JL Audio M-Series M1400 Owner's Manual

Thank you for purchasing a JL Audio amplif ier for

your marine sound system.

Your amplifier has been designed and manufactured to exacting

standards in order to ensure years of musical enjoyment in your vessel.

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 [phone] during business hours.

OWNER’S MANUAL

M140 0

monoblock marine subwoofer amplifier

PLANNING YOUR INSTALLATION

It is important that you take the time to read
this manual and t hat you plan out your
installation carefully. The followi ng are some
considerations that you must take into account
when planning your installation.

Cooling Ef ficiency Consi derations:

The outer shell of your JL Audio amplifier
is designed to remove heat from the amplifier
circuit ry. For optimum cooling per formance,
this outer shell should be exposed to as large a
volume of air as possible. Enclosing the a mplifier
in a smal l, poorly ventilated cha mber can
lead to excessive heat build-up and degraded
performance. If an installation calls for an
enclosure around the amplifier, we recommend
that this enclosure be ventilated with the aid
of a fan. In normal applications, fan-cooling
is not necessa ry.

Mounting the amplifier upside down is
strongly discouraged.

If mounting the ampli fier under a seat,
make sure t here is at least 1 inch (2.5 cm) of
space above the amplif ier’s outer shell to per mit
proper cooling.

Safety Considerations:

Your amplifier needs to be installed in a dry,
well-ventilated envi ronment and in a manner
which does not i nterfere wit h your vessel’s factory
insta lled electronic dev ices. You should also take
the time to s ecurely mount the ampli fier using the
supplied screws so that it does not come loose in
the event of a col lision or a sudden jolt to the vessel.

Stupid Mistakes to Avoid:

• Check before drilli ng any holes in your vessel to

make sure that you will not be drilling through
the hull, a fuel tank, fuel line, wiring harness or
other vital vessel system.

• Do not run system wir ing outside or underneath

the vessel. This is an extremely dangerous
practice which can result in severe damage to
your vessel a nd person.

• Protect all system wires from sharp ed ges

(metal, fiberglass, etc.) by careful ly routing
them, ty ing them down and using grommets
and loom where appropriate.

• Do not mount the amplifier in the engine

compart ment or in any other area that w ill
expose t he amplifier circuitry to the elements.

While this amplif ier is specially desig ned
for marine applications, it is not waterproof
and it should not be mou nted where it is
likely to get wet.

JL AUDIO M1400 3

PROTECT YOUR HEARING!

We value you as a long-term customer. For
that reason, we urge you to pract ice restraint in
the operation of this product so as not to damage
your hearing and that of others in your vessel.
Studies have shown that continuous exposure to
high sound pressure levels can lead to permanent
(irreparable) hearing loss. This and a ll other
high-power ampli fiers are capable of producing
such high sound pressure levels when connected
to a speaker system. Please lim it your continuous
exposure to high volume levels.

While driving, operate your aud io system in
a manner that stil l allows you to he ar necessary
noises to operate your vessel safely (horns,
sirens, etc.).

SERIAL NUMBER

In the event that your amplifier requi res
service or is ever stolen, you will need to have
a record of the product’s serial number. Please
take the time to enter that number in the space
provided below. The serial number can be fou nd
on the bottom panel of the amplifier and on the
amplifier packaging.

Serial Number:

INSTALLATION APPLICATIONS

This ampl ifier is designed for oper ation in
vessels w ith 12 volt, negative-ground electr ical
systems. Use of this product in vessels with
positive ground and/or voltages other than 12V
may result in damage to the product and will void
the warranty.

This product is not certified or approved for
use in aircraft.

Do not attempt to “ bridge” the outputs of this
amplif ier with the outputs of a second amplif ier,
including an identical one.

2 JL AUDIO M1400

Bass Boost Controls

Input Voltage

Low | High

CH 1 (Left)

Input Sens. LP Filter

Filter Freq. (Hz)

40

45

55

65

80

100

200

Bass Boost

Remote

Bass Port

Power Prote ct

CH 2 (Right)

Pre-Outs

Left & Right

Preamp Input Jacks

(pg. 6)

Protection Status

Indicator

(pg. 9)

Left & Right

Preamp Output Jacks

(pg. 8)

Input Voltage

Selection

(pg. 6)

Power Status

Indicator

(pg. 9)

Bass EQ

On/Off Switch

(pg. 8)

Jack for

Remote Bass

Control Knob

(pg. 8)

Filter Mode

Selection

(pg. 7)

Filter

Frequency Selector

(pg. 7)

Input Sensitivity

Control

(pg. 6)

Remote Turn-On

Connector

(pg. 6)

Chassis Ground

Connector

(pg. 5)

+12 V Power

Connector

(pg. 5)

Speaker Outputs

(pg. 8)

POWER CONNECTIONS

Before installing the amplifier, disconnect the
negative (ground) wire from the vessel’s battery.
This will prevent ac cidental damage to t he system,
the vessel and your body du ring instal lation.

The M1400’s “+12 V DC” and “Ground”
connect ions are designed to accept 4 AWG power
wire. 4 AWG is a minimum power wire size for
this amplifier.

