owner’s manual

four-channel full-range amplifier

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.
Protect Your Hearing! Installation Applications
We value you as a long-term customer. For This amplifier is designed for operation in Cooling Efficiency Considerations: If mounting the amplifier under a seat,
that reason, we urge you to practice restraint in vehicles with 12V, negative-ground electrical Your JL Audio amplifier employs an make sure there is at least 1 inch (2.5 cm) of
the operation of this product so as not to damage systems. Use of this product in vehicles with advanced type of heat management, called space above the amplifier’s outer shell to permit
your hearing and that of others in your vehicle. positive ground and/or voltages other than 12V RealSink™. This feature takes advantage of proper cooling.
Studies have shown that continuous exposure to may result in damage to the product and will void convection and radiation effects to remove
high sound pressure levels can lead to permanent the warranty. heat from the amplifier circuitry. For optimum Safety Considerations:
(irreparable) hearing loss. This and all other This product is not certified or approved for cooling performance, the vertical heat sinks Your amplifier needs to be installed in a dry,
high-power amplifiers are capable of producing use in aircraft. located at the back of the amplifier should be well-ventilated environment and in a manner
such high sound pressure levels when connected Do not attempt to “bridge” the outputs of this exposed to as large a volume of air as possible. which does not interfere with your vehicle’s safety
to a speaker system. Please limit your continuous amplifier with the outputs of a second amplifier, Enclosing the amplifier in a small, poorly equipment (air bags, seat belt systems, ABS brake
exposure to high volume levels. including an identical one. ventilated chamber can lead to excessive heat systems, etc.). You should also take the time to
While driving, operate your audio system in build-up and degraded performance. If an securely mount the amplifier using appropriate
a manner that still allows you to hear necessary Planning Your Installation installation calls for an enclosure around the hardware so that it does not come loose in the
noises to operate your vehicle safely (horns, It is important that you take the time to read amplifier, we recommend that this enclosure event of a collision or a sudden jolt to the vehicle.
sirens, etc.). this manual and that you plan out your be ventilated with the aid of a fan. In normal
installation carefully. The following are some applications, fan-cooling is not necessary, but Stupid Mistakes to Avoid:
Serial Number considerations that you must take into account you still need to follow some basic guidelines: • Check before drilling any holes in your
In the event that your amplifier requires when planning your installation. • Amplifier mounted vertically with heat sink fins vehicle to make sure that you will not be
service or is ever stolen, you will need to pointing up: Optimum drilling through a gas tank, brake line, wiring
have a record of the product’s serial number. • Amplifier mounted horizontally, harness or other vital vehicle system.
Please take the time to enter that number in right side up: Good
the space provided below. The serial number • Amplifier mounted horizontally, but upside • Do not run system wiring outside or underneath
can be found on the bottom panel of the down: Fair (not recommended if there is the vehicle. This is an extremely dangerous
amplifier and on the amplifier packaging. less than 1 inch (2.5 cm) clearance above the practice which can result in severe damage to
amplifier heat sinks) your vehicle and person.
Serial Number: • Amplifier mounted vertically with heat sink fins
pointing laterally: Fair • Protect all system wires from sharp metal
• Amplifier mounted vertically with heat sink fins edges and wear by carefully routing them,
pointing down: Poor (not recommended) tying them down and using grommets and
loom where appropriate.

• Do not mount the amplifier in the engine

Chassis Ground
Rear Channel
Filter Slope
Rear Channel
Input Sensitivity
Front Channel
Filter Slope
Front Channel
Input Sensitivity
compartment, under the vehicle, on the roof
Connector Selection Control Selection Control
or in any other area that will expose the
(pg. 5) Rear Channel (pg. 8) Rear Channel (pg. 6) Front Channel (pg. 8) Front Channel (pg. 7) Front Channel
+12 V Power Remote Turn-On Filter Frequency Input Voltage Rear Channel Filter Frequency Input Voltage Input Mode Front Channel amplifier circuitry to the elements.
Connector Connector Range Selector Range Selector Speaker Outputs Range Selector Range Selector Selector Speaker Outputs
(pg. 5) (pg. 6) (pg. 8) (pg. 6) (pg. 9) (pg. 8) (pg. 6) (pg. 6) (pg. 9)

+12VDC Ground Remote Rear Filter Controls Rear Input Section Rear Speaker Outputs Front Filter Controls Front Input Section Front Speaker Outputs
Freq. Range Filter Slope Input Voltage Input Sens. Freq. Range Filter Slope Input Voltage Input Sens. Input Mode

x1 | x10 12dB | 24dB Low | High x1 | x10 12dB | 24dB Low | High 2ch | 4ch
95 95
75 130 Filter Mode 75 130 Filter Mode

300/4v2 60 200
Left Right
60 200
Left Right
Four-Channel Full-Range Amplifier 50 500 Off | LP | HP 50 500 Off | LP | HP

Filter Freq. (Hz) Left Ch. Right Ch. Bridged Filter Freq. (Hz) Left Ch. Right Ch. Bridged

Rear Channel Rear Channel Rear Channel Front Channel Front Channel Front Channel
Filter Cutoff Filter Mode Left and Right Filter Cutoff Filter Mode Left and Right
Frequency Selector Selector Input Jacks Frequency Selector Selector Input Jacks
(pg. 8) (pg. 7) (pg. 6) (pg. 8) (pg. 7) (pg. 6)

2 | JL Audio - 300/4v2 Owner’s Manual 3

Product Description Power Connections
The JL Audio 300/4v2 is a four-channel full-   3) Connect power wire to the positive battery Before installing the amplifier, The ground connection should be made using
range amplifier utilizing patented Absolute post. Fuse the wire with an appropriate fuse disconnect the negative (ground) wire the same gauge wire as the power connection
from the vehicle’s battery. This will prevent
Symmetry™ Class A/B technology for all block (and connectors) within 18 inches (45 and should be kept as short as possible, while
accidental damage to the system, the vehicle
channels. All channels benefit from JL Audio’s cm) wire length of the positive battery post. accessing a solid piece of sheet metal in the
and your person during installation.
exclusive R.I.P.S. power supply design which This fuse is essential to protect the vehicle. Do vehicle. The surface of the sheet metal should
optimizes the output of each channel pair for any not install the fuse until the power wire has be sanded at the contact point to create a clean,
impedance between 1.5 and 4 ohms per channel. been connected to the amplifier. +12VDC Ground Remote Rear Filter Controls metal-to-metal
Rear Inputconnection
Section between the
Rear Speaker chassis Front Filter C
Outputs
The 300/4v2 can be operated in the   4) Run signal cables (RCA cables) and remote Freq. Range Filterand
Slope theInput
termination of the ground wire. For
Voltage Input Sens. Freq. Range F

following modes: turn-on wire from the source unit to the optimal grounding, we recommend the use of a
x1 | x10 12dB | 24dB Low | High x1 | x10 1
amplifier mounting location. 95 JL Audio ECS master ground lug (XB-MGLU). 95
75 130 Filter Mode 75 130 F
1) As a full-system amplifier in bi-amp mode with   5) Run speaker wire from the speaker systems to Alternatively, a sheet metal screw or bolt can be 60
300 /4v2 60 200
Left Right
200

one pair of channels driving subwoofers in low- the amplifier mounting location. Four-Channel Full-Range Amplifier 50 500 Off | used
LP | HP with a star washer. 50 500 O

