JL Audio Car Stereo System 300 2 User Manual

JL AUDIO 300/2  
two-channel full-range amplifier  
o w n e r ’ s m a n u a l  
Thank you for purchasing a JL Audio amplifier for  
your automotive sound system.  
Your amplifier has been designed and manufactured to exacting  
standards in order to ensure years of musical enjoyment in your  
vehicle. For maximum performance and extended warranty  
coverage, we highly recommend that you have your new amplifier  
installed by an authorized JL Audio dealer. Your authorized  
dealer has the training, expertise and installation equipment to  
ensure optimum performance from this product. Should you  
decide to install the amplifier yourself, please take the time  
to read this manual thoroughly so as to familiarize yourself  
with its installation requirements and setup procedures.  
If you have any questions regarding the instructions in this  
manual or any aspect of your amplifier’s operation, please contact  
your authorized JL Audio dealer for assistance. If you need further  
assistance, please call the JL Audio Technical Support Department at  
(954) 443-1100 during business hours (Eastern Time Zone).  
 
PRODUCT DESCRIPTION  
POWER CONNECTIONS  
The JL Audio 300/2 is a two-channel full-range  
amplifier utilizing patented Absolute Symmetry™  
Class AB technology for both channels.These  
channels benefit from JL Audio's exclusive R.I.P.S.  
power supply design which optimizes the output of  
for any impedance between 1.5 and 4 ohms per  
channel (3 - 8bridged).  
The 300/2's flexible input and crossover sections  
permit operation with a wide variety of source units  
and system configurations.  
6) Find a good, solid metal grounding point  
close to the amplifier and connect the negative  
power wire to it using appropriate hardware. Use  
minimum 8 AWG power wire, no longer than 36  
inches (90 cm) from the amplifier to the ground  
connection point. In some vehicles, it may be  
necessary to upgrade the battery ground wire.  
(See page 5 for important notice).  
7) Securely mount the amplifier using the  
supplied screws.  
8) Connect the positive and negative power  
wires to the amplifier.A fuse near the amplifier is  
not necessary.  
9) Connect the remote turn-on wire  
to the amplifier.  
Before installing the amplifier, disconnect the  
negative (ground) wire from the vehicle's battery.  
This will prevent accidental damage to the system,  
the vehicle and your body during installation.  
The ground connection should be made using  
the same gauge wire as the power connection  
and should be kept as short as possible, while  
accessing a solid piece of sheet metal in the vehicle.  
The surface of the sheet metal should be sanded at  
the contact point to create a clean, metal-to-metal  
connection between the chassis and the termination  
of the ground wire.The use of a star washer to lock  
down the connection is advisable.  
Any wires run through metal barriers (such as  
firewalls), must be protected with a high quality  
rubber grommet to prevent damage to the  
insulation of the wire. Failure to do so may result in  
a dangerous short circuit.  
TYPICAL INSTALLATION SEQUENCE  
The following represents the sequence for a  
typical amplifier installation, using an aftermarket  
source unit. Additional steps and different  
procedures may be required in some applications. If  
you have any questions, please contact your  
authorized JLAudio dealer for assistance.  
The 300/2's “+12VDC” and “Ground”  
connections are designed to accept 8 - 4 AWG  
power wire. 8 AWG is the minimum  
recommended power wire size for this  
amplifier.  
IMPORTANT  
!
10) Connect the RCA input cables  
to the amplifier.  
Many vehicles employ small (10 AWG - 6 AWG)  
wire to ground the battery to the vehicle chassis and  
to connect the alternator's positive connection to the  
battery.To prevent voltage drops, these wires should  
be upgraded to 4 AWG when installing amplifier  
systems with main fuse ratings above 60A.  
11) Connect the speaker wires to the amplifier.  
12) Carefully review the amplifier’s control  
settings to make sure that they are set according to  
the needs of the system.  
13) Install power wire fuse (40A for a  
single 300/2) and reconnect the negative  
battery post terminal.  
14) Turn on the source unit at a low level  
to double-check that the amplifier is configured  
correctly. Resist the temptation to crank it up until  
you have verified the control settings.  
15) Make necessary adjustments to the input  
sensitivity controls to obtain the right overall output  
and the desired balance in the system. See  
Appendix B (page 13) for the recommended input  
sensitivity setting method.  
If you are installing the 300/2 with other  
1) Disconnect the negative battery post  
connection and secure the disconnected cable to  
prevent accidental re-connection during installation.  
This step is not optional!  
2) Run power wire (minimum 8 AWG) from  
the battery location to the amplifier mounting  
location, taking care to route it in such a way that  
it will not be damaged and will not interfere with  
vehicle operation. Use 2 AWG or 1/0 AWG  
power wire if additional amplifiers are being  
installed with the 300/2.  
