JBL Stereo Amplifier GTS100 User Manual

GTS100  
2/1 CHANNEL AUTOMOTIVE POWER AMPLIFIER  
OWNER’S MANUAL  
 
Introduction  
By providing this two-unit direct connec-  
tion, Universal Interface circuitry elimi-  
nates the need for an FM modulator to  
connect a CD player to factory radios,  
improving the fidelity of digital playback.  
Thanks for purchasing your new  
GT series automotive amplifier. The  
GT series amplifier you have chosen  
includes many unique features to  
enhance its performance and utility.  
The power amplifier circuitry is a  
fully discrete design notable for low  
distortion and unusually clean and clear  
reproduction quality. Your GT series  
amplifier will easily connect to virtually  
any car audio system, whether it is  
factory installed or purchased  
Also, when using a high-powered (BTL)  
radio through the speaker-level inputs,  
Common Sense turn-on circuitry  
senses the common-mode voltage  
present on the radio’s speaker wires  
and turns the amplifier on without an  
additional “remote” wire. When the  
speaker-level inputs are used exclu-  
sively, the preamp-level inputs may be  
converted to preamp-level outputs to  
drive additional amplifiers or signal  
processors.  
separately.  
In addition to conventional preamp-level  
inputs, this model features JBL’s  
Universal Interface design, which facili-  
tates simple connection to factory  
radios with the low distortion that is usu-  
ally only associated with preamp level  
connection. With Universal Interface, a  
factory radio can be used either as the  
main music source or combined with a  
CD changer which includes volume  
control capability, simultaneously  
In addition, the built-in active crossover  
provides either high-pass or low-pass  
operation. This lets your GT series  
amplifier power either subwoofer or  
main speakers in a bi-amplified system,  
without the expense of an additional  
crossover.  
connected directly to the amplifier.  
3
 
About Installation  
Features  
Although the GTS100 was designed to  
make installation as easy as possible, it  
is a sophisticated product that requires  
proper installation to realize its full per-  
formance potential. Skill with tools, an  
understanding of basic electronics, and  
experience with car stereo installation  
are needed to properly install these  
amplifiers. If you feel you do not have  
the necessary knowledge and skills, we  
strongly recommend that the instal-  
lation be done by your authorized  
JBL dealer. If the GTS100 is installed  
by a qualified JBL dealer, we will double  
the length of your warranty to two years  
from date of purchase.  
Bridgeable 2/1 Channel Operation  
Simultaneous Stereo + Mono  
Operation  
Built-in Staggered 18dB/Octave  
100Hz High-Pass and 80Hz Low-Pass  
Crossover  
No Current Limiting  
Oversized Floating Rail MOSFET  
Switch-Mode Power Supply  
Common Sense 2-way Turn-On  
If you choose to install the GTS100  
yourself read all of the information in  
this manual before you start the installa-  
tion. Pay particular attention to the  
safety precautions and notes.  
Stealth Remote Silent Turn-On  
Circuitry with Power-On Indicator  
Continuously Adjustable Gain Controls  
Capable of Single-Ended Operation  
Into 2-Ohm Loads.  
It will save potential problems later if  
you take a few minutes to plan the com-  
plete installation before you start. The  
routing of wires, the power supply con-  
nection points, and the mechanical  
installation of the unit should be com-  
pletely thought out before you begin.  
Work carefully and check each step as  
it is performed. Before operating the  
amplifier, recheck the entire installation  
to be sure that each connection is cor-  
rect, properly insulated and secure.  
Fully Complementary, Direct-Coupled,  
Discrete Power Amplifier Circuitry  
Gold Plated RCA Input Connectors  
Preamp Output Capability  
Convenient Easy-Disconnect Power  
and Speaker Connections  
Third Order (18dB per Octave),  
Capacitive/Inductive Power-Supply  
Filtering  
Input Mode Switching  
Made in USA  
4
 
5. Connect the outputs from the signal  
source to the appropriate inputs of  
the amplifier according to the Wiring  
Diagram (page 13) with either high  
quality low-level signal cables with  
RCA plugs, with the supplied  
Speaker-level input connector, or  
both.  
Quick Start  
Recommended for experienced  
professional installers only!  
1. Disconnect the negative cable from  
the battery. Note: If the vehicle’s  
radio features a code type security  
system, make certain you know the  
code before disconnecting the  
battery!  
6. Connect the speakers to the ampli-  
fier according to the wiring diagram  
on page 13.  
2. Mount the amplifier to the desired  
location using four screws.  
7. Turn the input sensitivity adjustment  
to the 1/4 position.  
3. Run a minimum AWG #10 power  
cable complete with a 20 amp fuse  
(not included) directly from the posi-  
tive +12V battery terminal to the  
desired amplifier location. Keep  
the fuse to within 5" of the battery  
terminal, and before the wire runs  
through any metal partition.  
8. Set the input level switch to “line”  
if you are using the line-level  
(preamp) inputs.  
9. Set the crossover switch as desired.  
10. Set the input mode switch to  
stereo, left + right or right input  
only operation.  
Note: All wiring connections should be  
made either by soldering with heat-  
shrink tubing insulation or with high  
quality crimp type insulated connectors  
installed with a good crimping tool.  
Soldering crimp connections is recom-  
mended to further enhance connection  
reliability. Never use wire-nuts, insula-  
tion-displacement connectors (i.e.  
ScotchLok type), or “twist and tape”  
connections. Do not use electrical tape;  
it will loosen with age and extreme  
temperatures. Never leave bare wire  
exposed.  
11. Reconnect the negative battery  
cable.  
12. Turn on the signal source at a low  
volume level and check for the  
correct output from each speaker.  
13. Adjust the amplifier gain control,  
using the procedure described in  
the Gain Adjustment section on  
page 20.  
14. Read the rest of the manual to get  
maximum use and enjoyment from  
your amplifier.  
4. Connect power wiring as shown in  
the Wiring Diagram on page 13,  
using the supplied power harness.  
5
 
