Jbl LC-A304, LCA 502, LC-A504, LC-A752 User Manual

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Amplifiers
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Thank you for purchasing a
JBL Loud + Clear amplifier. In order that we may better serve you should you require warranty ser­vice on your new amplifier, please retain your original purchase receipt and return the enclosed warranty registration card.
Important: Installation of auto­motive stereo components can require extensive experience in performing a variety of mechani­cal and electrical procedures. Although these instructions explain, in a general sense, how to install Loud + Clear amplifiers, they may not show the exact installation methods for your particular vehicle. If you feel you lack the tools or necessary experience, ask your authorized JBL car-audio dealer about profes­sional installation options.
Installation Warnings and Tips
• Always wear protective eyewear when using tools.
• Turn off all audio systems and other electrical devices before you start.
• Disconnect the negative (–) lead from your vehicle’s battery.
• Check clearances on both sides of a planned mounting surface before drilling any holes or installing any screws. Remember that the screws can extend behind the surface.
• At the installation sites, locate and make a note of all fuel lines, hydraulic brake lines, vacuum lines and electrical wiring. Use extreme caution when cutting or drilling in and around these areas.
• Before drilling or cutting holes, use a utility knife to remove unwanted fabric or vinyl to keep material from snagging in a drill bit.
• When routing cables, keep input­signal cables away from power cables and speaker wires.
• When making connections, ensure that they are secure and properly insulated.
• If the amplifier’s fuse must be replaced, use only the same type and rating as that of the original. Do not substitute another kind.
Warning: Playing loud music in an automobile can permanently damage your hearing as well as hinder your ability to hear traffic. We recommend listening at low levels while in your car. JBL accepts no liability for hearing loss, bodily injury or property damage resulting from use or misuse of this product.
Choosing a Location and Mounting the Amplifier
Amplifiers need air to stay cool. Suitable locations are under seats (provided the amplifier doesn’t interfere with the seat-adjustment mechanism), in the trunk or in any location that provides enough air for the amp to cool itself. Do not mount the amplifier with the heat-sink fins facing downward; this makes convection cooling of the amplifier impossible.
Mount the amplifier so that it is not damaged by the feet of back-seat passengers or shifting cargo in the trunk. Mount the amplifier so that it remains dry – never mount an amplifier outside the car or in the engine compartment.
Using the amplifier as a template, mark the location of the mounting holes on the mounting surface, drill pilot holes and attach the amplifier to the mounting surface with screws. Make sure the amplifier is mounted securely.
Wiring the Power Connections
Refer to Figures 1–4 for connector locations. Use at least 10-gauge wire for power and ground connections.
For power, remote and ground connections strip off one end of each jacket to reveal bare wire for insertion into the barrier-strip connectors. Connect a wire from the GND connector on the amplifier to the nearest bare-metal chassis component; scrape away the paint to ensure good conductivity. Next, connect a wire between the BATT terminal on the amplifier and the POS ( wire through a factory-installed grommet in the firewall, or install a grommet if a factory grommet is not available. You must install, within 18" of the battery connection, a fuse holder and fuse with the same rating as the fuse in the amplifier’s chassis. This will prevent a short circuit from causing damage to the amplifier or the car. Connect a wire between the REM terminal of the amplifier and the “remote out” or power-antenna lead on the vehicle’s radio.
+) terminal of the vehicle’s battery. Pass the
If you are bridging the amplifier, connect the speaker wires to the termi­nals marked “bridged,” observing proper polarity. The total impedance of the speaker system connected to the amplifier must be at least four ohms in bridged mode.
If you are running the amp in Tri-Mode (stereo and mono simultaneously), connect the satellite speakers to the speaker connector as you would a pair of stereo speakers. Connect the subwoofer to the terminals marked “bridged.” Refer to the chart below to determine the capacitor and inductor values you’ll need to route bass signals to the woofer, and the midrange and high frequencies to the satellite speakers. These passive crossover components will also ensure that the impedance of the speaker system doesn’t drop below two ohms.
FREQUENCY INDUCTOR CAPACITOR
Crossover 6dB/oct. LP 6dB/oct. HP
(4 ohm) (4 ohm)
75Hz 8.0mH 530µF 100Hz 6.4mH 400µF 125Hz 5.0mH 318µF 150Hz 4.2mH 265µF 175Hz 3.6mH 227µF 200Hz 3.2mH 198µF
Wiring the Speaker-Output Connections
Connect the speakers, observing proper polarity, to the speaker-output barrier strip. The total impedance of the speaker system connected to the amplifier when the amplifier is driven in stereo must be at least two ohms.