pass mode (75W x 2 or 150W x 1) and the other   6) F  ind a good, solid metal grounding point close Filter Freq. (Hz) Any wires
Left Ch. runRight
through
Ch. metal barriers
Bridged (such as Filter Freq. (Hz)

pair of channels driving main speakers in high- to the amplifier and connect the negative power firewalls), must be protected with a high quality
pass mode (75W x 2). wire to it using appropriate hardware. Use insulating grommet to prevent damage to the
2) As a four-channel satellite amplifier in a minimum 8 AWG power wire, no longer than The 300/4v2’s “+12 VDC” and “Ground” insulation of the wire. Failure to do so may result
bi-amplified system, delivering high-passed 36 inches (90 cm) from the amplifier to the connections are designed to accept 8 - 4 in a dangerous short circuit.
signals to front and rear speaker systems. ground connection point. In some vehicles, it AWG power wire. 8 AWG is the minimum
may be necessary to upgrade the battery ground recommended power wire size for this amplifier.
The 300/4v2’s flexible input and crossover wire. (See page 5 for important notice). If you are installing the 300/4v2 with other ! IMPORTANT
sections permit operation with a wide variety   7) Securely mount the amplifier using amplifiers and wish to use a single main power Many vehicles employ small (10 AWG -
of source units and system configurations. The appropriate hardware. wire, use 2 AWG or 1/0 AWG main power wire 6 AWG) wire to ground the battery to the
300/4v2 can operate with a single pair of stereo   8) Connect the positive and negative power (depending on the overall current demands of vehicle chassis and to connect the alternator’s
inputs or with separate inputs for front and rear wires to the amplifier. A fuse near the all the amplifiers in the system). This 2 AWG positive connection to the battery. To prevent
channels, if the source unit is equipped with front amplifier is not necessary. or 1/0 AWG power wire should terminate into voltage drops, these wires should  be upgraded
and rear outputs.   9) Connect the remote turn-on wire a distribution block mounted as close to the to 4 AWG when installing amplifier systems
to the amplifier. amplifiers as possible and should connect to the with main fuse ratings above 60A.
Typical Installation Sequence 10) Connect the RCA input cables 300/4v2 with 8 - 4 AWG power wire.
The following represents the sequence to the amplifier. Fuse Requirements
for a typical amplifier installation, using an 11) C  onnect the speaker wires to the amplifier. Note: that smaller AWG numbers mean bigger It is absolutely vital that the main power
aftermarket source unit or OEM Interface 12) C  arefully review the amplifier’s control wire and vice-versa (1/0 AWG is the largest, lead to the amplifier(s) in the system be fused
processor (like the CleanSweep® CL441dsp). settings to make sure that they are set 2 AWG is smaller, then 4 AWG, then within 18 inches (45 cm) of the positive battery
Additional steps and different procedures may according to the needs of the system. 8 AWG, etc.). post connection. The fuse value at each power
be required in some applications. If you have 13) Install power wire fuse (40A for a wire should be high enough for all of the
any questions, please contact your authorized single 300/4v2) and reconnect the negative To connect the power wires to the amplifier, equipment being run from that power wire.
JL Audio dealer for assistance. battery post terminal. first back out the set screw on the top of the If only the 300/4v2 is being run from
14) Turn on the source unit at a low level amplifier, using the supplied 2.5 mm hex that power wire, we recommend a 40A fuse
  1) D
 isconnect the negative battery post to double-check that the amplifier is wrench. Strip 1/2 inch (12 mm) of insulation be used. AGU (big glass fuse), MaxiFuse™
connection and secure the disconnected cable configured correctly. Resist the temptation from the end of each wire and insert the bare (big plastic-body fuse) or AFS (mini-
to prevent accidental re-connection during to crank it up until you have verified the wire into the receptacle on the front panel blade fuse) types are recommended.
installation. This step is not optional! control settings. of the amplifier, seating it firmly so that no No fuse is required or recommended directly
  2) R
 un power wire (minimum 8 AWG) 15) Make necessary adjustments to the input bare wire is exposed. While holding the wire before the amplifier power connection. If one is
from the battery location to the amplifier sensitivity controls to obtain the right in place, tighten the set screw firmly, taking desired, we recommend the use of a 40A AGU,
mounting location, taking care to overall output and the desired balance care not to strip the head of the screw. AFS or MaxiFuse™ type fuse.
route it in such a way that it will not be in the system. See Appendix A (page 14)
damaged and will not interfere with for the recommended input sensitivity
vehicle operation. Use 2 AWG or 1/0 setting method.
AWG power wire if additional amplifiers 16) E
 njoy the fruits of your labor with your
are being installed with the 300/4v2. favorite music.

4 | JL Audio - 300/4v2 Owner’s Manual 5

 Turn-On Lead ! IMPORTANT CROSSOVER CONTROLS
The 300/4v2 uses a conventional +12V remote 1) Input Mode Switch: If you wish to operate The output of the amplifier will decrease Crossovers are groups of individual electronic
turn-on lead, typically controlled by the source all four channels of the 300/4v2 with a single for a given input voltage when the “Input filters which allow only certain frequency
unit’s remote turn-on output. The amplifier will pair of stereo inputs, select the “2ch” position Range” switch is placed in the “High” ranges to pass through them by attenuating
turn on when +12V is present at its “Remote” on the “Input Mode” switch and connect a position. Conversely, the output will be frequencies outside the selected range. These
input and turn off when +12V is switched off. If single pair of input cables to the input jacks higher with the switch in the “Low” position. filters allow the user to specify what frequency
a source unit does not have a dedicated remote in the “Front Input Section”. In this mode, While this may sound counter-intuitive, it is range will be sent out of each channel section
turn-on output, the amplifier’s turn-on lead can the amplifier will route the signals connected correct as described. of the amplifier. This, in turn, allows each
be connected to +12V via a switch that derives to the front inputs to the rear inputs as well. speaker system to only reproduce a range of
power from an ignition-switched circuit. If you wish to use separate inputs for the front 3) Input Sensitivity Adjustment: Located next frequencies it is well-suited for, resulting in
The 300/4v2’s “Remote” turn-on connector is and rear channel sections (to allow front-to- to the “Input Voltage” switch in each input reduced distortion and improved fidelity.
designed to accept 18 AWG – 8 AWG wire. rear fading, for example) and the source unit section is a rotary control labeled “Input
12 AWG is more than adequate for this purpose. is equipped with front and rear outputs, select Sens.”. Once the appropriate “Input Voltage” Front And Rear Filter Section:
To connect the remote turn-on wire to the “4ch” on the “Input Mode” switch. In this range has been selected, this control can be
amplifier, first back out the set screw on the top mode, you must connect separate pairsGround
+12VDC of input
Remote RearusedFilterto match theRear
Controls source
Input unit’s
Section outputRearvoltage
Speaker Outputs
+12VDC Ground Front FilterRemote
Controls FrontRear Input
FilterSection
Controls RearFront
InputSp S
of the amplifier, using the supplied hex wrench. cables to each input section. Freq.to the input
Range Filter Slopestage ofVoltage
Input each Input
pairSens.
of amplifier Freq. Range Filter Slope Input VoltageFreq.Input
Range Sens. FilterInput
Slope
Mode Input Voltage In