When the GTS100 is in bridged mode,  
the combined impedance of the speaker  
(or speakers) connected to the bridged  
channel should be at least 4 ohms. As  
in the example above, sustained opera-  
tion of the GTS100 in bridged mode  
with less than 4-ohms will likely cause  
overheating. If monaural operation is  
desired, and two 4-ohm speakers are  
used, it is best to connect each speaker  
to an individual amplifier channel and  
use the “L+R” mode on the input-mode  
switch to provide monaural operation.  
System Design Using the  
GTS100  
Speakers  
When used in the non-bridged mode,  
the GTS100 can easily drive 2 ohm  
speaker loads. When only one speaker  
is connected to each channel, virtually  
any common speaker may be used.  
When two speakers are connected in  
parallel to a given channel, each speaker  
must have a minimum impedance of at  
least 4 ohms to ensure that the com-  
bined load does not drop below 2 ohms.  
Although the amplifier will not be dam-  
aged, load impedances lower than 2  
ohms will eventually cause the amplifier  
to overheat, activating the protection  
circuits and causing the unit to shut off  
until it cools down sufficiently.  
The GTS100 must not be used with  
speakers that have either one of their  
input terminals wired to the frame of  
the speaker or to the chassis of the  
vehicle.  
Signal Sources  
The low level preamp outputs of any  
radio/tape deck, CD player or preamp/  
equalizer so equipped can drive the  
GTS100. The Gain control of the  
GTS100 is used to match the amplifier  
to the output voltage of the source.  
This matching is important to keep  
noise low and is explained in the Gain  
Adjustments section of this manual  
(page 20).  
Parallel Wiring  
(+)  
2 Ohms  
Nominal  
Impedance  
4 Ohms  
4 Ohms  
(-)  
Thanks to Universal Interface circuitry,  
the GTS100 can also be connected to  
power amplifiers, radios or equalizers  
that are equipped with only speaker  
outputs by connecting them through the  
speaker level input connector. Inside  
the GTS100, the speaker-level and  
preamp-level inputs are connected  
through a mixing circuit, which allows  
them to be used simultaneously.  
Series Wiring  
(+)  
4 Ohms  
8 Ohms  
Nominal  
Impedance  
4 Ohms  
(-)  
Therefore a low level source, such as  
a CD player equipped with preamp  
6
 
controls (Volume, Balance, Bass,  
Treble) may be connected to the pre-  
amp-level inputs at the same time as a  
powered radio/tape unit is connected to  
the speaker-level inputs. This provides  
a higher performance alternative to an  
FM Modulator connection when you  
wish to add CD capability to a factory  
installed cassette radio. Switching from  
one source to the other is as simple as  
turning the desired source on and turn-  
ing the undesired one off — no addi-  
tional switches or relay connections are  
needed.  
Other Components  
The system options of the GTS100  
are numerous. All JBL amplifiers are  
designed with sufficient adjustment  
range to match with the accepted “nor-  
mal” voltages and impedances used by  
virtually all car audio components. With  
very few exceptions, the GTS100 will  
match correctly to any equipment you  
already have.  
Typical Applications  
The following diagrams show the most common basic system configurations using the  
GTS100. More elaborate systems are formed by using a combination of these “building  
blocks.” For additional ideas, refer to the “Add On and Upgrade Section” near the end  
of this manual.  
Application 1  
Stereo Full-Range or Subwoofer Operation  
Preamp or  
Speaker-Level  
Input  
L
R
Full-Range Operation  
Crossover Input Mode  
Line  
Switch  
Switch  
Switch  
Off  
Stereo  
In  
GTS100  
Subwoofer Operation  
L– L+  
R– R+  
Crossover Input Mode  
Line  
Switch  
2 or 4-Ohm  
Switch  
Switch  
Full-Range  
Speakers or  
Low  
Stereo  
In  
Subwoofers  
+
+
Main speakers are driven by head unit or additional amplifier.  
7
 
Application 2  
R
Bridge-Mode Operation  
Preamp or  
L
Speaker Level  
Single Amplifier:  
Subwoofer-Operation (Mono)  
Amp Crossover Input Mode Line  
For Dual-Amplifier  
For Single Amplifier  
Subwoofer Use  
Switch  
Low  
Switch  
L + R  
Switch  
In  
Full-Range or Subwoofer Use  
B
R
L
R
Main speakers are driven by head unit or  
additional amplifier.  
Dual Amplifier:  
GTS100  
GTS100  
A
B
Subwoofer-operation (Stereo)  
Amp Crossover Input Mode Line  
Switch  
Switch  
Switch  
A+B  
Low  
R
In  
L– R+  
L– R+  
Full-Range Operation (Stereo)  
Amp Crossover Input Mode Line  
4-Ohm  
4-Ohm  
Full-Range  
Speaker or  
Subwoofer  
Full-Range  
Speaker or  
Subwoofer  
Switch  
Off  
Switch  
R
Switch  
In  
+
+
A+B  
Application 3  
Front  
Rear  
Bi-amplified, Three-channel  
Subwoofer/Satellite System.  
Preamp or  
Speaker-Level  
Input  
R
L
R
L
Amp Crossover Input Mode Line  
Switch  
Switch  
Switch  
A
B
High  
Low  
Stereo  
L + R  
In  
In  
GTS100  
GTS100  
B
A
R– R+  
L– L+  
L– R+  
Stereo Subwoofers may be used by configuring  
GTS100-B as shown in Application #1  
2 or 4-Ohm  
Full-Range  
Speakers  
4-Ohm  
Subwoofer  
+
+
+
Application 4  
Bi-amplified, System Using  
Preamp Output Capability  
Speaker-  
Level  
Preamp  
Output  
Preamp  
Input  
Input  
L
R
R
L
L
R
Amp Crossover Input Mode Line  
Switch  
Switch  
Switch  
GTS100  
B
GTS100  
A
B
High  
Low  
Stereo  
L + R  
Out  
In  
A
L– L+  
R– R+  
L– R+  
Stereo Subwoofers may be used by configuring  
GTS100-B as shown in Application #1 or  
by using dual GTS100s as shown in  
Application #2  
2 or 4-Ohm  
Full-Range  
Speakers  
4-Ohm  
Subwoofer  
+
+
+
8
 
wires, hydraulic brake lines, fuel  
lines, or fuel tanks that may be dam-  
aged while doing so. Such compo-  
nents may be hidden within double  
walled panels or structural mem-  
bers of the vehicle, so be extremely  
cautious.  
Installation Precautions  
Before beginning the installation of the  
amplifier, read the following precautions  
carefully. Failure to heed these warn-  
ings could result in personal injury or  
damage to property.  
• The GTS 100 should be installed  
only in vehicles that have 12-volt  
negative ground electrical systems.  
Connection to other types of electri-  
cal systems may damage the ampli-  
fier and/or the vehicle’s electrical  
system.  
• Do not bypass or modify the fuse on  
the chassis of the amplifier. Do not  
replace the fuse with one rated for  
higher current levels. Doing so could  
result in damage to the amplifier  
and the vehicle’s electrical system.  
Repeated blowing of the power  
supply fuse indicates a fault within  
the amplifier or problems in the  
installation.  
Before beginning the installation, dis-  
connect the negative (ground) cable  
from the vehicle’s battery. This will  
prevent accidental short circuits while  
working on the installation. Reconnect  
the cable only after the installation is  
complete and the wiring has been  
carefully checked to be sure there  
are no exposed wires or short circuits  
and everything is properly and  
• An additional power supply fuse (not  
included) should be located as close  
as possible to the battery on the  
+12V wire to minimize the chance of  
electrical system damage or fire in  
the event of a short circuit in the  
power supply wire.  
securely connected. Note: If the vehi-  
cle’s radio features a code type secu-  
rity system, make certain you know  
the code before disconnecting the  
battery!  
Physical Installation  
There are several factors to consider  
when selecting a mounting location for  
the GTS100.  
• Work in an area that is well ventilated.  
• It must be solidly mounted in a place  
where it will not be subjected to  
excessive shock and vibration.  
• Wear eye protection whenever cut-  
ting, drilling or filing any parts of the  
vehicle.  
• Under no circumstances should the  
amplifier be mounted where it will be  
exposed to moisture or extreme heat.  
• Wear ear protection when using high  
speed drills, saws, sanders, or  
grinders. We want you to be able to  
enjoy the system once it is installed.  
• Try to mount the amplifier where the  
main +12 volt power supply wire,  
which must be connected directly to  
the battery, can be kept relatively  
short.  
• Before cutting or drilling any holes in  
the vehicle, inspect the area carefully  
to be sure there are no electrical  
9
 
