GTQ 190 (serv.man2) - JBL Car Audio User Guide / Operation Manual. Page 10

10

When speaker-level signal is used to
drive the GTQ amplifier, the signal goes
into the amp through a special eight-wire
harness/connector (see the “Controls and
Connectors” section). If extension wires
are needed between the head unit output
and the amplifier unit, use conventional 
speaker wire or twisted-pair wiring. Keep
the wiring inside the passenger and trunk
compartments, and make the wires as
short as possible. All connections should
be securely crimped or soldered and
insulated with heatshrink tubing.
• Use the color code of the input harness
wires and the identification on the
radio/tape deck output wires to be sure
that left and right channels are correctly
connected and the positive/negative
polarity of each channel is connected
correctly. For example, the left positive
output of the head unit must be
connected to the left positive input of the
GTQ amplifier.
• The Universal Interface Speaker-Level
Input may also be used to accept the
signal from a preamp-level balanced-line
driver capable of at least 4V output. To
utilize this option, terminate the signal
leads from the balanced line driver to a
Molex Mini-Fit Jr series 8P connector.
The color code for the speaker-level input
harness is as follows:

Group 1 Left (

+

):

White

Group 1 Left (–):

White with 
Black Stripe

Group 1 Right (

+

):

Gray

Group 1 Right (–):

Gray with 
Black Stripe

Group 2 Left (

+

):

Green

Group 2 Left (–):

Green with 
Black Stripe

Group 2 Right (

+

):

Purple

Group 2 Right (–):

Purple with 
Black Stripe

In some systems it may be desirable to
use both the speaker-level inputs and
line-level inputs simultaneously. For
instance, if you have a stock head unit in
your car you may connect the speaker-
level inputs of the head unit to the GTQ
amplifier. You may simultaneously
connect a CD player equipped with a
volume control to the preamp-level
inputs of the GTQ amplifier. Note: Front &
rear channels of the radio/tape and the
CD player must be driven into the group
1 and group 2 inputs of the amp (use Y
cables if necessary). The group 2 input
switch must also be set to the group 2
position. The Universal Interface circuitry
of the GTQ amplifier will isolate the inputs
from each other while mixing both

signals. Therefore switching from one
source to the other is as simple as
turning the unused source off, and
turning the desired source on. No other
switches or relay boxes are needed.
When using this setup it is also possible,
using the wiring setup shown below, to
allow either of the two sources to
remotely turn on the amplifier. This is not
necessary if the factory radio is of the
high-power BTL type. The Common
Sense turn-on circuit will activate the
GTQ amplifier when using the powered
source, and the conventional remote
connection of the preamp-level source
will activate the amp when it is used.

These switches are set according to the
number of inputs connected to the amplifier
group and the desired mode of operation.
See the diagrams on pages 4 and 5, and the
descriptions below for options.
• Conventional Stereo Operation – Set the
appropriate group mode switch to ST for
stereo. Connect the preamp-level head unit
outputs either to the two gold line input
connectors or connect the head unit speaker
outputs to the speaker-level inputs. When
using two head units, both the speaker and
preamp-level inputs may be used
simultaneously. Be sure to maintain left and
right channel consistency.
• Bridged Mode Operation – To select bridge
mode operation, set the mode switch for the
appropriate group in either the L only or L

+

R

position. In the L position, signal from the left
input is fed to both left and right amplifier
outputs for that group. In the L

+

R position,

the signal from both the left and right inputs
is summed internally. When using a group of
the GTQ amplifier for mono mode fed with a
stereo signal it is best to use the L

+

R mode.

When feeding a single GTQ amplifier
channel group with a mono signal from an
outboard crossover, use the L mode and
connect your source input to the left input of
the desired group to be used in bridged
mono.
• Simultaneous Stereo 

Mono – Set the

Mode switch for the appropriate group to the
stereo position. Main speakers are connected
normally to the left and right stereo outputs
of the group, and a center speaker or
subwoofer speaker is connected to the same
group as in bridged mode. Refer to the
diagram on page 9 for connection details.

GTQ 190 - English  06/03/98 11:49  Side 10