Strip 1/2 inch (12mm) of wire and insert the channels for maximum clean output. Rotating
x1 | x10 12dB | 24dB Low | High x1 | x10 12dB | 24dB Low | High x1 | x10 12dB |2ch | 4ch
24dB Low | High
bare wire into the receptacle on the front panel 2) Input Voltage Range: A wide range of signal the
95 control clockwise will result in higher 95 95
75 130 Filter Mode 75 130 Filter Mode 75 130 Filter Mode
of the amplifier, seating it firmly so that no bare input voltages can be accommodated by each of sensitivity (louder for a given input voltage).
300 /4v2 60 200 60
300200/4v2 60 200

wire is exposed. When using smaller wire, it may the 300/4v2’s input sections (200mV – 8V).
Four-Channel Full-Range Amplifier 50 Rotating 500 Off | LPthe| HP control counter-clockwise will
Left Right
Four-Channel Full-Range
50 500 Amplifier
Off | LP | HP 50 500 Off | LP | HP
Left

be necessary to strip 1 inch of insulation from This wide range is split up into two sub-ranges, Filter result
Freq. (Hz) in lower sensitivity Left Ch. (quieter
Right Ch. for a given Bridged Filter Freq. (Hz) Left Ch.Filter Freq.
Right
(Hz)
Ch. Left Ch. RB

the wire and fold the bare wire in half prior to accessible via switches located in each input input voltage). To properly set each pair
insertion. While holding the wire in the terminal, section of the amplifier. Be aware that each of amplifier channels for maximum clean
tighten the set screw firmly, taking care not to input section’s “Input Voltage” switch will output, please refer to Appendix A (page 14) The 300/4v2 employs two separate, but
strip the head of the screw and making sure that have to be configured, regardless of how many in this manual. After using this procedure, identical filter sections for its front and rear
the wire is firmly gripped by the set screw. input cables are actually feeding the amplifier. you can then adjust the relative level of each channel pairs. These sections consist of the
The “Low” position on each “Input Voltage” channel pair by adjusting the input sensitivity following controls
FRONT AND  REAR Input Sections switch selects an input sensitivity range downward on either or both channel pairs, if
The 300/4v2 has two separate input sections, between 200mV and 2V. This means that the they require attenuation to achieve the desired 1) “Filter Mode” Control: This switch allows you
one for its front channels and another for its rear “Input Sens.” rotary control will operate system balance. Do not increase the “Input to configure the filter into one of two filter
channels. Each section contains a pair of RCA- within that voltage window. If you are using an Sens.” setting for any amplifier in the system types or to defeat it completely:
type input jacks, an “Input Voltage” switch and aftermarket source unit, with conventional beyond the maximum level established during
an “Input Sens.” rotary control. preamp-level outputs, this is most likely the the procedure outlined in Appendix A (page “Off”: Defeats the filter for that channel
position that you will use. The “High” position 14). Doing so will result in audible distortion section completely, allowing the full range of
on each “Input Voltage” switch selects an and possible speaker damage. Be aware that frequencies present at the inputs to feed that
nd
r Controls
Remote Front Input
Rear
Section
Filter Controls Front
RearSpeaker
Input Section
Outputs inputOutputs
Rear Speaker sensitivityFront
range between
Filter Controls 800mV Front and Input
8V. Section Frontboth Speaker OutputsSens.” adjustments will have to
“Input pair of channels. This is useful for systems
Filter Slope Input Voltage InputFreq.
Sens.Range
InputFilter
ModeSlope Input Voltage Input Sens. This is useful forFreq.certain
Range high-output
Filter Slope Input preamp
Voltage Input Sens. Input Mode be made, regardless of how many input cables utilizing outboard crossovers or requiring full-
level signals as well as speaker-level output are feeding the amplifier. These controls will range reproduction from that pair of channels.
12dB | 24dB Low | High x1 | x10 2ch12dB
| 4ch | 24dB Low | High x1 | x10 12dB | 24dB Low | High 2ch | 4ch
95 from source units and 95 small amplifiers. To use allow you to set the appropriate relative levels
Filter Mode 75 130 Filter Mode 75 130 Filter Mode
speaker-level sources, splice the speaker output for front and rear channels and any other “LP” (Low-Pass): Configures the filter to
300/4
0
v2 60 200
Left Right Left
60 200

Range
Off | LP Amplifier
| HP 50 500 Off | LP | HP wires Right
of the source
50 unit500 orOff |small
LP | HP amplifier onto
Left
amplifier Right
channels in the system. attenuate frequencies above the selected
Left Ch. Right
Filter
Ch.
Freq. (Hz) Bridged
Left Ch. Right Ch. a pair of RCA plugs
Bridged for
Filter Freq. (Hz) each input pair or useRight Ch.
Left Ch. Bridged filter frequency. Useful for connection of
the JL Audio ECS Speaker Wire to RCA subwoofer(s) to that channel section.
adaptor (XB-CLRAIC2-SW).
The “Front Input Section” also contains an “HP” (High-Pass): Configures the filter to
“Input Mode” switch to allow operation of all attenuate frequencies below the selected
four amplifier channels with one or two pairs of filter frequency. Useful for connection
input signals. of component speakers to that channel
section in a bi-amplified system.

6 | JL Audio - 300/4v2 Owner’s Manual 7

 Speaker
+12VDC OUTPUTS
Ground Remote Rear Filter Controls Rear Input Section Rear Speaker Outputs Front Filter Controls Bridging
Front Input Section Considerations Front Speaker Outputs
2) “Filter Slope” Control: This switch allows you Even though you may have installedFreq. zillions
Range
of
Filter Slope Input Voltage Input Sens. Freq. Range Filter Slope
BridgingInput
Input Voltage Input Sens.
is the
Mode
practice of combining the
to select from two filter slopes for that channel amps in your day, please take the time to |read this| output of two amplifier channels to drive a single
x1 x10 12dB 24dB Low | High x1 | x10 12dB | 24dB Low | High 2ch | 4ch
section. section! The 300/4v2 is not a typical amplifier 95 and 95 load. When bridged, each channel produces
75 130 Filter Mode 75 130 Filter Mode
care must be taken to balance the front and rear signals of equal magnitude, but opposite polarity.
300 /4v2 60 200
Left Right
60 200
Left Right
“12dB”: Configures the filter to attenuate channel speaker
Four-Channel impedances
Full-Range Amplifier for optimum 50 output
500 Off | LP | HP 50 500 Off | LP | HP The combined output of the two channels
frequencies above or below the selected from all four channels. Filter Freq. (Hz) Left Ch. Right Ch. Bridged Filter Freq. (Hz) Left Ch. provides
Right Ch. twice the output voltage available from a
Bridged

filter frequency at a rate of 12 dB per octave The 300/4v2 employs JL Audio’s exclusive single channel. The 300/4v2 has been designed for
(Butterworth alignment). Regulated, Intelligent Power Supply (R.I.P.S.) bridging of its channel pairs without the need for
design. This sophisticated power supply allows input inversion adaptors.
“24dB”: Configures the filter to attenuate the amplifier to produce its optimum power (300 ! IMPORTANT
frequencies above or below the selected watts) over a wide range of speaker impedances. For optimum power output at all four channels,
filter frequency at a rate of 24 dB per octave +12VDC Ground
UnlikeRemote
conventional amplifiers Rear Filterthat require aRear Input Section
Controls Rearconnect the same impedance
Speaker Outputs Front Filter Controls (between 1.5-4Ω) Front Input Section Front Speaker Outputs
(Linkwitz-Riley alignment). specific impedance to produce Freq. Rangeoptimum
Filter Slope power, Input Voltage Input Sens. on all four channels. Freq. On
Range pages 16 and
Filter Slope 17
Input are Input Sens. Input Mode
Voltage

the R.I.P.S.-equipped 300/4v2 gives you the charts showing the continuous (RMS) power
x1 | x10 12dB | 24dB Low | High x1 | x10 12dB | 24dB Low | High 2ch | 4ch
Depending on the speaker system and the freedom to use a variety of speaker 95 configurations output capability of the 95 300/4v2 into various
75 130 Filter Mode 75 130 Filter Mode
vehicle, different filter slopes may be required that achieve final impedances between 1.5 – 4 combinations of front and rear impedances
300/4v2 60 200 60 200

to produce a smooth transition between the Four-Channel Full-Range

Ohms nominal
Amplifier per channel 50 (without
500 Off | LP sacrificing
| HP (optimum
Left
output is
Right
50 shown 500 Offin| LPbold
| HP type). Please Left Right

sound of different speakers in the system. power output or sound quality).Filter Freq. (Hz) Left Ch. Right Ch. refer to these charts
Bridged Filter so
Freq. you
(Hz) know whatLefttoCh.expect Right Ch. Bridged