3) Connect power wire to the positive battery  
post. Fuse the wire with an appropriate fuse block  
(and connectors) within 18 inches (45 cm) wire  
length of the positive battery post. This fuse is  
essential to protect the vehicle. Do not install the  
fuse until the power wire has been connected to  
the amplifier.  
4) Run signal cables (RCA cables) and remote  
turn-on wire from the source unit to the amplifier  
mounting location.  
amplifiers and wish to use a single main power wire,  
use 2 AWG or 1/0 AWG main power wire  
(depending on the overall current demands of all  
the amplifiers in the system).This 2 AWG or 1/0  
AWG power wire should terminate into a  
distribution block mounted as close to the amplifiers  
as possible and should connect to the 300/2 with  
8 - 4 AWGpower wire.  
Please note that smaller AWG numbers mean  
bigger wire and vice-versa (1/0 AWG is biggest, 2  
AWG is smaller, then 4 AWG, then 8 AWG, etc.).  
To connect the power wires to the amplifier, first  
back out the set screw on the top of the amplifier,  
using the supplied 2.5 mm hex wrench. Strip  
1/2 inch (12 mm) of insulation from the end of  
each wire and insert the bare wire into the  
receptacle on the front panel of the amplifier, seating  
it firmly so that no bare wire is exposed.While  
holding the wire in place, tighten the set screw  
firmly, taking care not to strip the head of the screw.  
16) Enjoy the fruits of your labor with your  
favorite music.  
5) Run speaker wire from the speaker systems to  
the amplifier mounting location.  
4
JL AUDIO 300/2  
JL AUDIO 300/2  
5
 
FUSE REQUIREMENTS  
TURN-ON LEAD  
INPUT SECTION  
It is absolutely vital that the main power wire(s)  
to the amplifier(s) in the system be fused within  
18 inches (45 cm) of the positive battery post  
connection.The fuse value at each power wire  
should be high enough for all of the equipment  
being run from that power wire. If only the  
300/2 is being run from that power wire, we  
recommend a 40A fuse be used. AGU (big glass  
fuse) or MaxiFuse™ (big plastic-body fuse) types  
are recommended.  
The 300/2 uses a conventional +12V remote  
turn-on lead, typically controlled by the source unit's  
remote turn-on output.The amplifier will turn on  
when +12V is present at its “Remote” input and  
turn off when +12V is switched off. If a source unit  
does not have a dedicated remote turn-on output,  
the amplifier’s turn-on lead can be connected to  
+12V via a switch that derives power from an  
ignition-switched circuit.  
The 300/2's “Remote” turn-on connector is  
designed to accept 18 AWG – 8 AWG wire.  
12 AWG is more than adequate for this purpose.  
To connect the remote turn-on wire to the  
amplifier, first back out the set screw on the top of  
the amplifier, using the supplied hex wrench. Strip  
1/2 inch (12mm) of wire and insert the bare wire  
into the receptacle on the front panel of the  
amplifier, seating it firmly so that no bare wire is  
exposed.When using smaller wire, it may be  
necessary to strip 1 inch of insulation from the wire  
and fold the bare wire in half prior to insertion.  
While holding the wire in the terminal, tighten the  
set screw firmly, taking care not to strip the head of  
the screw and making sure that the wire is firmly  
gripped by the set screw.  
The 300/2 has one input section, which contains a  
pair of RCA-type input jacks, an “InputVoltage”  
switch and an “Input Sens.rotary control.  
2) Input Sensitivity Adjustment: Located next to  
the “InputVoltage” switch in the “Amplifier Input  
Section” nput section is a rotary control labeled  
“Input Sens.. Once the appropriate “Input  
Voltage” range has been selected, this control can  
be used to match the source unit's output voltage  
to the input stage of the 300/2 for maximum clean  
output. Rotating the control clockwise will result in  
higher sensitivity (louder for a given input voltage).  
Rotating the control counter-clockwise will result in  
lower sensitivity (quieter for a given input voltage.)  
To properly set the amplifier for maximum clean  
output, please refer to Appendix B (page 13) in this  
manual. After using this procedure, you can then  
adjust the “Input Sens.level downward if this is  
required to achieve the desired system balance.  
Do not increase the “Input Sens.setting for  
any amplifier in the system beyond the maximum  
level established during the procedure outlined in  
Appendix B (page 13). Doing so will result in  
audible distortion and possible speaker damage.  
No fuse is required or recommended directly  
before the amplifier power connection. If one is  
desired, we recommend the use of a 40A AGU fuse  
or MaxiFuse™ type.  
