ENGLISH
ESPAÑOL
FRANCAIS
DEUTSCH
FL+
White
Blanco
Blanc
Weiß
FL–
White/Black
Blanco/Negro
Blanc/Noir
Weiß/Schwarz
FR+
Gray
Gris
Gris
Grau
FR–
Gray/Black
Gris/Negro
Gris/Noir
Grau/Schwarz
RL+
Green
Verde
Vert
Grün
RL–
Green/Black
Verde/Negro
Vert/Noir
Grün/Schwarz
RR+
Purple
Púrpura
Violet
Lila
RR–
Purple/Black
Púrpura/Negro
Violet/Noir
Lila/Schwarz
Problem
Possible Cause
Solution
How to properly set
input sensitivity
Please refer to Appendix A to set the
input sensitivity for maximum, low-
distortion output.
Amplifier doesn’t
turn on
Faulty fuse
Remove fuse and check with continuity
meter. Replace if necessary.
Poor connection
integrity
Check “+12V”, “Ground”, and “Remote”
leads for pinched wires; ensure tight
connections.
Insufficient “Remote”
input
Make sure there is a suff12V
supply at the “Remote” connection; if
not a relay may be required.
Intermittent output,
fluctuates when I tap
on it or hit a bump
Poor connection
integrity
Make sure insulation has been properly
stripped back at connection points for
good contact area.
Make sure input connectors are making
good contact with input jacks of the
amplifier.
Distorted, attenuated,
or popping sound
Faulty speaker
connection (Short
Circuit / Over Current
Protection)
Inspect speaker wires for possible
short-circuit, either together or shorted
to the vehicle’s chassis ground.
Check the nominal load impedance at
the amplifier is equal to or greater than
2 ohms stereo (4 ohms bridged).
Output shuts off after
a while
Overheating
condition (Thermal
Protection)
Make sure amplifier mounting area has
adequate space for ventilation and heat
dissipation.
Limited Warranty – Amplifiers (USA)
JL Audio warrants this product to be free of defects in materials and
workmanship for a period of two (2) years from the original date of purchase.
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.
Do not increase any “Input Sens.” setting for any amplifier channel or
channel pair 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.
HX280/4 and MHX280/4
Nom. Impedance
Target AC Voltage
4Ω
14.1 V
2Ω
11.8 V
Bridged to 4Ω
23.7 V
Rear
[REAR IN]
[FRONT IN]
White
White/Black
Gray
Gray/Black
Green
Green/Black
Purple
Purple/Black
Source
(Not Used)
[FR–]
[FR+]
[RL–]
[RL+]
[RR–]
[RR+]
[FL–]
[FL+]
White
White/Black
Gray
Gray/Black
Green
Green/Black
Purple
Purple/Black
Front
Amplifier Inputs
Speaker Outputs
4 Stereo Outputs (non-fading)
Channel Mode:
2CH
Inputs:
Use Front Inputs Only
RMS Power:
50W x 4 @ 4 Ω (70W x 4 @ 2 Ω)
Rear
[REAR IN]
[FRONT IN]
White
White/Black
Gray
Gray/Black
Green
Green/Black
Purple
Purple/Black
Source
[FR–]
[FR+]
[RL–]
[RL+]
[RR–]
[RR+]
[FL–]
[FL+]
White
White/Black
Gray
Gray/Black
Green
Green/Black
Purple
Purple/Black
Front
Amplifier Inputs
Speaker Outputs
4 Stereo Outputs (fading)
Channel Mode:
4CH
Inputs:
Use Front and Rear Inputs
RMS Power:
50W x 4 @ 4 Ω (70W x 4 @ 2 Ω)
Rear
[REAR IN]
[FRONT IN]
White
White/Black
Gray
Gray/Black
Green
Green/Black
Purple
Purple/Black
Source
(Not Used)
[FR–]
[FR+]
[RL–]
[RL+]
[RR–]
[RR+]
[FL–]
[FL+]
White
White/Black
Gray
Gray/Black
Green
Green/Black
Purple
Purple/Black
Front
Amplifier Inputs
Speaker Outputs
2 Bridged Mono Outputs
Channel Mode:
2CH
Inputs:
Use Front Inputs Only
RMS Power:
140W x 2 @ 4 Ω
[REAR IN]
[FRONT IN]
Source
Front
White
White/Black
Gray
Gray/Black
Green
Green/Black
Purple
Purple/Black
[FR–]
[FR+]
[RL–]
[RL+]
[RR–]
[RR+]
[FL–]
[FL+]
White
Y-Adaptor
Y-Adaptor
White/Black
Gray
Gray/Black
Green
Green/Black
Purple
Purple/Black
Amplifier Inputs
Speaker Outputs
2 Bridged Stereo Outputs
Channel Mode:
4CH
Inputs:
Left Signal to Both Front Inputs / Right
Signal to Both Rear Inputs
RMS Power:
140W x 2 @ 4 Ω
Rear
[REAR IN]
[FRONT IN]
Source
(Not Used)
Front
White
White/Black
Gray
Gray/Black
[FR–]
[FR+]
[FL–]
[FL+]
White
White/Black
Gray
Gray/Black
Green
Green/Black
Purple
Purple/Black
[RL–]
[RL+]
[RR–]
[RR+]
Green
Green/Black
Purple
Purple/Black
2 Stereo Front + 1 Bridged Mono Rear
Output
Channel Mode:
3CH
Inputs:
Use Front Inputs Only
RMS Power:
50W x 2 @ 4 Ω (70W x 2 @ 2 Ω) + 140W
x 1 @ 4 Ω
Amplifier Inputs
Speaker Outputs
Amplifier Inputs
Speaker Outputs
2 Stereo Front + 2 Mono Rear Outputs
Channel Mode:
3CH
Inputs:
Use Front Inputs Only
RMS Power:
50W x 4 @ 4 Ω (70W x 4 @ 2 Ω)
Rear
[REAR IN]
[FRONT IN]
Source
(Not Used)
Front
White
White/Black
Gray
Gray/Black
Green
Green/Black
Purple
Purple/Black
White
White/Black
Gray
Gray/Black
Green
Green/Black
Purple
Purple/Black
[FR–]
[FR+]
[FL–]
[FL+]
[RL–]
[RL+]
[RR–]
[RR+]
Troubleshooting
Appendix A:
Input Sensitivity Level Setting
Following the directions below will allow the installer to adjust the input
sensitivity of each amplifier channel pair in just a few minutes using equipment
commonly available in installation bays.
Necessary Equipment
• Digital AC Voltmeter
• CD or file 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.).
The Nine-Step Procedure
1)
Disconnect the speakers from the amplifier’s speaker output connec-
tors (you need only disconnect one wire on each output).
2)
Turn off all processing (bass/treble, loudness, EQ, etc.) on the source
unit, processors (if used) and amplifier. Set the source unit’s fader con-
trol to center position and its subwoofer level control to 3/4 of maxi-
mum.
3)
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 rea-
sonable gain overlap with moderate clipping at full volume.
5)
Using the chart on this page, determine the target voltage for input
sensitivity adjustment according to the nominal impedance of the
speaker system connected to the amplifier outputs.
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) at 3/4 source unit volume.
7)
Connect the AC voltmeter to the speaker output connectors of the
amplifier. Make sure you test the voltage at the correct connectors
(+ and –).
8)
Increase the “Input Sens.” control until the target voltage is observed
with the voltmeter.
9)
Once you have adjusted the amplifier to its maximum low-distortion
output level, reconnect the speaker(s) and listen to the system. The
“Input Sens.” controls can now be adjusted downward if the amplifier
requires attenuation to achieve the desired system balance.