Experiment to find the slope which best matches The operation of the R.I.P.S. circuitry is in terms of power output.
the acoustic requirements of the system. The entirely automatic and adjusts itself every time
sharper “24dB” setting will do a better job of the amplifier is turned on according to the To bridge a pair of channels, use the “Left +”
protecting small speakers with limited power lowest impedance present at either front or rear ! IMPORTANT and “Right –” speaker connectors only (the “Left
handling. The shallower “12dB” octave setting channels. There are no user controls to configure. If you connect a load higher than 4Ω nominal –” and “Right +” remain unused). Then connect
allows for greater energy overlap with the rest of The system operates through three stages of per channel in stereo mode (or 8Ω in bridged a mono signal to both left and right RCA inputs
the speaker system. In some cases, this results impedance optimization, choosing the stage mode), power will drop by half with every for that channel pair. This requires an RCA
in better overall response and sound quality. most appropriate to the actual impedance of the doubling of impedance above 4Ω stereo / 8Ω “Y-Adaptor” like the JL Audio ECS model
speakers connected to it. mono. If you connect a load lower than 1.5Ω XB-CLRAICY-1F2M (sold separately).
3) “Freq. Range” Control: When thrown to Because the 300/4v2 utilizes a single power nominal per channel in stereo mode (or 3Ω in When bridged, each channel pair will
the right, this switch multiplies the cutoff supply, it will set itself up based on the lowest bridged mode, the amplifier protection deliver optimum power into a 3-8Ω load.
frequency selected by the rotary “Filter Freq. impedance present at either the front or rear circuitry activates a “safe” mode which reduces Operating bridged channel pairs into a load
(Hz)” control by a factor of 10. In the “x1” amplifier channels. For example, if you connect amplifier power to protect the circuitry from lower than 3Ω is not recommended.
position, the range of the rotary control is a 2 ohm load to each front channel and a 4 ohm failure (the yellow “Low Ω” LED lights to Because a bridged pair of channels requires
50 - 500 Hz (as marked). In the “x10” load to each rear channel, the amplifier will indicate that this has happened). See page 10 that both channels receive input, you need to
position, the range of the rotary control is adjust itself to deliver 75 watts x 2 to the front 2 for details. connect both left and right RCA inputs to the
500 Hz - 5 kHz (5000 Hz). ohm loads, but will only deliver half its optimum bridged channel pair’s inputs. Connection of
power (37.5 watts x 2) to the rear 4 ohm loads. If only one RCA input will result in reduced power
4) “Filter Freq. (Hz)” The filter frequency you connect a 4 ohm load to all four channels or a ! IMPORTANT output, increased distortion and can cause the
markings surrounding this rotary control 2 ohm load to all four channels, the amplifier will Speaker loads below 1.5Ω nominal per channel amplifier to overheat. Do not do this! Instead, use
are for reference purposes and are generally deliver 75 watts x 4. See, we told you this amp in stereo or 3Ω nominal in bridged mode are a “Y-Adaptor” to split the mono signal into both
accurate to within 1/3 octave or better. If you was different... Read on, there is more important not recommended and may cause the amplifier left and right RCA inputs.
would like to select the filter cutoff frequency information to follow. output to distort excessively.
with a higher level of precision, consult the
charts in Appendix A (page 14) of this manual.

8 | JL Audio - 300/4v2 Owner’s Manual 9

Status Indicator Lights / Servicing your JL Audio Amplifier SYSTEM CONFIGURATIONS
Protection Circuitry If your amplifier fails or malfunctions, please The 300/4v2 is a flexible amplifier, well-suited B) Fade Subwoofer Level vs. HF Level
There are three status indicator lights on the return it to your authorized JL Audio dealer so for a multitude of system configurations. In Required: a source unit or processor with front
top of the amplifier. These are as follows: that it may be sent in to JL Audio for service. this section, the most likely configurations are and rear pairs of outputs.
There are no user serviceable parts or fuses inside explained in detail. Input Connections: the first stereo pair of source
1) “Power” (Green): lights to indicate that the the amplifier. The unique nature of the circuitry Once you have selected your desired unit outputs is connected to the front inputs
amplifier is turned on and operating normally. in the JL Audio amplifiers requires specifically configuration, you can use the amplifier panel of the 300/4v2. The second stereo pair of
trained service personnel. Do not attempt drawings on Page 22 to mark the required switch source unit outputs is connected to the rear
2)“Thermal” (Red): lights to indicate that to service the amplifier yourself or through positions for easy reference. inputs (select “4ch” on the “Input Mode”
the amplifier has exceeded its safe operating unauthorized repair facilities. This will not only switch in the “Front Input Section”).
temperature, putting the amplifier into a self- void the warranty, but may result in the creation Bi-AmpLIFIED SYSTEMS Result: in this mode, the user has the ability to
protection mode, which reduces the power of more problems within the amplifier. Bi-amplified systems are defined as systems fade or control the level of the LF channels
output of the amplifier. The red light will shut in which separate amplifier channels drive low- relative to the HF channels via the source
off and the amplifier will return to normal, frequency (LF) and high-frequency (HF) speakers unit’s fader control without exceeding the
full-power operating mode if the heat sink and are separately filtered to send appropriate maximum clean output level set by each
temperature drops back to a safe level. frequency ranges to each speaker system. amplifier section’s “Input Sens.” controls.
If you have any questions about the installation or The most common application of
3) “Low Ω” (Amber): lights to indicate that the setup of the amplifier not covered in this manual, bi-amplification in mobile audio is to drive a C) Subwoofer Level Control Only
impedance of the speaker load connected to please contact your dealer or technical support. subwoofer system from one or more amplifiers or Required: a source unit or processor with left,
the amplifier is lower than the optimum load channels and component speakers from separate right and subwoofer outputs.
impedance range for the amplifier. When this JL Audio Technical Support: amplifiers or channels. Input Connections: the main stereo pair of
light is on, a protection circuit engages and (954) 443-1100 The 300/4v2 can be configured to drive a source unit outputs is connected to the front
reduces the power output of the amplifier. 9:00 AM – 5:30 PM (Eastern Time Zone) bi-amplified system by itself or with a separate inputs of the 300/4v2. The source unit’s
The amber indicator will also light when a Monday - Friday subwoofer amplifier. dedicated subwoofer output is connected to
short-circuit is detected in the speaker wiring the rear inputs (select “4ch” on the “Input
(this can be a short between the positive and Bi-Amplified System With One 300/4v2 Mode” switch in the “Front Input Section”).
negative speaker wires or between either In this configuration, the rear channels of the Result: in this mode, the user has the ability to
speaker wire and the vehicle chassis). 300/4v2 will drive subwoofers (stereo 75W x 2 or control the absolute level of the LF channels
bridged 150W x 1) with low-pass filtering. The relative to the HF channels.
There is only one condition that will shut front channels will drive component speakers in
down an undamaged 300/4v2 completely… If stereo (75W x 2) with high-pass filtering.
battery voltage drops below 10 volts, the entire ! IMPORTANT
amplifier will shut itself off. The green “Power” Input connection options for a bi-amplified system Set the rear channel “Input Sens.” with the
indicator on the top of the amplifier will turn with one 300/4 v2 are as follows: source unit’s subwoofer level control set at
off when this occurs. The amplifier will turn 3/4 of full output. See Appendix A (page 14)
back on when voltage climbs back above 10 volts. A) No User Adjustability: for details.
This may happen in a rapid cycle when bass- Required: a basic source unit or processor with
heavy program material causes a weak charging one pair of stereo outputs.
system to dip below 10 volts momentarily. If this Input Connections: a single pair of stereo
is happening in your system, have your charging source unit outputs connected to the
system inspected to make sure it is working front channel inputs of the 300/4v2
properly. (select “2ch” on the “Input Mode”
For information on troubleshooting this switch in the “Front Input Section”).
amplifier, refer to Appendix E (page 20). Result: the relative level of the LF and HF
channels will be fixed by the 300/4v2’s “Input
Sens.” settings and will not be user adjustable
from the front of the vehicle.

