Problem Possible Cause Solution
How to properly set
input sensitivity
Please refer t o Appendix A to set the
input sensitivity for maximum, low-
distortion output.
Amplifier doesn ’t
turn on
F aulty fuse
Remove fuse and check with continuity
meter . Replace if necessary.
Poor connection
integrity
Check “+12V” , “ Ground” , and “Remote”
leads for pinched wires; ensur e tight
connections.
Insufficient “Remote”
input
Make sure there is a sufficient +12V
supply at the “Remote” connection; if
not a relay may be r equired.
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
F aulty speaker
connection (Short
Circuit / Over Current
Prot ec tion)
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 great er than:
Ch.1 & 2: 2 ohms stereo
Ch.1 & 2: 4 ohms bridged
Sub Ch.: 2 ohms
Output shuts off after
a while
Overheating
condition ( Thermal
Prot ec tion)
Make sure amplifier mounting area has
adequate space for v entilation and heat
dissipation.
No or low subwoof er
output
Remote Bass
Control (optional)
is connected and
turned down
Adjust RBC-1 or M-RBC-1 accordingly
Limited W arranty – Amplifiers (USA )
JL Audio war rants this pro duc t to be f ree of d efe c ts in materials an d
work manship for a p erio d of t wo (2 ) year s from th e original date of p urchase.
This war rant y is not trans fer rable an d applie s only to the or iginal purchas er
from an auth orize d JL Audio de aler. Should ser vi ce be necess ar y und er this
warrant y f or any reason due to manu fac turin g defe c t or malf unc tion, J L
Audio will (at its discretio n) , repair o r replace the d efe c tive produc t w ith new
or remanuf ac ture d produc t at n o charge. Damage c ause d by the follow ing is
not covered unde r warrant y : accident, m isuse, abuse, pro duc t mo dif icatio n or
negl ec t, f ailure to follow ins tallation ins truc ti ons, unautho rize d repair at tempt s,
misreprese ntations by the s eller. This warrant y d oes not cover incid ental or
conseque ntial damages an d does n ot cover the cost of removin g or reins talling
the unit(s ). Cosmetic damage du e to accident or no rmal wear and tear is n ot
covered under warrant y .
Warrant y is voi d if t he p ro duc t ’s seri al num be r has b ee n re moved or d ef ace d.
Any applicab le implie d warr anties are limite d in duration to the p erio d of the
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Do not increase any “Input Sens. ” setting for an y amplifier channel or
channel pair in the system bey ond 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 pr ocedure. This
applies to any EQ boost circuit, including source unit t one controls or EQ circuits. EQ
cuts will not require re-adjustment.
T arget A C V oltage - MX600/3
Nom.
Impedance
Ch.1 & 2
(Stereo)
Ch.1 & 2
(Bridged)
4Ω 17.3 28.3
2Ω 14.1 not recommended
Nom.
Impedance
Ch.3/Subwoof er
4Ω 31.6
3Ω 30.0
2Ω 28.3
T roubleshooting
Appendix A:
Input Sensitivity Level Setting
F ollowing 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 ba ys.
Necessary Equipment
• Digital AC V oltmeter
• CD or file with a sine -wave t est tone recorded at 0 dB r eference level in the
frequency range to be amplified for that set of channels (50 Hz for sub woofer
channels, 1 kHz for a midrange application). Do not use att enuated test tones
(-10 dB, -20 dB, et c.).
The Nine-Step Procedure
1) Disconnect the speakers from the amplifier’ s speaker output
connectors (you need only disconnect one speaker wire).
2) T urn off all processing (bass/treble , loudness, EQ , etc.) on the source
unit, processors (if used) and amplifier . S et the source unit’ s fader
control to c enter position and its subwoofer lev el control to
3/4 of maximum.
3) Set both “Input V oltage” switches to “Low” and tur n both “Input
Sens. ” controls all the way down.
4) Set the source unit volume to 3/4 of full v olume. This will allow for
reasonable gain overlap with moder ate clipping at full volume.
5) Using the T arget A C Voltage chart (at right), determine the target
voltage for input sensitivity adjustment acc ording to the nominal
impedance of the speaker system connected to the amplifier outputs .
6) V erify that you have disconnected the speakers befor e proceeding. P lay
a track with an appropriate sine wa ve (within the frequency range to
be amplified) at 3/4 source unit v olume.
7) Connect the AC voltmet er to the speaker output connectors of the
amplifier . Make sure you test the v oltage at the correct connectors
(+ and –).