Controls and Connectors  
• The GTS100 must be mounted in a  
place where air can circulate around  
the fins on the chassis. Good air  
circulation around the amplifier will  
make it operate at lower tempera-  
tures and reduce the chance of the  
thermal protection circuits being trig-  
gered. The installation positions that  
provide the most efficient air circula-  
tion around the amplifier are shown  
below.  
1. Line Level RCA Inputs – Use these  
connectors for line (preamp) level input  
to the amplifier. When speaker inputs  
are used, this connector can be con-  
verted for use as a line-level output by  
setting the “Line” switch to “out.”  
2. Line Selector – This switch sets the  
line level connectors for either input or  
output. Set switch to “In” for normal line  
level input operation.” Set the switch to  
“Out” to use the line level connector for  
line level outputs to drive other ampli-  
fiers or signal processors when using  
the speaker level inputs.  
• Use a mounting location that allows  
access to the wiring connections and  
level adjustments. This allows the  
unit to be mounted before these con-  
nections and adjustments are made.  
If the amplifier must be mounted in  
an inaccessible location, it may be  
easier to mount it after the wiring  
connections and level adjustments  
are complete.  
3. Gain Control – Use this control to  
adjust the input sensitivity of the ampli-  
fier. See the “Gain Adjustments” section  
for tips on proper setup.  
4. Input Mode Selector – This switch is  
used to set the input mode for both pre-  
amp and speaker-level inputs. Set this  
switch to Stereo for normal operation  
using both left and right inputs. Set this  
switch to R to drive both the left and  
right channels with only a single input  
on the right channel. Set this switch to  
“L+R” to sum the left and right inputs  
for a mono output on both amplifier  
channels.  
BEST-Vertical Mounting  
AIR FLOW  
GOOD-Horizontal Mounting  
5. Speaker Input Connector – Use this  
connector for speaker level input sig-  
nals. A wire harness is supplied for  
this connector. See the “Audio Input  
Connections” section (page 15) for  
wiring instructions. This input also  
includes JBL’s Common Sense input  
circuitry which turns the amplifier on as  
soon as a high powered head unit con-  
nected to this input is turned on.  
AIR FLOW  
NEVER-Mount Upside Down  
10  
 
LINE  
INPUT MODE  
SPEAKER  
INPUTS  
CROSSOVER  
OFF HIGH  
SPEAKER  
OUTPUTS  
+
R
IN  
OUT  
R
L
FUSE 20A  
NOM  
+
+
+
+
20A  
R
L
L
R
L
STEREO  
LOW  
BAT(+) REM GND  
-
-
-
-
MIN MAX  
GAIN  
POWER  
R
BRIDGED  
Fuse  
Line Level RCA Inputs  
Line Selector  
Battery Ground  
Gain Control  
Power  
Connector  
Remote Turn-On  
Input Mode  
Speaker Input Connector  
Crossover Mode Selector  
Battery (+) In  
11  
Speaker Output Connector  
POWER  
Power Indicator  
on page 14 and the wiring diagram on  
page 13 for information on wire color  
codes and proper connections.  
6. Crossover Mode Selector – This  
switch controls the built in crossover.  
Set the switch to “Off” for full band  
operation. Set this switch to “Low” to  
activate the 80Hz low pass filter on the  
amplifier (for subwoofer use). Set the  
switch to “High” to activate the 100Hz  
high pass filter for use with satellite  
speakers. Note that the filter does not  
affect the line level outputs on the  
amplifier.  
11. Speaker Output Connector –  
Connection for included speaker output  
harness. See “Speaker Connections”  
section on page 17 for information on  
wire color codes.  
12. Power Indicator LED – Power indi-  
cator light glows for normal operation  
when the amplifier is activated by either  
the remote or common sense turn-on  
circuits.  
7. Fuse – 20 Amp ATC type Fuse.  
8., 9., 10. Power Connector –  
Connection for included power wire har-  
ness. See “Power Supply Connections”  
11  
 
Mounting Instructions  
Wiring  
Proper wiring of the GTS100 and the  
associated components is extremely  
important for proper performance and  
long term reliability. Using the proper  
type of wire is very important. If a spe-  
cific type of wire should be used for a  
certain application, it will be noted.  
Place the amplifier in the installation  
location. Use a pen or pencil to mark  
the four mounting screw hole locations.  
Set the amplifier aside and drill the  
holes for the mounting screws. (Note: If  
the surface you are mounting the amp  
to is covered with carpeting or uphol-  
stery, cut a small “x” in the material at  
each screw hole location before drilling  
the holes. This will help prevent tearing  
or stretching of the material and carpet  
fibers from being pulled out.) Set the  
amplifier in position and align the  
mounting holes with the holes previously  
drilled. Put washers on the four sheet  
metal screws provided and drive them  
into the mounting panel. Tighten the  
screws evenly until the unit is solidly  
mounted.  
All wiring connections should be made  
either by soldering with heatshrink tub-  
ing insulation or with high quality crimp  
type insulated connectors installed with  
a good crimping tool. Soldering crimp  
connections is recommended to further  
enhance connection reliability. Never  
use wire-nuts, insulation-displacement  
connectors (i.e. ScotchLok type), or  
“twist and tape” connections. Do not  
use electrical tape; it will loosen with  
age and extreme temperatures. Never  
leave bare wire exposed.  
Route the wiring through the car care-  
fully. Do not allow wires to lay against  
sharp sheet metal edges or any other  
surfaces that might wear away or cut  
through the insulation of the wire. Use  
insulated strain reliefs, rubber grom-  
mets and plastic tubing to protect the  
wires whenever they are run through  
sheet metal panels or are placed where  
they might be pulled or damaged.  
12  
 
Typical System Configuration  
Cassette/CD Tuner  
Speaker Level Output Connection  
(Use only when line level ouput  
is not available)  
Cassette/CD Tuner  
(Head Unit)  
CD Player  
or Changer  
Antenna Input  
CD Input  
Power  
Antenna  
Cassette/Receiver  
Power Supply  
Wires  
Cassette/CD Preamp Output  
Power  
Antenna  
Relay  
Amplifier  
Power  
Connection  
G
T
S
1
0
0
POWER  
Amplifier  
Speaker  
Level  
Amplifier  
Speaker  
Output  
Input  
Connection  
+
+
Speakers  
Blue w/White Stripe - Remote On/Off  
Ignition Switch  
20 Amp  
(Not Included)  
Yellow  
Main +12V  
Fuse  
+
Vehicle Battery  
Black - Power Ground  
Chassis Ground  
13  
 
