JBL GTO 301.1 (serv.man2) Service Manual ▷ View online
CONNECTIONS
–
GTO301.1/GTO301.1II
The GTO subwoofer amplifiers are
single-channel amplifiers. There are
two sets of terminals to make it easy
to connect multiple woofers. Either
set of (+/–) terminals may be used
when connecting woofers.
single-channel amplifiers. There are
two sets of terminals to make it easy
to connect multiple woofers. Either
set of (+/–) terminals may be used
when connecting woofers.
To the right are two application
diagrams to help plan your subwoofer
system installation. Figures 2 and 3
show how to configure the GTO
subwoofer amplifiers
diagrams to help plan your subwoofer
system installation. Figures 2 and 3
show how to configure the GTO
subwoofer amplifiers
NOTE: For simplicity, Figures 2 and 3
do not show power, remote and input
connections.
do not show power, remote and input
connections.
NOTE: Minimum speaker load is
2 ohms.
2 ohms.
3
GTO Amplifier
(partial end panel)
Subwoofer
–
+
GTO Amplifier
(partial end panel)
Subwoofer
Subwoofer
+
–
–
+
Figure 2. GTO subwoofer amplifier with two woofer connections.
Figure 3. GTO subwoofer amplifier with one woofer connection.
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INSTALLATION AND SETUP
SETTING THE
CROSSOVER(S)
Determine your system plans and set the
crossover mode switch accordingly.
CROSSOVER(S)
Determine your system plans and set the
crossover mode switch accordingly.
Initially set the crossover frequency
control midway. While listening to music,
adjust the crossover for the least
perceived distortion from the speakers,
allowing them to reproduce as much
bass as possible.
control midway. While listening to music,
adjust the crossover for the least
perceived distortion from the speakers,
allowing them to reproduce as much
bass as possible.
Systems using a separate subwoofer set
the crossover mode to HP (high pass) for
your full-range speakers. Adjust the
crossover frequency to limit bass and
provide increased system volume with
less distortion.
the crossover mode to HP (high pass) for
your full-range speakers. Adjust the
crossover frequency to limit bass and
provide increased system volume with
less distortion.
For subwoofers, choose the highest
frequency that removes vocal information
from the sound of the subwoofer.
frequency that removes vocal information
from the sound of the subwoofer.
SETTING INPUT
SENSITIVITY
1. Initially turn the INPUT LEVEL control(s)
SENSITIVITY
1. Initially turn the INPUT LEVEL control(s)
to minimum (counter clockwise).
2. Reconnect the (–) negative lead to the
vehicle’s battery. Apply power to the
audio system and play a dynamic music
track.
audio system and play a dynamic music
track.
3. On the source unit, increase the volume
control to 3/4 volume. Slowly increase
the INPUT LEVEL control(s) toward three
o’clock until you hear slight distortion
in the music. Then reduce the INPUT
LEVEL slightly until distortion is no
longer heard.
the INPUT LEVEL control(s) toward three
o’clock until you hear slight distortion
in the music. Then reduce the INPUT
LEVEL slightly until distortion is no
longer heard.
NOTE: After the source unit is on, red LEDs
(on the top panel) will light, indicating the
amplifier is on. If not, check the wiring,
especially the remote connection from the
source unit. Also refer to “Troubleshooting”
on the next page.
(on the top panel) will light, indicating the
amplifier is on. If not, check the wiring,
especially the remote connection from the
source unit. Also refer to “Troubleshooting”
on the next page.
REMOTE LEVEL CONTROL
All three GTO subwoofer
amplifiers have inputs for an optional
remote level control (RLC). This will allow
the amplifier’s input level to be adjusted
from the listening position. Connect the
optional remote level control using the
RJ-11 jack on the side of the amplifier.
Install the control module in the front of
the vehicle within easy reach of the driver.
Under the dash or in the center console
are both suitable locations.
All three GTO subwoofer
amplifiers have inputs for an optional
remote level control (RLC). This will allow
the amplifier’s input level to be adjusted
from the listening position. Connect the
optional remote level control using the
RJ-11 jack on the side of the amplifier.
Install the control module in the front of
the vehicle within easy reach of the driver.
Under the dash or in the center console
are both suitable locations.