8) Increase the “Input S ens. ” contr ol until the target voltage is observed
with the voltmeter . Not e: If excessive voltage is measured with the
control set at minimum (full c ounterclockwise), change the “I nput
V oltage” switch setting to “High” and re-adjust.
9) Once you hav e adjusted the amplifier to its maximum low-distortion
output level, r econnect the speaker(s) and listen to the system. The
“Input Sens. ” controls can now be adjusted down ward if the amplifier
requires att enuation to achieve the desired system balanc e.
Specications MX600/3
Rated RMS Pow er @
14.4V , <1% THD+N
Main @
4 Ω
Main @
2 Ω
Main @ 4 Ω
Bridged
Sub @
4 Ω
Sub @
3 Ω
Sub @
2 Ω
75 W x 2 100 W x 2 200 W x 1 250 W x 1 300 W x 1 400 W x 1
Rated RMS Pow er @
12.5V , <1% THD+N
Main @
4 Ω
Main @
2 Ω
Main @ 4 Ω
Bridged
Sub @
4 Ω
Sub @
3 Ω
Sub @
2 Ω
50 W x 2 80 W x 2 160 W x 1 200 W x 1 250 W x 1 300 W x 1
Fr equenc y Response 20 Hz - 20 kHz (+0, -1dB), 6.3 H z - 30 kHz (+0, -3dB)
S/N Ratio, A-w eighted,
20 kHz noise
bandwidth
88 dB (Referred to rat ed power), 68 dB (Referred to 1 W )
Damping F actor >92 / 50 Hz @ 4 Ω, >43 / 50 H z @ 2 Ω
Input Voltage Range 250 mV - 4 V (Lo w) or 580 mV - 14 V (High)
Input Mode Switch 2 / 4 Channel
Fr ont High-Pass Filt er Freq . Range: 35 - 300 H z Slope: 12 dB/Octave
Sub Low-P ass Filt er Freq. Range: 40 - 400 Hz Slope: 24 dB/Octave
Infrasonic Filter Freq. Range: 20 - 40 Hz Slope: 12 dB/Octave
Sub Output Polarity 0 or 180 degrees
Bass Boost EQ 0 to +12 dB @ 43 Hz
Remote Bass Controller M-RBC-1 or RBC-1 (sold separately)
Input Operating
V oltage
11 - 15 VDC
Min Power/GND W ire 4 A WG
F use Rating 60A
Dimensions 9.33 in x 4.50 in x 1.77 in / 237 mm x 114.5 mm x 45 mm
Status LED’ s / Protection Circuitry
There are tw o status indicator lights on the wiring end panel of the amplifier .
1. “POWER ” (Green): Lights to indicat e that the amplifier is turned on and
operating normally .
2. “PROTECT ” (Red): Lights to indicate the amplifier’ s protection circuitry
has been triggered to prev ent product failure due to any conditions
noted in the chart below . When a pr otection mode is ac tivated, the
amplifier will shut down to prot ec t its circuitry. F or Thermal Pr otection,
Over Current and Short Circuit conditions, the amplifier will r esume
normal operation once the problem is corr ected, with the “Protect” LED
turning off . For Over V oltage conditions, the amplifier must be turned
off/on to return to normal operation. Not e: connecting the speaker
outputs to impedances low er than 2 ohms (4 ohms bridged) will also
cause this protection mode to activate.
POWER
(Green LED )
PROTECT
(Red LED)
Status/Condition Note
ON OFF Normal Operation
OFF ON Thermal Prot ec tion Lasts until temp cools to normal
OFF/ON ON/OFF Over Current Green/Red LEDs alternate for 1 second
OFF ON Short Circuit Possible audible “popping ” noise
OFF ON Over V oltage T urn amp off/on to restart
Appendix B
Remote Bass Contr ol
With the optional RBC-1 or M-RBC-1 Remote Bass Contr ol (each sold separately),
you can contr ol the subwoofer volume fr om the front of the vehicle/vessel .
The remote ’ s plug connec ts to the amplifier’ s harness-mounted RJ11 input
jack. When c onnected to the amplifier , the Remote Bass Control opera tes as
follows . At full counter-clockwise rotation, the audio will mute completely . At full
clockwise rotation the level will be the same as if the remote w as not connected
at all. In other words , it operates strictly as a subwoofer level a ttenuator . This
control will not aff ect the “Bass Boost” feature of the amplifier . Care should
be taken to securely mount this con trol in a manner that does not interfere
with vehicle/vessel opera tion. When setting the amplifier’ s input sensitivity ,
the Remote Bass Control should be unplugged or a t full clockwise rotation
(maximum level).