Ground Wire (Black)  
Power Supply Connections  
• Proper grounding is extremely impor-  
tant. It has a significant effect on the  
overall performance and noise level  
of the system. The ground wire must  
be solidly connected to a major sheet  
metal structure of the vehicle. Usually  
the power supply ground wire can be  
connected to a sheet metal panel  
near the amp mounting location.  
Scrape all paint and primer off the  
sheet metal at the grounding point to  
ensure a good electrical connection.  
Attach the wire to the grounding point  
with a sheet metal screw and lock  
washer (preferably a star lock washer)  
or a bolt/lock washer/nut set.  
The power input and remote turn-on  
wires are connected to the GTS100 via  
the power connector on the end of the  
amplifier. Use the included wire harness  
for connections. In some cases, such  
as a custom competition installation,  
you may wish to make your own custom  
power harness. The part number of the  
mating connector and terminals is listed  
in the specifications section of the man-  
ual, and is a common part available at  
many electronics parts retailers. Please  
do not call JBL for this, we stock only  
the pre-made harness as supplied with  
the amplifier.  
• In some vehicles, such as those  
that have non-metal bodies, it may  
be necessary to extend the power  
supply ground wire and connect it to  
a frame rail or even directly to the  
negative (-) terminal of the battery.  
Use heat and oil resistant 10 gauge  
or larger stranded copper automotive  
wire and crimp or solder and insulate  
the wire-to-wire connections. Keep  
the extension wire as short as possible.  
Solder or crimp a terminal on the end  
of the extension wire and connect it  
to the frame or battery terminal.  
+12V Battery Wire (Yellow)  
• Connect the yellow wire directly to  
+12 volt terminal of the battery.  
• If it is necessary to extend the power  
wire, use 12 gauge or larger wire that  
is heat and oil resistant.  
• The GTS100 will draw as much as  
20-Amps from the vehicle’s electrical  
system, enough to overload conven-  
tional vehicle wiring. Therefore the  
+12 volt power supply must be  
directly from the positive side of the  
battery. Do not connect to the  
vehicle’s fuse block or to a wire  
feeding other accessories.  
• When multiple amplifiers are installed  
in the system, it is often best to  
ground all of the amplifiers and signal  
processors to the same point to pre-  
vent noise pickup from a ground  
loop. In some unusual installations  
the noise level will be lower if the  
amplifier or amplifiers are grounded  
to the same point that the head unit  
is grounded. Use of heavy gauge  
• To prevent electrical system damage  
or fire, a fuse holder and fuse (not  
included, maximum 20A) must be  
installed in the power supply wire, as  
close to the battery as possible, and  
before the wire travels through the  
firewall or other metal panel.  
14  
 
wire for all grounding, even signal  
processors and head units, can also  
help to minimize possible noise  
pickup.  
on and off with the vehicle’s ignition  
switch. The remote on/off system draws  
negligible current so a relatively small  
(18 or 20 gauge) extension wire may be  
used. Be sure to securely crimp or sol-  
der and insulate the wire-to-wire con-  
nections.  
Remote Turn-On Wire (Blue with  
White Stripe)  
Because the JBL GTS100 includes  
Common Sense 2-way turn-on  
Audio Input Connections  
circuitry, you have two options for  
remotely activating the amplifier. When  
using the speaker level inputs with a  
head unit that includes a BTL power  
amp it is not necessary to connect the  
remote wire. The amplifier will automati-  
cally activate whenever you turn on the  
head unit. If the head unit is not of the  
high power BTL type, Common Sense  
will not work. You will need to connect a  
remote wire as discussed below. If you  
are using the line level inputs follow the  
remote wire connections listed below.  
Line Level Input Connection  
Proper wiring between the signal  
source, any other components in the  
system and the GTS100 will help to  
keep noise levels in the system low.  
Use high quality, low capacitance  
shielded wire. Keep the wire as short  
as possible. Do not splice shielded  
wires together. Do not run audio signal  
wires alongside power wires either for  
the amp or the vehicle’s standard  
power wires. When wires are run for  
long distances, separate the audio sig-  
nal 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 per-  
pendicular. Avoid routing any wires  
near accessories such as ignition con-  
trol modules, tachometers, fuel pumps  
or fan motors.  
The remote power control system turns  
the GTS100 off when not in use to pre-  
vent discharging of the vehicle’s bat-  
tery. When +12 volts is applied to the  
remote wire the amplifier is turned on. A  
red LED on the end panel of the ampli-  
fier lights whenever the amplifier is on.  
If the head unit has a +12 volt automatic  
antenna or amplifier remote activation  
wire, connect it to the blue/white wire of  
the GTS100.  
The line level inputs of the GTS100  
accept standard phono plugs (also  
called RCA plugs.) The outputs of most  
head units, equalizers or crossovers  
also accept RCA connectors. 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.  
Some head units have no automatic  
antenna or power amp activation wire.  
Other decks have automatic antenna  
wires that are “on” only when the radio  
is used (the +12 volt signal is off when a  
tape is played.) In such cases, connect  
the remote turn-on wire to an unused  
accessory terminal in the fuse block, or  
any other +12 volt source that is turned  
15  
 
NOTE: The GTS100 has a built-in  
outboard crossover, use the “R” mode  
and connect your source input to the  
right channel input.  
80Hz low pass (subwoofer) crossover and  
a 100Hz high pass (satellite) crossover.  
Be sure the crossover switch is properly  
set for the chosen system configuration  
(See the “Typical Applications” section  
for suggestions). If you have any ques-  
tions about how to set this switch, con-  
tact your local JBL dealer.  
Simultaneous Stereo + Mono – For this  
connection, the Input Mode switch is left  
in the stereo position. Main speakers  
are connected normally to the left and  
right stereo outputs, and a center-  
channel or subwoofer speaker is con-  
nected in bridged mode. Refer to the  
diagram on page 19 in the “Speaker  
Connections” section for details.  
Input-Mode Switch  
This switch is set according to the num-  
ber of input channels connected to the  
amplifier and the desired mode of oper-  
ation. See diagrams on pages 7 and 8  
and the descriptions below for options.  
Speaker Level Input Connections  
When speaker level signal is used to  
drive the GTS100, the signal goes into  
the amp through a special four 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. Keep the  
wiring inside the passenger and trunk  
compartments and make the wires as  
short as possible. All connections  
should be securely crimped  
Standard Operation – When using the  
GTS100 as a conventional stereo  
amplifier simply connect the preamp-  
level source outputs directly to the two  
gold RCA connectors or connect the  
head unit speaker outputs to the  
speaker-level inputs with the input  
mode switch set to “stereo.” When  
using two sources, both the speaker  
and preamp-level inputs may be used  
simultaneously. Be sure to maintain left  
and right channel consistency.  
or soldered and insulated with  
heatshrink tubing.  
Bridged Mode Operation – To select  
bridge mode operation, set the input  
mode switch in either the “R” only or  
“L+R” position. In the “R” position, sig-  
nal from the right channel input is fed to  
both amplifier channels. In the “L+R”  
position, the signal from both channels  
is summed internally. When using a sin-  
gle GTS100 for mono mode fed with a  
stereo signal it is best to use the “L+R”  
mode. When using a GTS100 for each  
channel, or when feeding a single  
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 con-  
nected to the left positive input of the  
GTS100. The color code for the speaker  
level input harness is as follows:  
GTS100 with a mono signal from an  
16  
 