SETTING THE BASS BOOST
All three GTO subwoofer amplifiers
are all equipped with a bass-
boost control. This allows you to adjust the
bass output of your system at 50Hz up to
12dB and enhance low frequency.
All three GTO subwoofer amplifiers
are all equipped with a bass-
boost control. This allows you to adjust the
bass output of your system at 50Hz up to
12dB and enhance low frequency.
AUX OUTPUT
All three GTO subwoofer amplifiers are
equipped with full-range outputs that can
be used to connect additional amplifiers.
All three GTO subwoofer amplifiers are
equipped with full-range outputs that can
be used to connect additional amplifiers.
NOTE: When using the high-level inputs,
the AUX outputs can be used to pass a
line-level signal to another amplifier.
the AUX outputs can be used to pass a
line-level signal to another amplifier.
INSTALLING NEON TUBES
(OPTIONAL)
1. Using a Phillips screwdriver, remove all
(OPTIONAL)
1. Using a Phillips screwdriver, remove all
screws on the amplifier’s output/power
end panel and set them aside.
end panel and set them aside.
2. Using a 3 ⁄32-inch Allen wrench, remove
only the screws on the amplifier’s (top)
clear cover and set them aside.
clear cover and set them aside.
3. Remove the end panel and slide the
cover off. Set both parts aside.
4. Locate the enclosed hardware bag and
remove the four clips. Each clip has a
square end and a larger round end.
Using a round end, press two clips onto
each neon tube (e.g., Street Glow AN9
or equivalent), as shown in
square end and a larger round end.
Using a round end, press two clips onto
each neon tube (e.g., Street Glow AN9
or equivalent), as shown in
Figure 13.
5. For each tube, align both clips so the
square ends slide onto an exposed
extrusion edge, as shown in Figure 9.
Do not cover any screw holes. When
installed correctly, each neon tube will
sit under an extrusion and not be visible
when viewed from directly above.
extrusion edge, as shown in Figure 9.
Do not cover any screw holes. When
installed correctly, each neon tube will
sit under an extrusion and not be visible
when viewed from directly above.
6. Route each neon tube’s power cable
through its respective NEON hole on the
end panel (see
end panel (see
Figure 13).
7. Slide the cover back into place and re-
install its screws. Then, replace the end
panel and reinstall its screws.
panel and reinstall its screws.
8. Finish the installation of the neon tubes
as instructed in their owner’s manual.
Figure 12.
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INSTALLATION AND SETUP
To Neon
Power
Supply
To Neon
Power
Supply
Figure 13. Installing neon tubes in a JBL GTO amplifier.
TROUBLESHOOTING
SYMPTOM
LIKELY CAUSE
SOLUTION
No audio
No voltage at BATT+
Check voltages at
(POWER LED
or REM terminals,
amplifier terminals
is off)
or bad or no ground
with VOM
connection
No audio
DC voltage on
Amplifier may need
(PROTECT LED
amplifier output
service; see enclosed
flashes every
warranty card for
4 seconds)
service information
No audio
Amplifier is
Make sure amplifier
(PROTECT
overheated
cooling is not blocked
LED is on)
at mounting location;
verify speaker system
impedance is within
specified limits (see
“Specifications” on
the next page)
verify speaker system
impedance is within
specified limits (see
“Specifications” on
the next page)
No audio
Voltage less than 9V on
Check vehicle
(PROTECT
BATT+ connection
charging system for
and POWER
defective voltage
LEDs flash)
regulator
SYMPTOM
LIKELY CAUSE
SOLUTION
No audio
Voltage more than 16V
Check vehicle
(PROTECT
or less than 8.5V on
charging system for
LED is on)
BATT+ connection
defective voltage
regulator
Distorted audio
Input sensitivity is
Check INPUT
not set properly, or
LEVEL setting; or
amplifier or source
check speaker wires
unit is defective
for shorts or grounds
Distorted audio
Short circuit in
Remove speaker leads
and PROTECT
speaker or wire
one at a time to locate
LED flashes
shorted speaker or
wire, then repair
wire, then repair
Music lacks
Speakers are not
Check speaker
“punch”
connected properly
connections for
proper polarity
proper polarity
GTO Amp OM 2/3/04 3:54 PM Page 7
GTO 301.1/301.1II
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Grand Touring
Grand Touring
GTO 301.1/301.1II
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