1) InputVoltage Range: A wide range of signal  
input voltages can be accommodated by the  
300/2's input section (200mV – 8V).This wide  
range is split up into two sub-ranges, accessible via  
a switch located in the “Amplifier Input Section”.  
The “Low” position on the “InputVoltage”  
switch selects an input sensitivity range between  
200mV and 2V.This means that the “Input Sens.”  
rotary control will operate within that voltage  
window. If you are using an aftermarket source unit,  
with conventional preamp-level outputs, this is most  
likely the position that you will use.  
The “High” position on the “InputVoltage”  
switch selects an input sensitivity range between  
800mV and 8V.This is useful for certain high-output  
preamp level signals as well as speaker-level output  
from source units and small amplifiers.To use  
speaker-level sources, splice the speaker output  
wires of the source unit or small amplifier onto a  
pair of RCA plugs.  
IMPORTANT  
!
The output of the amplifier will decrease for a  
given input voltage when the “Input Range” switch  
is placed in the “High” position. Conversely, the  
output will be higher with the switch in the “Low”  
position.While this may sound counter-intuitive, it is  
consistent with the descriptions above.  
6
JL AUDIO 300/2  
JL AUDIO 300/2  
7
 
CROSSOVER CONTROLS  
PREAMP OUTPUT SECTION  
SPEAKER OUTPUTS  
Crossovers are groups of individual electronic filters  
which allow only certain frequency ranges to pass  
through them by attenuating frequencies outside  
the selected range.These filters allow the user to  
specify what frequency range will be sent to the  
each amplifier (or channels) in a system.This, in turn,  
allows each speaker system to only reproduce a  
range of frequencies it is well-suited for, resulting in  
reduced distortion and improved fidelity.  
2) “Filter Slope” Control: This switch allows  
you to select from two filter slopes for that  
channel section.  
“12dB”: Configures the filter to attenuate  
frequencies above or below the selected filter  
frequency at a rate of 12 dB per octave  
(Butterworth alignment).  
“24dB”: Configures the filter to attenuate  
frequencies above or below the selected filter  
frequency at a rate of 24 dB per octave (Linkwitz-  
Riley alignment).  
The 300/2 incorporates a flexible preamp output  
section, so that additional amplifiers can be added to  
the system.This pre-amp output can be configured  
three different ways using the switch labeled  
“Output Mode” in the “Preamp Output Section”.  
The 300/2 employs JL AUDIO's exclusive  
Regulated, Intelligent Power Supply (R.I.P.S.) design.  
This sophisticated power supply allows the  
amplifier to produce its optimum power (300  
watts) over a wide range of speaker impedances.  
Unlike conventional amplifiers that require a  
specific impedance to produce optimum power,  
the R.I.P.S.-equipped 300/2 gives you the freedom  
to use a variety of speaker configurations that  
achieve final impedances between 1.5 – 4Ω  
nominal per channel (without sacrificing power  
output or sound quality).  
Amp Filter Section:  
Depending on the speaker system and the  
vehicle, different filter slopes may be required to  
produce a smooth transition between the sound of  
different speakers in the system. Experiment to find  
the slope which best matches the acoustic  
requirements of the system.The sharper “24dB”  
setting will do a better job of protecting small  
speakers with limited power handling.The shallower  
“12dB” octave setting allows the rear speakers to  
reproduce more low-frequency content.  
3) “Freq. Range” Control: When thrown to  
the right, this switch multiplies the cutoff  
frequency selected by the rotary “Filter Freq.  
(Hz)” control by a factor of 10. In the “x1”  
position, the range of the rotary control is  
50 - 500 Hz (as marked). In the “x10”  
position, the range of the rotary control is  
500 Hz - 5 kHz (5000 Hz).  
The operation of the R.I.P.S. circuitry is entirely  
automatic and adjusts itself every time the amplifier  
is turned on according to the lowest impedance  
present at the speaker outputs .There are no user  
controls to configure.The system operates through  
multiple stages of impedance optimization, choosing  
the stage most appropriate to the actual impedance  
of the speakers you connect to it.  
1) “Full-Range”: The preamp output delivers  
the same signal that is connected to the 300/2's  
Amplifier Inputs.  
2) “Low-Pass”: The preamp output delivers  
the same signal that is connected to the 300/2's  
Amplifier Inputs with Low-Pass filtering applied to  
it at the “Filter Freq.and “Filter Slope” selected  
in the “Amplifier Filter” section. This mode can  
be useful for feeding a subwoofer amplifier  
when the 300/2 is being used to drive the  
main speaker system.  
