +
SPEAKER LEVEL INPUTS
LINE LEVEL PREAMP
SPEAKER OUTPUTS
R GR2 L
INPUT OUTPUTS BRIDGE
+ – – + FUSE
GR1 GR2 GR1 GR2 POWER
+ R – + L –
30A
GR2
L
+ – – +
GR1
R GR1 L
R BATT(+) REMOTE GND
+ R – + L –
BRIDGE
) ( + ) ( – ) ( + ) ( –
Simultaneous Stereo-Mono Connection Diagrams
09