Speaker Level Input Color Codes  
Dual Source Remote Wiring diagram.  
Left (+):  
Left (-):  
White  
1N4001  
Diode  
From Head  
Unit #1  
Remote or  
Antenna Output  
White with Black Stripe  
Gray  
Right (+):  
Right (-):  
To  
GTS100  
Remote  
Gray with Black Stripe  
Using Both the Speaker Level Input  
and Line Level Input Together  
1N4001  
Diode  
From Head  
Unit #2  
Remote or  
Antenna Output  
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  
GTS100. You may simultaneously con-  
nect a CD player equipped with preamp  
volume control to the preamp-level  
inputs of the GTS100. The Universal  
Interface circuitry of the GTS100 will  
isolate the inputs from each other while  
mixing both signals. Therefore switch-  
ing 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.  
Speaker Connections  
When connecting speaker wires, be  
sure that no uninsulated wire remains  
exposed and no loose strands of wire  
touch either an adjoining wire, terminal  
or a metal surface. Securely crimp or  
solder all connections and insulate  
them with heatshrink tubing.  
Use high quality 18 gauge or larger  
speaker wire for the amplifier to speaker  
connections. Larger wire or special high  
performance speaker cables may  
improve the performance of some  
systems.  
Be very careful when speaker wire is  
routed through a door hinge area to  
door mounted speakers. Use grommets  
and strain reliefs wherever necessary to  
prevent damage to the wires.  
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 and is con-  
nected to the speaker level inputs. The  
Common Sense turn-on circuit will acti-  
vate the GTS100 when a powered  
source is used, and the conventional  
remote connection of the preamp-level  
source will activate the amp when it is  
used.  
The proper speaker connection  
depends on whether the GTS100 is  
used bridged or stereo. The speakers  
are connected to the amplifier with the  
included wire harness. If you wish to  
purchase the raw connector to make a  
custom-length harness, the part number  
is listed in the Specifications section.  
This item is commonly available from  
local electronic parts distributors.  
17  
 
Please do not call JBL for this part; we  
stock only the harness assemblies as  
supplied with the amplifier.  
same time. This is sometimes used for  
center-channel applications or for inex-  
pensive subwoofer addition, essentially  
creating a 3-channel system. However,  
unlike a true bi-amplified subwoofer  
connection, this system configuration  
does not provide for control of sub-  
woofer-satellite balance, it requires the  
use of a passive subwoofer crossover  
instead of the superior active circuitry  
already built-in to the GTS100, and it  
does not separate the power amps  
driving the satellites from the amps  
driving the subwoofer. Therefore this  
connection is best used for addition of  
a center-channel, or as an interim step  
as you build up to a true bi-amplified  
subwoofer-satellite system. Connect the  
main pair of stereo speakers as in the  
stereo mode, connect the mono speaker  
as described above for bridge-mode  
connection (see diagram on page 19).  
For use in center channel applications,  
a high-power “L-Pad” or power fader  
can be used to attenuate the center  
channel for proper level matching. For  
subwoofer-satellite use, connect a non-  
polarized capacitor in series with each  
main speaker, and a high-power inductor  
(coil) in series with the subwoofer. Your  
authorized JBL dealer will help you  
choose the correct values for your par-  
ticular components. The input-mode  
switch should be set to “STEREO”.  
To get proper bass response and  
stereo imaging, all the speakers in the  
system must be “in phase.” The inputs  
terminals of the speakers will be marked  
in some way to identify positive and  
negative polarity. Make sure that the  
positive (+) speaker terminal is attached  
to the positive (+) amplifier connection  
in every speaker-to-amp connection. All  
two conductor speaker wire has one  
conductor marked in some way so it  
can be easily traced.  
The speaker output wire harness color  
codes are listed below:  
Speaker Output Color Codes  
Left (+):  
Left (-):  
White  
White with Black Stripe  
Gray  
Right (+):  
Right (-):  
Gray with Black Stripe  
Stereo Connection – Connect each  
speaker directly to the speaker output  
harness according to the color-code  
listed above. The input-mode switch  
should be set to “STEREO”  
Bridged-mode Connection – Connect  
the loudspeaker positive (+) terminal to  
the RIGHT channel positive wire (Gray).  
Connect the loudspeaker negative (–)  
terminal to the LEFT channel negative  
wire (White with Black stripe). The  
input-mode switch should be set to “R”  
or “L+R”.  
Simultaneous Stereo + Mono  
Connection – The GTS100 may be  
used to drive a stereo pair of speakers  
with a mono (bridged) speaker at the  
18  
 
Subwoofer (Low Pass)  
Simultaneous Stereo-Mono  
Connection Diagrams  
A. Satellite/Subwoofer  
(+)  
(–)  
Component Values for  
4 Ohm Loudspeakers*  
Tweeter/Midrange Satellites  
(High Pass)  
High Pass Satellite  
Crossover Frequency: 100Hz  
Right  
Left  
(+)  
C
(+)  
C
(–)  
(–)  
C: 300µF Capacitor  
L
100V, Non-Polorized  
Subwoofer Low Pass  
Crossover Frequency: 100Hz  
L: 6.2mH Air Core Inductor  
LINE  
INPUT MODE  
SPEAKER  
INPUTS  
CROSSOVER  
SPEAKER  
+
IN  
OUT  
R
L
R
OFF  
HIGH  
OUTPUTS  
FUSE 20A  
20A  
NOM  
+
+
+
+
R
L
L
R
L
STEREO  
LOW  
BAT(+) REM GND  
-
-
-
-
MIN MAX  
GAIN  
POWER  
R
BRIDGED  
*You may scale the 100Hz values listed to a different desired frequency by using the following formulas:  
100  
High-Pass:  
x 300µF = New Capacitor Value  
desired frequency in Hz  
100  
Low-Pass:  
x 6.2mH = New Inductor Value  
desired frequency in Hz  
Center Channel  
Bridged Speaker Connection*  
B. Center Channel  
(+)  
(–)  
8 Minimum  
8 L-Pad  
(Optional But Recommended)  
LINE  
IN  
INPUT MODE  
SPEAKER  
INPUTS  
CROSSOVER  
OFF HIGH  
SPEAKER  
+
OUT  
R
L
R
OUTPUTS  
FUSE 20A  
NOM  
+
+
20A  
+
+
R
L
L
R
L
STEREO  
LOW  
BAT(+) REM GND  
-
-
-
-
MIN MAX  
GAIN  
POWER  
R
BRIDGED  
* Center Channel Speaker Minimum 8 Ohms, Main Speakers  
Minimum 4 Ohms When Used Simultaneously.  
(+)  
4 Minimum  
(+)  
(–)  
(–)  
Stereo, Non-Bridged  
Speaker Connection*  
4 Minimum  
19  
 