3) “High-Pass”:The preamp output delivers  
the same signal that is connected to the 300/2's  
Amplifier Inputs with High-Pass filtering applied to  
it at the “Filter Freq.and “Filter Slope” selected  
in the “Amplifier Filter” section. This mode can  
be useful for feeding a second satellite amplifier  
when the 300/2 is being used to drive the main  
speaker system.  
1) “Filter Mode” Control:This switch allows you to  
configure the filter into one of two filter types or  
defeat it completely:  
“Off”: Defeats the filter for that channel section  
completely, allowing the full range of frequencies  
present at the inputs to feed the amplifier.This is  
useful for systems utilizing outboard crossovers or  
requiring full-range reproduction from the 300/2.  
“LP” (Low-Pass): Configures the filter to attenuate  
frequencies above the selected filter frequency.  
Useful for connection of subwoofer(s) to the 300/2.  
“HP” (High-Pass): Configures the filter to attenuate  
frequencies below the selected filter frequency.  
Useful for connection of component speakers to  
the 300/2 in a bi-amplified system.  
4) “Filter Freq. (Hz)The filter frequency  
markings surrounding this rotary control are for  
reference purposes and are generally accurate to  
within 1/3 octave or better. If you would like to  
select the filter cutoff frequency with a higher level  
of precision, consult the chart in Appendix A  
(page 12) of this manual.  
IMPORTANT  
!
If you connect a load higher than 4nominal  
per channel in stereo mode (or 8in bridged  
mode), power will drop by half with every  
doubling of impedance above 4stereo / 8Ω  
mono. If you connect a load lower than 1.5Ω  
nominal per channel in stereo mode (or 3in  
bridged mode, the amplifier protection circuitry  
activates a “safe” mode which reduces amplifier  
power to protect the circuitry from failure (the  
yellow “Low LED lights to indicate that this  
has happened). See page 10 for details.  
NOTE: The signal level of the “Preamp Output” is  
affected by the setting of the “InputVoltage Range”  
switch of the amplifier. See the “InputVoltage  
Range” section (page 7) for details on “Input  
Voltage” settings.The preamp output level is not  
affected by the “Input Sens.rotary control.  
IMPORTANT  
!
Speaker loads below 1.5nominal per channel  
in stereo or 3nominal in bridged mode are not  
recommended and may cause the amplifier output  
to distort excessively.  
8
JL AUDIO 300/2  
JL AUDIO 300/2  
9
 
BRIDGING CONSIDERATIONS  
STATUS INDICATOR LIGHTS /  
PROTECTION CIRCUITRY  
SERVICINGYOUR JL AUDIO AMPLIFIER  
If your amplifier fails or malfunctions, please  
return it to your authorized JL Audio dealer so  
that it may be sent in to JL Audio for service.  
There are no user serviceable parts or fuses  
inside the amplifier.The unique nature of the  
circuitry in the JL Audio amplifiers requires  
specifically trained service personnel. Do not  
attempt to service the amplifier yourself or  
through unauthorized repair facilities.This will not  
only void the warranty, but may result in the  
creation of more problems within the amplifier.  
Bridging is the practice of combining the output  
of two amplifier channels to drive a single load.  
When bridged, each channel produces signals of  
equal magnitude, but opposite polarity.The  
combined output of the two channels provides  
twice the output voltage available from a single  
channel.The 300/2 has been designed for bridging  
of its channel pairs without the need for input  
inversion adaptors.  
There are three status indicator lights on the top  
of the amplifier. These are as follows:  
1) “Power” (Green): lights to indicate that the  
amplifier is turned on and operating normally.  
2) “Thermal” (Red): lights to indicate that the  
amplifier has exceeded its safe operating  
temperature, putting the amplifier into a self-  
protection mode, which reduces the power  
output of the amplifier. The red light will shut off  
and the amplifier will return to normal, full-power  
operating mode if the heat sink temperature  
drops back to a safe level.  
3) “Low ” (Amber): lights to indicate that the  
impedance of the speaker load connected to the  
amplifier is lower than the optimum load impedance  
range for the amplifier.When this light is on, a  
protection circuit engages and reduces the power  
output of the amplifier.The amber indicator will also  
light when a short-circuit is detected in the speaker  
wiring (this can be a short between the positive and  
negative speaker wires or between either speaker  
wire and the vehicle chassis).This can be used to  
diagnose a short-circuit by only connecting one of  
channel at a time.The amber LED will light when  
you connect the section that is experiencing the  
problem and turn the volume up.  