10 | JL Audio - 300/4v2 Owner’s Manual 11

Crossover Setup for Bi-Amplified System Input connection options for a bi-amplified C) Subwoofer Level Control Only ! IMPORTANT
with one 300/4v2: system with one 300/4v2 and a separate subwoofer Required: a source unit or processor with left, Set the subwoofer amplifier’s “Input Sens.”
amplifier are as follows: right and dedicated subwoofer outputs. with the source unit’s subwoofer level control
Once the input sections have been configured Input Connections: The main stereo pair of set at 3/4 of full output.
appropriately, go to the “Rear Filter Controls”. A) No User Adjustability: source unit outputs is connected to the
Select “x1” on the “Freq. Range” switch, “LP” Required: a basic source unit or processor with front inputs of the 300/4v2 (select “2ch” Crossover Setup for Bi-Amplified System with one
(low-pass) on the “Filter Mode” switch and left and right stereo outputs. on the “InputMode” switch in the “Front 300/4v2 and a separate subwoofer amplifier:
“12dB” or “24dB” on the “Filter Slope” switch Input Connections: a single pair of stereo Input Section”). The source unit’s dedicated
and an appropriate “Filter Freq.” (80-90 Hz is a source unit outputs is connected to the subwoofer output is connected to the Once the input and preamp output
good starting point). front inputs of the 300/4v2 (select “2ch” subwoofer amplifier inputs. sections have been configured appropriately,
Next, turn your attention to the “Front Filter on the “Input Mode” switch in the “Front Result: with this option, the user has the ability go to the “Front Filter Controls” and
Controls” and select “x1” on the “Freq. Range” Input Section”) and also connected to the to control the absolute level of the subwoofer “Rear Filter Controls” You will set both
switch, “HP” (high-pass) on the “Filter Type” subwoofer amplifier inputs via a pair of channel relative to the HF channels, but control sections identically to start:
switch and “12dB” or “24dB” on the “Filter “Y-Adaptors” like the JL Audio ECS model cannot fade the front and rear HF channels Select “x1” on the “Freq. Range” switch, “HP”
Mode/Slope” switch and an appropriate “Filter XB-CLRAICY-1F2M. Alternatively, the relative to each other. (high-pass) on the “Filter Mode” switch and
Freq.” (again, 80-90 Hz is a good starting point). 300/4v2 can receive its input from the “12dB” or “24dB” on the “Filter Slope” switch
After proper adjustment of the front and rear subwoofer amplifier’s preamp output set and an appropriate “Filter Freq.” (80 - 90 Hz is a
“Input Range” and “Input Sens.” controls using to “full-range” mode. ! IMPORTANT good starting point). Select the same settings for
the method shown in Appendix A (page 14), you Result: the relative level of the LF and front Set the subwoofer amplifier’s “Input Sens.” the “Rear Filter Controls”.
can fine tune filter frequencies and slopes and and rear HF channels will be fixed by with the source unit’s subwoofer level control After proper adjustment of the 300/4v2’s
attenuate either pair of channels to achieve proper the 300/4v2’s “Input Sens.” settings set at 3/4 of full output. front and rear “Input Sens.” controls and the
balance. For precise filter frequency information (as well as the subwoofer amplifier’s subwoofer amplifier’s input sensitivity controls,
refer to Appendix D (page 18). settings) and will not be user adjustable D) Front to Rear HF Fading and you can fine tune filter frequencies and slopes and
from the front of the vehicle. Subwoofer Level Control attenuate either pair of channels to achieve proper
Required: a source unit or processor with balance. For proper adjustment of the “Input
Bi-Amplified System with one 300/4v2 in B) Fade Subwoofer Level vs. HF Level front and rear pairs of stereo outputs plus a Sens.” controls of the 300/4v2 use the method
four-channel mode and a separate Required: a source unit or processor with front dedicated subwoofer output. shown in Appendix A (page 14). For precise filter
subwoofer amplifier and rear pairs of stereo outputs. Input Connections: one stereo pair (front, frequency information for the 300/4v2 refer to
This configuration requires that the separate Input Connections: one stereo pair of source unit typically) of source unit outputs is connected Appendix D (page 18). Refer to the subwoofer
subwoofer amplifier has a built-in low-pass filter. outputs is connected to the front inputs of the to the front inputs of the 300/4v2. The second amplifier owner’s manual for proper adjustments.
All JL Audio subwoofer amplifiers have this 300/4v2 (select “2ch” on the “Input Mode” stereo pair of source unit outputs (rear,
feature. switch in the “Front Input Section”). The typically) is connected to the rear inputs of
In this configuration, the front channels of second stereo pair of source unit outputs is the 300/4v2 (select “4ch” on the “Input Mode”
the 300/4v2 will drive front component speakers connected to the subwoofer amplifier inputs. switch in the “Front Input Section”). The
(stereo 75W x 2) with high-pass filtering. The rear Result: with this option, the user has the source unit’s dedicated subwoofer output is
channels will drive rear component speakers in ability to fade the level of the subwoofer connected to the subwoofer amplifier inputs.
stereo (75W x 2), also with high-pass filtering. amplifier’s input relative to the HF Result: with this option, the user has the ability
The separate amplifier will drive the subwoofer channels, but cannot control front-to- to fade the front and rear HF channels relative
system with low-pass filtering (select a filter rear fading of the HF channels. The to each other and also has the ability to
frequency of 80-90 Hz to start). relative level of the front and rear HF control the absolute level of the subwoofer
channels will be fixed by the 300/4v2’s channel relative to the HF channels.
“Input Sens.” settings and will not be user
adjustable from the front of the vehicle.
fading the signal to the subwoofer amplifier.