carefully to the system output, adjust  
the volume control of the radio/tape  
deck to the point where you first begin  
to hear audible distortion. Reduce the  
level just to the point where the distor-  
tion goes away. This is the maximum  
undistorted output level of your head  
unit and signal processors, and should  
not be exceeded during use. If audible  
distortion does not occur, continue to  
increase the level until the head unit is  
turned all the way up. If this setting  
does not provide adequate volume lev-  
els, gradually increase (turn clockwise)  
the gain control of the GTS100 until the  
system plays as loud as necessary or  
when the first signs of distortion are  
heard.  
Operation  
Before operating the GTS100, recheck  
all wiring connections to make sure they  
are correct and secure. Be sure that a  
20 amp fuse (not included) is installed  
in the +12V line next to the battery.  
Reconnect the negative ground (–)  
terminal of the battery. Make sure  
that the input mode selector, crossover  
switch and preamp mode switch are  
properly set.  
Gain Adjustments  
The setting of the gain control on the  
GTS100 is important to ensure proper  
performance, low noise levels, and  
maximum reliability in the system. As a  
general rule, controls on components at  
the front-end of the system (Source,  
equalizers, electronic crossovers, etc.)  
should be set as high as possible, with  
the amplifier gain control set as low  
as possible while still providing ade-  
quate volume levels. Using a high sig-  
nal level from the source and a low  
gain setting on the amplifier will help  
keep background noise levels in the  
system low.  
When multiple amplifiers are used in  
the system, it is best to adjust the gain  
of the amplifier driving the main (usually  
front) speakers first. Then turn down the  
head unit’s volume control to a comfort-  
able level, and adjust the remaining  
amplifiers for the desired system bal-  
ance. You will find this easiest to do by  
adjusting the amplifiers in the following  
order: 1) front-channels, 2) rear-chan-  
nels, 3) subwoofers. Complex systems  
incorporating tri-or quad-amplification  
can be time consuming to adjust. Your  
local authorized JBL installation special-  
ist is the best person to help with such  
adjustment.  
To adjust a system using a single  
amplifier, start with the amplifier input  
sensitivity controls fully counterclock-  
wise. Some radio/tape decks have addi-  
tional output level controls or switches.  
Set those to their maximum position.  
Set the level controls on any associated  
equipment such as equalizers and  
electronic crossovers to the maximum  
position or as recommended by the  
manufacturer. Set all Bass/Treble or  
equalizer controls to their centered or  
bypassed positions. While listening  
Other Characteristics  
Turn-On Delay – When installed as  
described in this manual, the GTS100  
will turn on and off with the head unit or  
the vehicle’s ignition switch. When the  
amplifier is turned on, there is a time  
delay of several seconds (longer in cold  
20  
 
weather) before the amplifier will pro-  
duce sound. This eliminates the chance  
of annoying noises produced by the  
radio or signal processors being ampli-  
fied and passed to the speakers when  
the system is first turned on.  
and 16 volts. Check that the power  
wires are not reversed.  
If the GTS100 is operated at very high  
power levels in a high ambient tempera-  
ture situation, the unit may not be able  
to radiate all the heat generated by  
such operation. If the temperature of  
the amplifier reaches a level that could  
cause damage, the thermal overload  
protection circuit will turn the amplifier  
off. It will turn the amp back on again  
when it cools off. Repeated activation of  
the protection circuits indicates that the  
system is being improperly operated or  
that the amplifier should be relocated to  
an area that either has a lower ambient  
temperature or that allows more air cir-  
culation around the unit.  
Power Consumption – Operating the  
GTS100 when the vehicle is not running  
may discharge the battery. Under nor-  
mal operating conditions, the units will  
draw an average of 5 amps from the  
battery. At high volumes, the amplifier  
can draw as much as 20 amps for brief  
bursts. After even a short period of  
time, this current drain can discharge  
the battery to the point that it will not  
start the vehicle. Power consumption  
under “no signal” conditions is less than  
1 amp for the GTS100. Even this small  
power usage can discharge a battery  
over several hours time. When the  
GTS100 is turned off, there is no cur-  
rent drawn from the battery despite the  
direct-to-battery power connection.  
Fuse Replacement – If the fuse on the  
GTS100 must be replaced, DO NOT  
use a fuse rated for higher current lev-  
els. The fuse size for the GTS100 is 20  
amps. Exceeding the standard fuse size  
or bypassing the fuse holder will void  
the warranty and may cause serious  
damage. It is extremely rare for this  
fuse to blow. If it blows repeatedly, it is  
most likely that the amplifier has an  
internal problem that will need to be  
repaired by an authorized service cen-  
ter. The only external cause for this  
fuse to blow is reversed polarity of the  
power wire connections.  
Overload Protection – The GTS100  
incorporates elaborate protection cir-  
cuitry to prevent damage to the ampli-  
fier circuitry and ensure reliable opera-  
tion. This circuitry will turn the amplifier  
off in the event of overheating, a short  
circuit on the speaker output wiring, or  
improper power supply connections. If  
the amplifier cycles on and off, or does  
not work at all, a problem in installation  
or an abnormal electrical condition is  
indicated. Check speaker wiring for  
short circuits or impedance loads signif-  
icantly below 2 ohms, (4 ohms in  
Solving Noise Problems  
The power supply system of every vehi-  
cle has some electrical “noise” that is  
generated by the ignition system, the  
alternator, the accessories, and their  
wiring. High performance audio equip-  
bridged mode). Check the power supply  
voltage at the input of the amplifier to  
be sure that it is normal, between 11  
21  
 
ment is more likely to pick up such  
noise than conventional equipment  
because it has wide frequency band-  
width and high gain (amplification) cir-  
cuits. The GTS100 has built-in power  
supply filters to help prevent noise prob-  
lems. If noise occurs it is probably the  
result of improper installation. The  
following suggestions will help you  
eliminate most noise problems.  
the amplifiers and signal processors are  
all grounded to the same point on the  
chassis. Usually the head unit does not  
need to be grounded to the same point  
as the rest of the system, but in some  
instances grounding the head unit to  
the same point will also help. If this  
does not adequately reduce the noise  
level, try another ground point on the  
car frame. Some ground points may  
work better than others. In some in-  
stances with plastic-bodied vehicles,  
grounding the source unit and/or  
amplifier directly to the battery will  
provide the best results, although,  
usually, this provides the worst results  
with most cars.  
Source Noise – Often noise in a system  
is picked up by the signal source.  
Before attempting to eliminate noise  
from the “amp” be sure it is not being  
picked up by the signal source and then  
passed on to the amp. To do this, con-  
nect the signal source output to an  
external amplifier which has no other  
connection to the vehicle except for the  
audio signal leads. A battery-powered  
portable with line-inputs works well for  
this. Listen to see if the noise is present  
in the signal from the source unit. If so,  
consult the manufacturer of the source  
unit, or your JBL dealer, for help in elim-  
inating this noise. If there is no noise in  
this signal, it can be eliminated as the  
source of the noise in your system.  
In complex systems involving compo-  
nents from different manufacturers, it  
helps to know the type of power sup-  
plies used in each component. For  
low-level signal processors such as  
equalizers or electronic crossovers, a  
manufacturer may either use a power  
supply which is isolated through a DC-  
to-DC converter, or a simple regulated  
supply from the +12V vehicle battery.  
Components using the latter type of  
supply can be identified by a direct con-  
nection from power ground to the shield  
of the RCA jacks (measured with no  
other connections present). For these  
components, the best ground connec-  
tion may be one where the power  
ground wire is not connected at all! The  
RCA cables will provide the ground  
connection to the source unit. Please  
note that this is only appropriate for  
units which draw less than 500mA of  
current. Higher power units of this type  
are best connected with their ground  
Ground Loops – The vast majority of  
noise problems in car audio systems  
are caused by inadequate or improper  
grounding. The head unit, the amplifier  
and any other components must be  
grounded to a major metal member of  
the vehicle’s frame. Make sure to  
choose a solid metal ground point. In  
many new vehicles some structural ele-  
ments are made of plastic.  
Although not usually necessary, practi-  
cal experience shows that often the  
noise level in the system will be lower if  
22  
 