There is only one condition that will shut  
down an undamaged 300/2 completely…  
If battery voltage drops below 10 volts, the entire  
amplifier will shut itself off.The green “Power”  
indicator on the top of the amplifier will turn off  
when this occurs.The amplifier will turn back on  
when voltage climbs back above 10 volts.This may  
happen in a rapid cycle when bass-heavy program  
material causes a weak charging system to dip  
below 10 volts momentarily. If this is happening in  
your system, have your charging system inspected to  
make sure it is working properly.A 0.5 or 1.0 Farad  
rapid-discharge capacitor connected in parallel to  
the amplifier power connections will minimize these  
short duration voltage dips in most systems that are  
having this problem.  
If you have any questions about the installation or  
setup of the amplifier not covered in  
this manual, please contact your dealer or the  
JL AUDIO Technical Department for assistance:  
(954) 443-1100  
9:00 AM – 5:30 PM Eastern Time,  
Monday – Friday  
To bridge a pair of channels, use the “Left +” and  
“Right –” speaker connectors only (the “Left –”  
and “Right +” remain unused).When bridged, the  
300/2 will deliver optimum power into a 3 - 8Ω  
load. Operating a bridged 300/2 into a load lower  
than 3is not recommended.  
Because a bridged pair of channels requires that  
both channels receive input, you need to connect  
both left and right RCA inputs to the source unit.  
Connection of only one RCA input will result in  
reduced power output, increased distortion and can  
cause the amplifier to overheat. Do not do this!  
Instead, use a “Y-Adaptor” to split the mono signal  
into both left and right RCA inputs.  
Why a mono signal? If you are bridging a pair of  
channels and use a stereo input, the only  
information that will reach the amplifier stage is the  
common-phase portion of the signal.This may be  
useful for passively deriving a center-channel signal,  
but is not going to give you a defined left or right  
channel. If you are looking to reproduce a single  
channel’s signal, you must split the mono signal with  
a “Y-Adaptor” and connect it to both left and right  
RCA inputs for the bridged channel pair.  
For information on troubleshooting this  
amplifier, refer to Appendix C (page 14).  
10  
JL AUDIO 300/2  
JL AUDIO 300/2  
11  
 
APPENDIX A:  
APPENDIX B:  
Precise Frequency Selection Chart  
Input Sensitivity Level Setting  
FILTER FREQAMP FILTER  
JLAudio amplifiers utilizing the Regulated  
6)Verify that you have disconnected the  
speakers before proceeding. Play a track with an  
appropriate sine wave (within the frequency range  
to be amplified by the 300/2) at 3/4 source unit  
volume.  
7) Connect the AC voltmeter to the “Speaker  
Outputs” connectors of the amplifier. If the channel  
pair is operating in stereo, it is only necessary to  
measure one channel. If bridged, make sure you test  
the voltage at the correct connectors (L+ and R–).  
8) Increase the “Input Sens.control until the  
target voltage is observed with the voltmeter. If  
excessive voltage is read with the control at  
minimum (full counterclockwise), switch the “Input  
Voltage” switch to “High” and re-adjust.  
Detent  
Number  
Panel  
Marking  
Actual  
Freq.  
Intelligent Power Supply (R.I.P.S.) allow delivery of  
their rated power when connected to any load  
impedance from 1.5 - 4per channel (3 - 8Ω  
bridged) and when connected to a charging system  
with any voltage from 11 - 14.5V. This design is  
beneficial for many reasons. One of these reasons is  
ease of setup. Because each JLAudio amplifier will  
always deliver the same amount of power within its  
operational range of impedances and supply  
voltages, the maximum, unclipped output is very  
predictable.This makes setting the gain structure via  
the input sensitivity controls very simple. Following  
the directions below will allow the user to adjust  
the input sensitivity of the amplifier(s) simply and  
easily in just a few minutes using equipment which is  
commonly available in installation bays.  