12 | JL Audio - 300/4v2 Owner’s Manual 13

Appendix A: Appendix B:
Input Sensitivity Level Setting 4) Set the source unit volume to 3/4 of full ! IMPORTANT 300/4v2 Specifications
JL Audio amplifiers utilizing the Regulated volume. If either set of channels is being Do not increase any “Input Sens.” setting for
Intelligent Power Supply (R.I.P.S.) allow driven by a source unit’s dedicated subwoofer any amplifier channel or channel pair in the General Specifications:
delivery of their rated power when connected output, also adjust the source unit’s subwoofer system beyond the maximum level established Recommended Fuse Value: 40A
to any load impedance from 1.5 - 4Ω per level control to 3/4 of maximum output. This during this procedure. Doing so will result in Recommended Fuse Type: AFS, AGU or MaxiFuse™
channel and when connected to a charging will allow for reasonable gain overlap with audible distortion and possible speaker damage.
system with any voltage from 11 - 14.5V. This moderate clipping at full volume. Input Sections:
design is beneficial for many reasons. One of 5) Using the listings on pages 16 & 17, find the It will be necessary to re-adjust the No. of Inputs: Two Stereo Pairs (Front, Rear)
these reasons is ease of setup. Because each configuration that matches your specific “Input Sens.” for the affected channels if any Input Type: Differential-balanced with RCA jack inputs
JL Audio amplifier will always deliver the speaker impedance as connected to the equalizer boost is activated after setting the Input Range: Switchable from 200mV - 2V RMS
same amount of power within its operational 300/4v2. Note whether your channels are in “Input Sens.” with this procedure. This applies to 800mV - 8V RMS
range of impedances and supply voltages, the stereo or bridged and use the appropriate to any EQ boost circuit, including source unit
maximum, unclipped output is very predictable. listing section. Once you have found your tone controls or EQ circuits. EQ cuts will not Amplifier Section:
This makes setting the gain structure via the configuration, note the target voltage for input require re-adjustment. Amplifier Topology: Class A/B with patented Absolute
input sensitivity controls very simple. Following sensitivity adjustment for each channel section. Symmetry™ dual N-Channel MOSFET output design
the directions below will allow the user to adjust This target voltage is listed in parentheses as Power Supply: Independent, pulse width modulation-reg-
the input sensitivity of the amplifier(s) simply “(set to “x” volts)”. Please refer to Input Sensitivity Level Setting ulated switching power supply with multistage impedance
and easily in just a few minutes using equipment 6) Verify that you have disconnected the speakers Reference Listings on the next pages. optimizing circuitry.
which is commonly available in installation bays. before proceeding. Play a track with an Rated Power (Stereo):
appropriate sine wave (within the frequency 75W RMS x 4 @ 1.5-4Ω (11V - 14.5V)
Necessary Equipment range to be amplified by each set of channels) Rated Power (Bridged):
• Digital AC Voltmeter at 3/4 source unit volume. 150W RMS x 2 @ 3-8Ω (11V - 14.5V)
• CD with a sine-wave test tone recorded at 7) Connect the AC voltmeter to the “Front THD at Rated Power: <0.03% @ 4Ω per channel
0 dB reference level in the frequency range Speaker Outputs” or “Rear Speaker Outputs” (20 Hz-20 kHz)
to be amplified for that set of channels connectors of the amplifier. If the channel pair Signal to Noise Ratio: >108.5 dB referred to rated power
(50 Hz for subwoofer channels, 1 kHz for is operating in stereo, it is only necessary to (A-weighted, 20 Hz-20 kHz noise bandwidth)
a midrange application). The CleanSweep® measure one channel. If bridged, make sure Frequency Response: 5 Hz - 30 kHz (+0, -1dB)
Calibration Disc contains the appropriate you test the voltage at the correct connectors Damping Factor: >200 @ 4Ω per ch. / 50 Hz, >100 @ 2Ω
test tones and is available for sale at (L+ and R–). per ch. / 50 Hz
http://store.jlaudio.com Do not use attenuated 8) Increase the “Input Sens.” control until Slew Rate: ± 25V/µs
test tones (-10 dB, -20 dB, etc.). the target voltage is delivered for that set of
channels.If excessive voltage is read on either Filter Sections:
The Nine-Step Procedure set of channels with the control at minimum Front and Rear Filters (2): State-variable, 12 dB/octave
(follow this procedure for each pair of channels) (full counterclockwise), switch the appropriate Butterworth or 24 dB/octave Linkwitz-Riley low-pass or
1) D
 isconnect the speaker(s) from the “Input Voltage” switch to “High” and re-adjust. high-pass with continuously variable cutoff frequency
amplifier’s “Front Speaker Outputs” and 9) Once you have adjusted each set of channels from 50 - 500 Hz, switchable to a range of 500 - 5000 Hz,
“Rear Speaker Outputs” connectors. to its maximum low-distortion output level, via x10 switch. Defeatable.
2) T urn off all processing on the source reconnect the speaker(s). The “Input Sens.”
unit (bass/treble, loudness, EQ, etc.). controls can now be adjusted downward if either Dimensions (LxWxH):
Set fader control to center position or both sets of channels requires attenuation to 13.4" x 9.25" x 2.27" (340mm x 235mm x 58mm)
and subwoofer level control to 3/4 of achieve the desired system balance.
maximum (if used to drive the 300/4v2).
3) Switch the “Input Voltage” to “Low” and
turn the “Input Sens.” control on both sets of
channels all the way down.

Due to ongoing product development, all specifications are subject to

change without notice.