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Amplifiers
Figure 3
Figure 1
Model No. LC-A502
Model No. LC-A752
Model No. LC-A304
Model No. LC-A504
Figure 4
Figure 2
REM
BATT
(+)
FUSE
20 AMP
GND
(-)
POWER
POWER
FRONT PANEL
REAR PANEL
FRONT PANEL
REAR PANEL
FRONT PANEL
REAR PANEL
FRONT PANEL
REAR PANEL
OUTPUT
LINE INPUT
INPUT LEVEL
LEFT
LEFT
BRIDGED
RIGHT
RIGHT
4V 250mV
REM
BATT
(+)
FUSE
20 AMP
GND
(-)
POWER
POWER
REAR
OUTPUT
LINE INPUT
FRONT
REAR
LINE INPUT
INPUT LEVEL
INPUT LEVEL
LEFT
LEFT
LEFT
BRIDGED
RIGHT
FRONT OUTPUT
LEFT
BRIDGED
RIGHT
RIGHT RIGHT
4V 250mV 4V 250mV
REM
BATT
(+)
FUSE
20 AMP
FUSE
20 AMP
GND
(-)
POWER
REAR
OUTPUT
LEFT
BRIDGED
RIGHT
FRONT OUTPUT
LEFT
LEFTLEFT
BRIDGED
RIGHT
RIGHTRIGHT
LINE INPUT LINE INPUTCROSS
OVER
CROSS
OVER
FRONT REAR
INPUT LEVEL
4V 250mV 4V 250mV
INPUT LEVEL
POWER
LPF
HPF
FLAT
LPF
HPF
FLAT
32Hz 320Hz FREQUENCY
32Hz 320Hz FREQUENCY
LEFT
RIGHT
LINE INPUT CROSS
OVER
INPUT LEVEL
4V 250mV
POWER
LPF
HPF
FLAT
32Hz 320Hz FREQUENCY
REM
BATT
(+)
FUSE
25 AMP
GND
(-)
POWER
OUTPUT
LEFT
BRIDGED
RIGHT
Wiring the Input-Signal Connections
Connect a pair of signal cables with RCA-type ends between the connectors on the amplifier and the RCA-type signal connectors on the source unit. If your radio has only speaker-level outputs, you must purchase a speaker­level-to-line-level adapter, commonly sold as an accessory.
System Setup and Adjustment
Refer to figures 1–4 for location of adjustment switches and controls.
Electronic Crossover (for LC-A752 and LC-A504)
The electronic crossover can be selected as a 12dB/oct high-pass filter (HPF), 12dB/oct low-pass filter (LPF) or it can be defeated (FLAT). The crossover frequency can be set at any frequency between 32Hz and 320Hz.
Setting Input Level
Initially, turn the input-sensitivity LEVEL control to its maximum (counterclockwise) position. Turn on the source unit and increase the volume control until it is approximately three-quarters of maximum­output level. Slowly increase the input LEVEL control (clockwise) while listening to the quality of the reproduced sound. When you hear distor­tion on the music peaks, turn the LEVEL control back slightly. This is the maximum undistorted output level of your system. Turning the LEVEL control up farther WILL NOT INCREASE THE OUTPUT POWER OF YOUR AMP! It will only decrease the amount of volume control rotation before the amp is at full output power. It will also increase the amount of extraneous noise present in your system.
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Amplifiers
Troubleshooting
Symptom Likely Cause Solution
No audio (power indicator is on). Speakers or input-signal cables disconnected; Check connections, source, speakers.
No audio (power indicator is off). No voltage at BATT or REM terminals; Check voltage at amplifier terminals
No audio (power indicator is off, Amplifier protection is engaged due to Disconnect speaker leads one at voltage at terminal OK). overheating; shorted or defective speaker a time to determine which speaker
Distorted audio. Input sensitivity not set properly; amplifier Check LEVEL setting; check source
Music lacks "punch". Speakers are not connected properly. Check speaker connections
defective speaker or source unit.
bad ground connection. with VOM. Repair faulty connection.
or speaker cable. or wire is shorted or defective.
or source unit defective. unit.
LC-A502
LC-A752
Repair the short circuit or replace bad speaker.
for proper polarity.
LC-A304
LC-A504
Specifications
Power Output, 4 Ohms 50W x 2
Power Output, 2 Ohms 65 W x 2
Power Output, 4 Ohms Bridged 130W x 1
Frequency Response 20Hz – 40kHz
Input Sensitivity 250mV – 4V
THD + Noise .10%
Signal-to-Noise Ratio
Maximum Current Draw 20A
Dimensions (H x W x D) 2-5/16" x 8-5/16" x 7-9/16"
(58mm x 217mm x 191mm)
>90dB
75W x 2
90W x 2
180W x 1
20Hz – 40kHz
250mV – 4V
.10%
>90dB
26A
2-5/16" x 8-5/16" x 12-1/2"
(58mm x 217mm x 317mm)
2-5/16" x 8-5/16" x 11-5/8"
(58mm x 217mm x 297mm)
30W x 4
37.5W x 4
75W x 2
20Hz – 40kHz
250mV – 4V
.10%
>90dB
23A
62.5W x 4
20Hz – 40kHz
250mV – 4V
2-5/16" x 8-5/16" x 14-1/16"
(58mm x 217mm x 357mm)
50W x 4
125W x 2
.10%
>90dB
42A
JBL Consumer Products 250 Crossways Park Drive, Woodbury, NY 11797 8500 Balboa Boulevard, Northridge, CA 91329 1-800-336-4JBL (4525) (USA only) www.jbl.com
1999 JBL, Incorporated
©
JBL is a registered trademark of JBL, Incorporated.
Part No. LC-AMPOM 3/99
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