wires connected directly to the chassis  
of the head unit. The trickiest grounding  
task is created when some components  
of this type are mixed with other compo-  
nents using isolated supplies. For this  
type of system, the following grounding  
scheme will usually work:  
must cross, they should cross at right  
angles. If you suspect that power line  
noise is being induced in the signal  
leads, you can repeat the test for  
source noise described previously, but  
perform the test at the amplifier end of  
the signal cables.  
1. Connect the head unit chassis to a  
solid vehicle ground using a short,  
heavy gauge wire (>AWG10). Do not  
connect this to the vehicle’s wiring  
harness, but go directly to a metal  
part of the vehicle.  
Other Noise Sources – Common noise  
problems will be solved by proper  
grounding and power supply connec-  
tions. However, there are many noise  
suppression devices (such as spark  
plug and coil lead suppressers and  
rotor and coil bypass capacitors) avail-  
able at auto parts or car stereo stores.  
There are also noise suppressers that  
can be connected directly to the alter-  
nator that are effective in some situa-  
tions. The use of any such suppressors  
should be discussed with a JBL autho-  
rized installation specialist. Certain  
vehicles are particularly “noisy,” espe-  
cially models that have solid state igni-  
tion systems or that have non-metal  
bodies. Such vehicles may require elec-  
trical noise suppression devices which  
are not normally needed.  
2. Connect all non-isolated signal-  
processor grounds directly to the  
head unit chassis at the same point.  
Run each wire individually. Due to  
wire resistance connecting multiple  
wires to a single wire, then running  
the single wire to the head unit, is not  
the same!  
3. Connect all amplifier and isolated  
signal processor grounds directly to  
the vehicle chassis at the same point  
as each other, but not necessarily to  
the same point as the head unit.  
Power-line Noise – The built-in power  
supply filter of the amplifier makes  
external filters unnecessary. In some  
cases, power supply noise can enter  
the system through the head unit power  
supply or the supply of an equalizer or  
other signal processor. Putting a filter  
on the head unit or signal processor  
power supply input may then be helpful.  
Antenna – A common noise problem is  
generated by a “ground loop” produced  
by the antenna shielded cable being  
grounded at both the antenna mounting  
point and at the head unit input. In this  
instance, insulate the antenna ground  
from the chassis of the vehicle at the  
antenna mounting point so the antenna  
shield is grounded only at the radio’s  
antenna input. Commercial antenna  
ground-loop isolators are also available.  
Power wires carrying high currents may  
induce noise in nearby signal wires.  
Make sure that power wires and signal  
wires do not run together for long dis-  
tances. When power and signal leads  
Switching Noise – The GTS100 has a  
highly developed switching power sup-  
ply which generates some RF interfer-  
23  
 
ence as a result of its switch-mode  
operation. Although this is internally  
filtered and shielded by the GTS100  
chassis, some unusually sensitive  
installations may pick up switching  
noise, especially when listening to weak  
AM radio stations. If this unusual situa-  
tion occurs, one of the following installa-  
tion corrections will typically eliminate  
the problem. 1) Relocate the amplifier  
to a position farther away from the radio  
or radio antenna. 2) Move the electrical  
ground of the head unit and/or amp to a  
different point on the vehicle’s chassis.  
3) Keep the amplifier power supply  
wiring away from the radio or antenna  
wiring. 4) Wrap the +12 volt power sup-  
ply wires for the radio/tape deck with  
metallized shielding tape or ground  
braid and ground the tape to the chas-  
sis of the vehicle.  
Additional System  
Configurations for Add-On  
or Upgrade  
The features and capabilities of the  
GTS100 provide tremendous system  
design flexibility. The diagrams on the  
following pages illustrate some of the  
system possibilities. They are in order  
of increasing complexity, showing the  
way a system may be upgraded in  
logical steps. Although the systems are  
shown using speaker-level connection  
from the head-unit, they may be built  
using any combination of speaker or  
preamp level inputs, depending on the  
capability of your head unit. (See  
pages 25-26.)  
Maintenance  
The GTS100 does not require any regu-  
lar maintenance. Periodically checking  
the main power supply and grounding  
points and terminal connections is  
advisable. Be sure the connections are  
solid and corrosion-free. Loose or cor-  
roded connections can cause annoying  
intermittent noise or unusual opera-  
tional problems. Do not allow dust to  
accumulate on the amplifier heat sinks.  
It will reduce the amplifier’s ability to  
dissipate heat. Occasional vacuum  
cleaning will prevent dust accumulation.  
24  
 
System 1  
Add Power to Main Speakers  
Front Outputs  
Rear Outputs  
Add a GTS100 to the main  
(usually front) outputs of  
an existing head unit.  
Secondary speakers  
(usually rear-fill) connect  
to the head unit's internal  
amplification.  
GTS100  
Next Step:  
Front  
Rear  
Full-Range  
Speakers  
Add a second GTS100 to  
amplify the other set of  
Full-Range  
Speakers  
L– L+  
R– R+  
L– L+  
R– R+  
speakers or a subwoofer  
(see System 2).  
+
+
+
+
System 2A  
Add a Subwoofer (Active)  
Front Outputs  
Rear Outputs  
Use the GTS100 to drive 1 or 2  
subwoofers with the head unit  
powering the main speakers.  
This is an excellent way to  
GTS100  
upgrade a good stock system.  
Next Step:  
Add power to Front Full-Range  
Speakers (see system 3).  
Front  
Full-Range  
Speakers  
Rear  
Full-Range  
Speakers  
L– L+  
R– R+  
L– L+  
R– R+  
+
+
+
+
+
1 or 2  
Subwoofers  
System 2B  
Add a Subwoofer (Passive)  
Front Outputs  
Rear Outputs  
Use the GTS100 in  
Simultaneous Stereo +  
Mono mode to drive main  
speakers with subwoofers.  
A passive crossover is  
needed for this as described  
on page 18.  
GTS100  
Next Step:  
Rear  
Add a second GTS100 to  
power subwoofers and  
main speakers individually  
Front  
Full-Range  
Speakers  
Speakers  
L– L+  
R– R+  
L–  
L+  
+
R–  
R+  
+
+
(see system 3).  
+
+
Subwoofer  
25  
 