14 | JL Audio - 300/4v2 Owner’s Manual 15

Appendix C:
Input Sensitivity Level Setting Reference Listings Sub-Optimum Configurations (Stereo/Bridged):
1) Define your front/rear channel configuration (Stereo/Stereo, Stereo/Bridged or Bridged/Bridged 1st Pair of Channels (Stereo) 2nd Pair of Channels (Bridged)
2) L ook in the “Optimum Configurations” listing for your channel configuration. If it does not appear Stereo 8Ω: 38W x 2 (set to 17.3V / ch.) Bridged 16Ω: 75W x 1 (set to 34.6V)
here, look for it in the “Sub-Optimum Configurations” listing for your channel configuration. Stereo 8Ω: 38W x 2 (set to 17.3V / ch.) Bridged 12Ω: 100W x 1 (set to 34.6V)
3) Once you have found your specific combination of impedances, use the target voltage listed in Stereo 8Ω: 38W x 2 (set to 17.3V / ch.) Bridged 8Ω: 150W x 1 (set to 34.6V)
parentheses for each set of channels to set the “Input Sens.” controls of the 300/4v2. Stereo 8Ω: 25W x 2 (set to 15.0V / ch.) Bridged 6Ω: 150W x 1 (set to 30.0V)
Stereo 8Ω: 19W x 2 (set to 12.3V / ch.) Bridged 4Ω: 150W x 1 (set to 24.6V)
For easy reference, channels achieving optimum power have their power output listed in bold type. Stereo 8Ω: 14W x 2 (set to 10.6V / ch.) Bridged 3Ω: 150W x 1 (set to 21.2V)
Stereo 4Ω: 75W x 2 (set to 17.3V / ch.) Bridged 16Ω: 75W x 1 (set to 34.6V)
Optimum Configurations (Stereo/Stereo): Stereo 4Ω: 75W x 2 (set to 17.3V / ch.) Bridged 12Ω: 100W x 1 (set to 34.6V)
1st Pair of Channels (Stereo) 2nd Pair of Channels (Stereo) Stereo 4Ω: 50W x 2 (set to 15.0V / ch.) Bridged 6Ω: 150W x 1 (set to 30.0V)
Stereo 4Ω: 75W x 2 (set to 17.3 V / ch.) Stereo 4Ω: 75W x 2 (set to 17.3 V / ch.) Stereo 4Ω: 38W x 2 (set to 12.3V / ch.) Bridged 4Ω: 150W x 1 (set to 24.6V)
Stereo 3Ω: 75W x 2 (set to 15.0 V / ch.) Stereo 3Ω: 75W x 2 (set to 15.0 V / ch.) Stereo 4Ω: 28W x 2 (set to 10.6V / ch.) Bridged 3Ω: 150W x 1 (set to 21.2V)
Stereo 2Ω: 75W x 2 (set to 12.3 V / ch.) Stereo 2Ω: 75W x 2 (set to 12.3 V / ch.) Stereo 3Ω: 75W x 2 (set to 15.0V / ch.) Bridged 16Ω: 50W x 1 (set to 30.0V)
Stereo 1.5Ω: 75W x 2 (set to 10.6 V / ch.) Stereo 1.5Ω: 75W x 2 (set to 10.6 V / ch.) Stereo 3Ω: 75W x 2 (set to 15.0V / ch.) Bridged 12Ω: 75W x 1 (set to 30.0V)
Stereo 3Ω: 75W x 2 (set to 15.0V / ch.) Bridged 8Ω: 100W x 1 (set to 30.0V)
Optimum Configurations (Stereo/Bridged): Stereo 3Ω: 50W x 2 (set to 12.3V / ch.) Bridged 4Ω: 150W x 1 (set to 24.6V)
1st Pair of Channels (Stereo) 2nd Pair of Channels (Bridged) Stereo 3Ω: 38W x 2 (set to 10.6V / ch.) Bridged 3Ω: 150W x 1 (set to 21.2V)
Stereo 4Ω: 75W x 2 (set to 17.3 V / ch.) Bridged 8Ω: 150W x 1 (set to 34.6 V) Stereo 2Ω: 75W x 2 (set to 12.3V / ch.) Bridged 16Ω: 38W x 1 (set to 24.6V)
Stereo 3Ω: 75W x 2 (set to 15.0 V / ch.) Bridged 6Ω: 150W x 1 (set to 30.0 V) Stereo 2Ω: 75W x 2 (set to 12.3V / ch.) Bridged 12Ω: 50W x 1 (set to 24.6V)
Stereo 2Ω: 75W x 2 (set to 12.3 V / ch.) Bridged 4Ω: 150W x 1 (set to 24.6 V) Stereo 2Ω: 75W x 2 (set to 12.3V / ch.) Bridged 8Ω: 75W x 1 (set to 24.6V)
Stereo 1.5Ω: 75W x 2 (set to 10.6 V / ch.) Bridged 3Ω: 150W x 1 (set to 21.2 V) Stereo 2Ω: 75W x 2 (set to 12.3V / ch.) Bridged 6Ω: 100W x 1(set to 24.6V)
Stereo 2Ω: 56W x 2 (set to 10.6V / ch.) Bridged 3Ω: 100W x 1(set to 21.2V)
Optimum Configurations (Bridged/Bridged): Stereo 1.5Ω: 75W x 2 (set to 10.6V / ch.) Bridged 16Ω: 28W x 1(set to 21.2V)
1st Pair of Channels (Bridged) 2nd Pair of Channels (Bridged) Stereo 1.5Ω: 75W x 2 (set to 10.6V / ch.) Bridged 12Ω: 38W x 1(set to 21.2V)
Bridged 8Ω: 150W x 1 (set to 34.6 V) Bridged 8Ω: 150W x 1 (set to 34.6 V) Stereo 1.5Ω: 75W x 2 (set to 10.6V / ch.) Bridged 8Ω: 56W x 1(set to 21.2V)
Bridged 6Ω: 150W x 1 (set to 30.0 V) Bridged 6Ω: 150W x 1 (set to 30.0 V) Stereo 1.5Ω: 75W x 2 (set to 10.6V / ch.) Bridged 6Ω: 75W x 1(set to 21.2V)
Bridged 4Ω: 150W x 1 (set to 24.6 V) Bridged 4Ω: 150W x 1 (set to 24.6 V) Stereo 1.5Ω: 75W x 2 (set to 10.6V / ch.) Bridged 4Ω: 112W x 1(set to 21.2V)
Bridged 3Ω: 150W x 1 (set to 21.2 V) Bridged 4Ω: 150W x 1 (set to 21.2 V)
Sub-Optimum Configurations (Bridged/Bridged):
Sub-Optimum Configurations (Stereo/Stereo): 1st Pair of Channels (Bridged) 2nd Pair of Channels (Bridged)
1st Pair of Channels (Stereo) 2nd Pair of Channels (Stereo) Bridged 16Ω: 75W x 1 (set to 34.6V) Bridged 16Ω: 75W x 1 (set to 34.6V)
Stereo 8Ω: 38W x 2 (set to 17.3 V / ch.) Stereo 8Ω: 38W x 2 (set to 17.3 V / ch.) Bridged 16Ω: 75W x 1 (set to 34.6V) Bridged 12Ω: 100W x 1 (set to 34.6V)
Stereo 8Ω: 38W x 2 (set to 17.3 V / ch.) Stereo 6Ω: 50W x 2 (set to 17.3 V / ch.) Bridged 16Ω: 75W x 1 (set to 34.6V) Bridged 8Ω: 150W x 1 (set to 34.6V)
Stereo 8Ω: 38W x 2 (set to 17.3 V / ch.) Stereo 4Ω: 75W x 2 (set to 17.3 V / ch.) Bridged 16Ω: 50W x 1 (set to 30.0V) Bridged 6Ω: 150W x 1 (set to 30.0V)
Stereo 8Ω: 28W x 2 (set to 15.0 V / ch.) Stereo 3Ω: 75W x 2 (set to 15.0 V / ch.) Bridged 16Ω: 38W x 1 (set to 24.6V) Bridged 4Ω: 150W x 1 (set to 24.6V)
Stereo 8Ω: 19W x 2 (set to 12.3 V / ch.) Stereo 2Ω: 75W x 2 (set to 12.3 V / ch.) Bridged 16Ω: 38W x 1 (set to 21.2V) Bridged 3Ω: 150W x 1 (set to 21.2V)
Stereo 8Ω: 14W x 2 (set to 10.6 V / ch.) Stereo 1.5Ω: 75W x 2 (set to 10.6 V / ch.) Bridged 12Ω: 100W x 1 (set to 34.6V) Bridged 12Ω: 100W x 1 (set to 34.6V)
Stereo 6Ω: 50W x 2 (set to 17.3 V / ch.) Stereo 4Ω: 75W x 2 (set to 17.3 V / ch.) Bridged 12Ω: 100W x 1 (set to 34.6V) Bridged 8Ω: 150W x 1 (set to 34.6V)
Stereo 6Ω: 38W x 2 (set to 15.0 V / ch.) Stereo 3Ω: 75W x 2 (set to 15.0 V / ch.) Bridged 12Ω: 100W x 1 (set to 30.0V) Bridged 6Ω: 150W x 1 (set to 30.0V)
Stereo 6Ω: 25W x 2 (set to 12.3 V / ch.) Stereo 2Ω: 75W x 2 (set to 12.3 V / ch.) Bridged 12Ω: 100W x 1 (set to 24.6V) Bridged 4Ω: 150W x 1 (set to 24.6V)
Stereo 6Ω: 19W x 2 (set to 10.6 V / ch.) Stereo 1.5Ω: 75W x 2 (set to 10.6 V / ch.) Bridged 12Ω: 100W x 1 (set to 21.2V) Bridged 3Ω: 150W x 1 (set to 21.2V)
Stereo 4Ω: 50W x 2 (set to 15.0 V / ch.) Stereo 3Ω: 75W x 2 (set to 15.0 V / ch.) Bridged 8Ω: 100W x 1 (set to 30.0V) Bridged 6Ω: 150W x 1 (set to 30.0V)
Stereo 4Ω: 38W x 2 (set to 12.3 V / ch.) Stereo 2Ω: 75W x 2 (set to 12.3 V / ch.) Bridged 8Ω: 50W x 1 (set to 24.6V) Bridged 4Ω: 150W x 1 (set to 24.6V)
Stereo 4Ω: 28W x 2 (set to 10.6 V / ch.) Stereo 1.5Ω: 75W x 2 (set to 10.6 V / ch.) Bridged 8Ω: 50W x 1 (set to 21.2V) Bridged 3Ω: 150W x 1 (set to 21.2V)
Stereo 3Ω: 50W x 2 (set to 12.3 V / ch.) Stereo 2Ω: 75W x 2 (set to 12.3 V / ch.) Bridged 6Ω: 100W x 1 (set to 24.6V) Bridged 4Ω: 150W x 1 (set to 24.6V)
Stereo 3Ω: 38W x 2 (set to 10.6 V / ch.) Stereo 1.5Ω: 75W x 2 (set to 10.6 V / ch.) Bridged 6Ω: 100W x 1 (set to 21.2V) Bridged 3Ω: 150W x 1 (set to 21.2V)
Stereo 2Ω: 56W x 2 (set to 10.6 V / ch.) Stereo 1.5Ω: 75W x 2 (set to 10.6 V / ch.)