Full counter-clockwise: 58  
01 . . . . . . . . . . . . . . . . . . . . . . . .58  
02 . . . . . . . . .“50” . . . . . . . . .58  
03 . . . . . . . . . . . . . . . . . . . . . . . .58  
04 . . . . . . . . . . . . . . . . . . . . . . . .58  
05 . . . . . . . . . . . . . . . . . . . . . . . .59  
06 . . . . . . . . . . . . . . . . . . . . . . . .60  
07 . . . . . . . . . . . . . . . . . . . . . . . .61  
08 . . . . . . . . .“60” . . . . . . . . .63  
09 . . . . . . . . . . . . . . . . . . . . . . . .65  
10 . . . . . . . . . . . . . . . . . . . . . . . .67  
11 . . . . . . . . . . . . . . . . . . . . . . . .69  
12 . . . . . . . . . . . . . . . . . . . . . . . .71  
13 . . . . . . . . . . . . . . . . . . . . . . . .74  
14 . . . . . . . . .“75” . . . . . . . . .77  
15 . . . . . . . . . . . . . . . . . . . . . . . .80  
16 . . . . . . . . . . . . . . . . . . . . . . . .82  
17 . . . . . . . . . . . . . . . . . . . . . . . .85  
18 . . . . . . . . . . . . . . . . . . . . . . . .90  
19 . . . . . . . . . . . . . . . . . . . . . . . .93  
20 . . . . . . . . .“95” . . . . . . . . .97  
21 . . . . . . . . . . . . . . . . . . . . . . .102  
22 . . . . . . . . . . . . . . . . . . . . . . .107  
23 . . . . . . . . . . . . . . . . . . . . . . .113  
24 . . . . . . . . . . . . . . . . . . . . . . .120  
25 . . . . . . . . . . . . . . . . . . . . . . .127  
26 . . . . . . . . .“130” . . . . . . . .135  
27 . . . . . . . . . . . . . . . . . . . . . . .143  
28 . . . . . . . . . . . . . . . . . . . . . . .153  
29 . . . . . . . . . . . . . . . . . . . . . . .171  
30 . . . . . . . . . . . . . . . . . . . . . . .182  
31 . . . . . . . . . . . . . . . . . . . . . . .201  
32 . . . . . . . . .“200” . . . . . . . .223  
33 . . . . . . . . . . . . . . . . . . . . . . .253  
34 . . . . . . . . . . . . . . . . . . . . . . .289  
35 . . . . . . . . . . . . . . . . . . . . . . .337  
36 . . . . . . . . . . . . . . . . . . . . . . .404  
37 . . . . . . . . . . . . . . . . . . . . . . .474  
38 . . . . . . . . .“500” . . . . . . . .514  
39 . . . . . . . . . . . . . . . . . . . . . . .525  
Full-clockwise: 542  
9) Once you have adjusted the 300/2 to its  
maximum low-distortion output level, reconnect  
the speaker(s).The “Input Sens.controls can now  
be adjusted downward if the amplifier requires  
attenuation to achieve the desired system balance.  
Necessary Equipment  
• Digital ACVoltmeter  
• CD with a sine-wave test tone recorded at 0 dB  
reference level in the frequency range to be  
amplified for that set of channels (50 Hz for  
subwoofer channels, 1 kHz for a midrange  
application). Do not use attenuated test tones  
(-10 dB, -20 dB, etc.).  
IMPORTANT  
!
Do not increase any “Input Sens.setting in  
the system beyond the maximum level established  
during this procedure. Doing so will result in  
audible distortion and possible speaker damage.  
It will be necessary to re-adjust the “Input  
Sens.for the affected channels if any equalizer  
boost is activated after setting the “Input Sens.”  
with this procedure.This applies to any EQ boost  
circuit, including source unit tone controls or EQ  
circuits. EQ cuts will not require re-adjustment.  
The Nine-Step Procedure  
1) Disconnect the speaker(s) from the  
amplifier’s “Speaker Outputs”connectors.  
2)Turn off all processing on the source unit  
(bass/treble, loudness, EQ, etc.). Set fader control to  
center position and subwoofer level control to 3/4  
of maximum (if used to feed the 300/2).  
3) Switch the “InputVoltage” to “Low” and  
turn the “Input Sens.control all the way down.  
4) Set the source unit volume to 3/4 of full  
volume. This will allow for reasonable gain overlap  
with moderate clipping at full volume.  
Nom.  
Target ACVoltage  
Impedance Stereo  
Bridged  
8Ω  
6Ω  
24.5V  
24.5V  
24.5V  
21.2V  
17.3V  
15.0V  
49.0V  
42.4V  
4Ω  
34.6V  
5) Using the chart below, determine the target  
voltage for input sensitivity adjustment according to  
the nominal impedance of the speaker system  
connected to the amplifier outputs.  
3Ω  
30.0V  
2Ω  
not recommended  
not recommended  
1.5Ω  
12  
JL AUDIO 300/2  
JL AUDIO 300/2  
13  
 
APPENDIX C: TROUBLE SHOOTING  
MY AMPLIFIER DOESNTTURN ON”  
MY AMPLIFIERTURNS ON, BUTTHERE IS NO OUTPUT”  
Check the input signal using an AC voltmeter to measure the  
Check to make sure there is +12V at the “Remote” connection of  
the amplifier. In some cases, the turn-on lead from the source  
unit is insufficient to turn on multiple devices and the use of a  
relay is required. To test for this problem, jump the “+12V”  
wire to the “Remote” terminal to see if the amplifier turns on.  