System 3  
Add a Second GTS100  
Front Outputs  
Rear Outputs  
Preamp output to preamp input  
Get more power and system  
control by adding a second  
GTS100 to power the main  
speakers and subwoofers  
individually. Use the built-in  
crossover to high-pass the  
front speakers and low-pass  
the subwoofers.  
Next Step:  
Add power to the Rear Full-  
Range Speakers.  
Note: For Non-Fading  
bass, also connect the  
rear-channel head unit  
speaker output to the  
speaker level input of the  
subwoofer GTS100.  
GTS100  
GTS100  
Rear  
Full-Range  
Speakers  
Front Satellite  
Speakers  
L– L+  
R– R+  
L– L+  
R– R+  
+
+
+
+
+
1 or 2  
Subwoofers  
System 4  
Add Power to the Rear  
Front Outputs  
Rear Outputs  
Preamp output to preamp input  
Add an amp for the rear  
speakers for higher volume  
capability and more control.  
GTS100  
GTS100  
GTS100  
Next Step:  
Add more subwoofer power.  
Front Satellite  
Speakers  
Rear Satellite  
Speakers  
L– L+  
R– R+  
+
+
L– L+  
R– R+  
+
+
+
1 or 2  
Subwoofers  
System 5  
Add a Second  
Subwoofer Amplifier  
Front Outputs  
Rear Outputs  
Preamp output to preamp input  
For the ultimate in  
bass output, add a  
second subwoofer  
amplifier for a total  
system power of  
340 Watts RMS!  
GTS100  
GTS100  
GTS100  
GTS100  
Note the cross-  
Front Satellite  
Speakers  
Rear Satellite  
Speakers  
linking of preamp  
Subwoofers  
inputs for the two  
L– L+  
R– R+  
L–  
L+  
+
R–  
R+  
+
+
+
subwoofer  
+
+
amplifiers to  
provide non-  
fading bass.  
Next Step:  
Add additional amplifiers in bridge-mode to the front and  
rear main speakers. Then add electronic crossovers and biamp  
front and rear speakers.  
26  
 
In Case of Difficulty  
Power-on light does not come on.  
Head unit not on; turn the head unit on.  
Ground wire is disconnected or  
defective; check for continuity with an  
ohmmeter between the GTS100’s  
ground terminal and a known chassis  
ground point.  
Battery wire is disconnected or  
defective; check for approximately  
+12 volts between the GTS100’s  
Battery and Ground terminals.  
Blown fuse; check the GTS100’s  
20 amp fuse located on the endpanel  
near the power connector. If it is blown  
replace it with an identical one. If the  
new fuse blows immediately, then check  
all the wiring connections. If no fault is  
found, consult your JBL dealer.  
Remote-on wire between the head unit  
and the GTS100 is disconnected or  
defective; check for +12 volts between  
the GTS100 remote on wire and the  
ground wire with the head unit on.  
Head unit connected to speaker-level  
input is not BTL high-power type and no  
remote wire is connected; connect  
remote turn-on wire to switched +12V  
source.  
Remote-on light is illuminated, but no  
sound is heard from some or all of the  
speakers.  
Incorrect switch settings; make sure  
that all switches (input mode, line, and  
crossover) are in their correct positions  
for your system configuration.  
Incorrectly connected or shorted  
speaker wires; check for shorts in  
wiring.  
Defective or disconnected audio cables;  
check for continuity and replace if  
necessary.  
27  
 
(continued)  
Remote-on light is illuminated, but no  
sound is heard from some or all of the  
speakers.  
Incorrect gain adjustment; verify that  
the GTS100 gain controls are not  
turned completely down. If they are,  
sound output level may be very low  
and may give the impression that the  
system (or part of the system) is dead.  
Defective head unit or signal processor;  
check each component for proper  
wiring and operation.  
Defective GTS100; If there is audio  
signal present at the inputs of the  
GTS100 and there is no output, the  
GTS100 may be defective.  
Alternator whine through the audio  
system with the engine running.  
Ground loops; Follow the wiring  
suggestions in the section called  
“Solving Noise Problems.” Also, verify  
that the chassis grounding point you  
have chosen is true ground by checking  
for continuity between the chassis  
ground point and battery ground.  
Bass output from speakers too low.  
Speaker wired out of phase; check for  
proper polarity on all speaker wiring  
(+ amp terminal to + speaker terminal  
and – amp terminal to – speaker  
terminal.  
If you want to talk to us about any problems, call JBL Customer Service at  
1-800-336-4JBL Between 9AM and 5PM Eastern time.  
28  
 
Specifications  
Continuous Power Output  
(20Hz – 20kHz,  
14.4V Battery Voltage)  
35 watts x 2  
(4 Ohms, 0.05% THD)  
50 watts x 2  
(2 Ohms, 0.08% THD)  
100 Watts x 1  
(4 Ohms, 0.08% THD)  
Signal to Noise Ratio  
Frequency Response  
100dBA  
10Hz – 50kHz (+0, – 1dB)  
20Hz – 20kHz (+0, – 0.1dB)  
Damping Factor  
Slew Factor  
>200  
>5  
Line Level Input Sensitivity  
(for rated power)  
100mV – 4V RMS (500mV at center detent)  
Line Level Input Impedance  
Speaker Level Input Impedance  
Speaker Level Input Sensitivity  
Preamp Output Sensitivity  
10k Ohms  
15 Ohms  
200mV – 8V RMS (1V at center detent)  
2V Out for 4V Speaker Level Input  
Minimum Speaker Impedance  
Single Ended, Non-Bridged  
Bridged  
2 Ohms  
4 Ohms  
Built-In Electronic Crossover  
Frequency and Slope  
80Hz, 18dB per octave Low Pass Filter  
100Hz, 18dB per octave High Pass Filter  
Power Requirement  
Fuse Size  
11 to 16V DC Negative Ground  
20 Amp ATC Type Fuse  
Size (L x W x H)  
65/8" x 91/4" x 2"  
(168.3mm x 235.0mm x 50.8mm)  
Weight  
4lbs. 3oz. (1.90kg)  
Speaker Input / Output Mating  
Connector  
Molex Mini-Fit Jr. # 39-01-2040  
Metal Pins: 39-00-0038  
Power Mating Connector  
Plastic Housing: AMP #1-480700-0  
Metal Pins for Ground & +12V: AMP # 350923-3  
Metal Pins for Rem. In: AMP # 350536-1  
29  
 
JBL Consumer Products, Inc.  
80 Crossways Park West  
Woodbury, NY 11797  
8500 Balboa Blvd.  
Northridge, CA 91329  
800 336 4JBL  
A Harman International Company  
Part No. JBLGTS100OM  
 

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