16 | JL Audio - 300/4v2 Owner’s Manual 17

Appendix D: 
Precise Frequency Selection Chart

“Filter FREQ” Front / REAR Filters

Detent Panel Actual
Number Marking Freq.
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

18 | JL Audio - 300/4v2 Owner’s Manual 19

Appendix E: TROUBLE SHOOTING
“How do I properly set the input sensitivity on my amplifier” “My amplifier shuts off once in a while, usually at higher volumes”
Please r efer to Appendix A (page 14) to set the input sensitivity for Check y our voltage source and grounding point. The power supply
maximum, low-distortion output. of the 300/4v2 will operate with charging system voltages
“My amplifier doesn’t turn on” down to 10V. Shutdown problems at higher volume levels
Check t he fuse, not just visually, but with a continuity meter. It is can occur when the charging system voltage drops below
possible for a fuse to have poor internal connections that 10V. These dips can be of very short duration making them
cannot be found by visual inspection. It is best to take the extremely difficult to detect with a common DC voltmeter.
fuse out of the holder for testing. If no problem is found with To ensure proper voltage, inspect all wiring and termination
the fuse, inspect the fuse-holder. points. It may also be necessary to upgrade the ground
Check t he integrity of the connections made to each of the wire connecting the battery to the vehicle’s chassis and the
“+12VDC”, “Ground”, and “Remote” terminals. Ensure power wire connecting the alternator to the battery. Many
that no wire insulation is pinched by the terminal set screw vehicles employ small (10 AWG - 6 AWG) wire to ground the
and that each connection is tight. battery to the vehicle’s chassis and to connect the alternator to
Check t o make sure there is +12V at the “Remote” connection of the the battery. To prevent voltage drops, these wires should  be
amplifier. In some cases, the turn-on lead from the source unit upgraded to 4 AWG when installing amplifier systems with
is insufficient to turn on multiple devices and the use of a relay main fuse ratings above 60A. Grounding problems are the
is required. To test for this problem, jump the “+12VDC” wire leading cause of misdiagnosed amplifier “failures.”
to the “Remote” terminal to see if the amplifier turns on.
“My amplifier turns on, but there is no output”
“I get a distorted / attenuated sound coming out of the speaker(s)” Check t he input signal using an AC voltmeter to measure the
Check t he speaker wires for a possible short, either between the voltage from the source unit while an appropriate test tone is
positive and negative leads or between either speaker lead played through the source unit (disconnect the input cables
and the vehicle’s chassis ground. If a short is present, you from the amplifier prior to this test). The frequency used
will experience distorted and/or attenuated output. The should be in the range that is to be amplified by the amplifier
“Low Ω” light will illuminate in this situation. It may be (example: 50 Hz for a sub bass application or 1 kHz for a full
helpful to disconnect the speaker wires from the amplifier range / high-pass application). A steady, sufficient voltage
and use a different set of wires connected to a test speaker. (between 200mV and 8.0-volts) should be present at the
Check t he nominal load impedance to verify that each channel output of the signal cables.
of the amplifier is driving a load equal to or greater than Check t he output of the amplifier. Using the procedure explained in
1.5 ohms in stereo mode (3 ohms bridged). the previous check item (after plugging the input cables back
Check t he input signal and input signal cables to make sure signal into the amplifier) test for output at the speaker outputs of
is present at the “Amplifier Inputs” and the cables are not the amplifier. Unless you enjoy test tones at high levels, it is
pinched or loose. It may be helpful to try a different set of a good idea to remove the speaker wires from the amplifier
cables and/or a different signal source to be sure. while doing this. Turn the volume up approximately half
way. 5V or more should be measured at the speaker outputs.
“My amplifier’s output fluctuates when I tap on it or hit a bump” This output level can vary greatly between amplifiers but it
Check t he connections to the amplifier. Make sure that the should not be in the millivolt range with the source unit at
insulation for all wires has been stripped back far enough to half volume. If you are reading sufficient voltage, check your
allow a good contact area inside the terminal block. speaker connections as explained below.
Check t he input connectors to ensure that they all are making good Check to ensure that the speaker wires are making a good
contact with the input jacks on the amplifier. connection with the metal inside the terminal block. The
speaker wire connectors are designed to accept up to 8 AWG
wire. Make sure to strip the wire to allow for a sufficient
connection with the metal inside the terminal block.

20 | JL Audio - 300/4v2 Owner’s Manual 21

INSTALLATION NOTES:
Use this diagram to document your amplifier’s switch and control positions.

+12VDC Ground Remote Rear Filter Controls Rear Input Section Rear Speaker Outputs Front Filter Controls Front Input Section Front Speaker Outputs
Freq. Range Filter Slope Input Voltage Input Sens. Freq. Range Filter Slope Input Voltage Input Sens. Input Mode

x1 | x10 12dB | 24dB Low | High x1 | x10 12dB | 24dB Low | High 2ch | 4ch
95 95
75 130 Filter Mode 75 130 Filter Mode

300 /4v2 60 200

Left Right
60 200
Left Right
Four-Channel Full-Range Amplifier 50 500 Off | LP | HP 50 500 Off | LP | HP

Filter Freq. (Hz) Left Ch. Right Ch. Bridged Filter Freq. (Hz) Left Ch. Right Ch. Bridged

22 | JL Audio - 300/4v2 Owner’s Manual 23

Limited Warranty - 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 product’s 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
9:00 AM – 5:30 PM (Eastern Time Zone)
JL Audio, Inc
10369 North Commerce Pkwy.
Miramar, FL 33025
(do not send product for repair to this address)

International Warranties:
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 A/B 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.

Printed in China 300/4v2MAN-CH-03-2007