If this does not work, proceed to the next step.  
voltage from the source unit while an appropriate test tone  
is played through the source unit (disconnect the RCA  
cables from the amplifier prior to this test).The frequency  
used should be in the range that is to amplified by the  
amplifier (example: 50 Hz for a sub bass application or  
1 kHz for a full range / high-pass application). A steady  
voltage should be present at the output of the RCA cables.  
If you are receiving a sufficient voltage (between 0.2 and 8.0-  
volts), check to ensure that the speaker wires are making a  
good connection with the metal inside the amplifier. The  
connectors are designed to accept up to an 8 AWG wire. If  
you are using significantly smaller wire (14 AWG or smaller),  
you may have difficulty making an adequate connection. In  
this case, you may find it necessary to “fold” the wire over  
once (or twice!) so as to make a solid connection. Make  
sure to strip the wire to allow for a sufficient connection  
with the input or output of the amplifier.  
Check the fuse, not just visually, but with a continuity meter. It is  
possible for a fuse to have poor internal connections that  
cannot be found by visual inspection. It is best to take the  
fuse out of the holder for testing. If no problem is found  
with the fuse, inspect the fuse-holder.  
I GET A DISTORTED / ATTENUATED SOUND COMING OUT OFTHE SPEAKER(S)”  
Check the speaker wires for a possible short, either between the  
positive and negative or between a speaker lead and the  
vehicle’s chassis ground. If a short is present you will  
experience distorted and/or attenuated output.The  
“Low light may also illuminate in this situation. It may be  
helpful to disconnect the speaker wires from the amplifier  
and use a different set of wires connected to a test speaker.  
Check the nominal load impedance to verify that each channel  
of the amplifier is driving a load between 1.5 - 4Ω  
Check the output of the amplifier. Using the procedure explained in  
the previous check item (after plugging the RCA cables back  
into the amplifier) test for output at the speaker outputs of the  
amplifier. Unless you enjoy test tones at high levels, it is a good  
idea to remove the speaker wires from the amplifier while  
doing this. Turn the volume up approximately half way.  
5 volts or more should be measured at the speaker outputs.  
This output level can vary greatly between amplifiers but it  
should not be in the millivolt range with the source unit at half  
volume. If you are reading sufficient voltage, check your speaker  
connections as explained above.  
(3 - 8bridged).  
Check the input signal and input signal cables to make sure signal is  
present at the “Amplifier Input Section” and the cables are  
not pinched or loose. It may be helpful to try a different set of  
cables and/or a different signal source to be sure.  
MY AMPLIFIER SHUTS OFF ONCE IN AWHILE, USUALLY AT HIGHERVOLUMES”  
Check your voltage source and grounding point.The R.I.P.S. power  
supply is rated to operate with source voltages between  
MY AMPLIFIERS OUTPUT FLUCTUATESWHEN ITAP ON IT OR HIT A BUMP”  
Check the connections to the amplifier. Make sure that the insulation  
for all wires has been stripped back far enough to allow a  
good contact area inside the amplifier terminal.  
11 - 14.5V. Shutdown problems at higher levels can occur  
when the charging system voltage drops below 10 volts.These  
dips can be of very short duration making them extremely  
difficult to detect with a common DC voltmeter.To ensure  
proper voltage, inspect all wiring and termination points. It is  
also a good idea to improve the vehicle’s factory ground wire  
and termination point. Grounding problems are the leading  
cause of mis-diagnosed amplifier failures.  
Check the RCA connectors to ensure that both the center pin and  
the outer shield are making good contact with the input jacks  
on the amplifier.  
HOW DO I PROPERLY SETTHE INPUT SENSITIVITY ON MY AMPLIFIER”  
Please refer to Appendix B (page 13) to set the input sensitivity for  
maximum, low-distortion output.  
14  
JL AUDIO 300/2  
JL AUDIO 300/2  
15  
 
APPENDIX D:  
300/2 Specifications  
GENERAL SPECIFICATIONS:  
Recommended FuseValue: 40A  
Recommended Fuse Type: AGU or MaxiFuse™  
INPUT SECTIONS:  
No. of Inputs: One Stereo Pair  
Input Type: Differential-balanced with RCA jack inputs  
Input Range: Switchable from 200mV - 2V RMS  
to 800mV - 8V RMS  
AMPLIFIER SECTION:  
Amplifier Topology: Class AB with patented Absolute  
Symmetry™ dual N-Channel MOSFET output design  
Power Supply: Independent, pulse width modulation-  
regulated switching power supply with multistage  
impedance optimizing circuitry.  
Rated Power (Stereo):  
150W RMS x 2 @ 1.5-4(11V - 14.5V)  
Rated Power (Bridged):  
300W RMS x 1 @ 3-8(11V - 14.5V)  
THD at Rated Power: <0.03% @ 4per channel  
(20 Hz-20 kHz)  
Signal to Noise Ratio: >108.5 dB referred to rated power  
(A-weighted, 20 Hz-20 kHz noise bandwidth)  
Frequency Response: 5 Hz - 30 kHz (+0, -1dB)  
Damping Factor: >200 @ 4per ch. / 50 Hz, >100 @ 2Ω  
per ch. / 50 Hz  
Slew Rate: 25V/µs  
AMPLIFIER FILTER:  
Filter Type: State-variable, 12 dB/octave Butterworth or 24  
dB/octave Linkwitz-Riley Low-Pass or High-Pass with  
continuously variable cutoff frequency from 50 - 500 Hz,  
switchable to a range of 500 - 5000 Hz, via x10 switch.  
Defeatable.  
PREAMP OUTPUT:  
2-Channel, switch-selectable as pass-through type, tracking  
High-Pass, or tracking Low-Pass linked to Amplifier Filter.  
DIMENSIONS (LxWxH):  
13.4" x 9.25" x 2.36" (340mm x 235mm x 60mm)  
Due to ongoing product development, all specifications are  
subject to change without notice.  
16  
JL AUDIO 300/2  
JL AUDIO 300/2  
17  
 
INSTALLATION NOTES:  
Use this diagram to document your amplifier’s switch and control positions.  
18  
JL AUDIO 300/2  
JL AUDIO 300/2  
19  
 
LIMITEDWARRANTY - AMPLIFIERS (USA)  
JL AUDIO warrants this product to be free of defects in materials and workmanship for a period of ninety  
(90) days from the original date of purchase.The warranty term is extended to two (2) years if installation is  
performed or approved by an authorized JL AUDIO dealer (proof of installation or approval required on  
purchase receipt).  
This warranty is not transferrable and applies only to the original purchaser from an authorized JL AUDIO  
dealer. Should service be necessary under this warranty for any reason due to manufacturing defect or  
malfunction, JL AUDIO will (at its discretion), repair or replace the defective product with new or remanufactured  
product at no charge. Damage caused by the following is not covered under warranty: accident, misuse, abuse,  
product modification or neglect, failure to follow installation instructions, unauthorized repair attempts,  
misrepresentations by the seller.This warranty does not cover incidental or consequential damages and does not  
cover the cost of removing or reinstalling the unit(s). Cosmetic damage due to accident or normal wear and tear  
is not covered under warranty.  
Warranty is void if the products serial number has been removed or defaced.  
Any applicable implied warranties are limited in duration to the period of the express warranty as provided  
herein beginning with the date of the original purchase at retail, and no warranties, whether express or implied,  
shall apply to this product thereafter. Some states do not allow limitations on implied warranties, therefore these  
exclusions may not apply to you.This warranty gives you specific legal rights, and you may also have other rights  
which vary from state to state.  
If you need service on your JL AUDIO product:  
All warranty returns should be sent to JL AUDIO ’s Amplifier Service Facility freight-prepaid through an  
authorized JL AUDIO dealer and must be accompanied by proof of purchase (a copy of the original sales receipt).  
Direct returns from consumers or non-authorized dealers will be refused unless specifically authorized by  
JL AUDIO with a valid return authorization number.  
Warranty expiration on products returned without proof of purchase will be determined from the  
manufacturing date code. Coverage may be invalidated as this date is previous to purchase date. Non-defective  
items received will be returned freight-collect. Customer is responsible for shipping charges and insurance in  
sending the product to JL AUDIO. Freight damage on returns is not covered under warranty.  
For Service Information in the U.S.A. please call:  
JL Audio customer service: (954) 443-1100  
during normal business hours (9:00 AM – 5:30 PM Eastern Time)  
JL Audio, Inc  
10369 North Commerce Pkwy.  
Miramar, FL 33025  
(do not send product for repair to this address)  
InternationalWarranties:  
Products purchased outside the United States of America are covered only  
by that country’s distributor and not by JL Audio, Inc.  
Absolute Symmetry Class AB Amplifier Circuit is covered by U.S. Patent #6,294,959 and is  
pending in the countries listed below. Austria,Belgium,Brazil,Canada,China,France,Germany,Indonesia,  
Italy, Japan, Republic of Korea, Mexico, Netherlands, Norway, Russian Federation, Singapore, Sweden,  
Switzerland, United Kingdom, and all other PCT countries.  
JL3002MAN-CH-04-2003  
 

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