If you are install ing the M1400 w ith other
amplif iers and wish to use a single main power
wire, use 4 AWG or larger main power wi re
(depending on the overall current demands of all
the ampli fiers in the system). This 4 AWG or
larger power w ire should terminate i nto a
distribution block mounted as close to t he
amplif iers as possible a nd should connec t to the
M1400 with 4 AWG power wire.

Note: Smaller AWG numbers mea n bigger wire
and vice-versa (1/0 AWG is the largest, 2 AWG is
smaller, then 4 AWG, then 8 AWG, etc.).

To connect the power wires to the a mplifier,
first back out the set screw on the top of t he
termina l block, using the supplied 2 .5 mm hex
wrench. St rip 1/2 inch (12 mm) of insu lation from
the end of each w ire and insert the bare wire i nto
the termi nal block, seating it f irmly so that no
bare wire is exposed . While holding the wi re in
place, tig hten the set screw firmly, taki ng care not
to strip the head of the screw.

The ground connection should be made using

the same gau ge wire as t he power connection.

Any wires run th rough bar riers must be
protected with a high quality rubber grom met
to prevent damage to the insulation of the wire.
Failure to do so may result in a d angerous short
circuit.

Many vessels employ small (10 AWG - 6 AWG)
wire to connect the alternator’s positive
connection to the batter y. To prevent voltage
drops, this wire should be upgraded to 4 AWG
when installing amplif ier systems with main
fuse ratings above 60A.

It is common for the alternator to be grounded
through its chassis. If the a lternator is not
grounded t hrough its chassis a nd instead employs
a small (10 AWG - 6 AWG) wire to con nect to
ground, this wire should also be upgraded to 4
AWG when insta lling amplif ier systems with main
fuse rat ings above 60A.

FUSE REQUIREM ENTS

It is absolutely vital that the main power
wire(s) to the ampli fier(s) in the system be
fused w ithin 18 inches (45 cm) of the positive
battery post connection. The fuse va lue at each
power wire shou ld be high enough for all of the
equipment being run from t hat power wire. If
only the M1400 is being ru n from that power
wire, we recommend a 40A fuse be used. ANL
(big blade fuse), AFS (small blade fuse), AGU (big
glass fuse) or MaxiFuse™ (big plastic-body fuse)
types are recommended.

No fuse is required or recommended direct ly
before the ampl ifier power connection. If one is
desired, we recommend the u se of a 40A AGU,
AFS or MaxiFuse™ type.

JL AUDIO M1400 5

PRODUCT DE SCRIPTION

The JL Audio M1400 is a monoblock
subwoofer ampli fier utilizi ng proprieta ry and
patented Class D technolog y. Its frequency
response is limited to t he range below 250 Hz. It
is not designed for drivi ng midrange speakers or
tweeters . Every aspect of its operation has been
optimized for low-frequency amplif ication.
For detailed specif ications, please refer to
Appendix C (page 13).

TYPICAL I NSTALLATION SEQUE NCE

The followi ng represents the sequence for a
typical ampli fier installation, using an af termarket
source unit. Additional steps a nd different
procedures may be required in some applications.
If you have any quest ions, please contact your
authoriz ed JL Audio dealer for assist ance.

1) Disconnect the negative battery post

connection and secure the disconnected c able
to prevent accidental re-connection dur ing
installation. This step is not optional!

2) Run positive a nd negative power w ire

(minimum 4 AWG) from from the bat tery
location to the a mplifier mounting location,
taki ng care to route it i n such a way that it
will not be damaged and wil l not interfere
with vessel operation. Use 4 AWG or larger
power wire and a power dist ribution block
if additional ampli fiers are being installed
with the M1400.

3) Connect power wire to the positive bat tery

post. Fuse t he wire w ith 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 vessel.
Do not insta ll the f use unt il the power wire
has been connected to the amplif ier.

4) Connect negat ive power wire to the negative

battery post. Use the same siz e power
wire as t he wire connected to t he “+12V ”
connection (minimum 4 AWG).

5) Run signa l cables and remote turn-on w ire

from the source unit to the amplif ier
mounting location.

6) Run speaker wire from t he speaker system

to the ampli fier mount ing location.

7) Securely mount t he amplif ier using the

supplied screws.

8) Connect the positive and negative power

wires to the amplif ier. A fuse near the
amplif ier is not necessary.

9) Connect the remote turn-on wire to

the amplifier.

10) Connec t the input cables to the amplifier.

11) Con nect the speaker w ires to the amplif ier.

12) Careful ly review the ampli fier’s control

settings to make sure that they are set
according to the needs of t he system.

13) Install power wire f use (40A for a single

M1400) and reconnec t the negative
battery post terminal.

14) Turn on the source u nit 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 set tings.

15) Make necessa ry adjust ments to the i nput

sensitiv ity controls to obtai n the rig ht
overall out put and the desired balance in t he
system. See Appendix A (page 12)
for the recommended input sensit ivity
setti ng method.

16) Enjoy the f ruits of your labor wit h your

favorite music.

4 JL AUDIO M1400

AMPLIFIER CONTROLS

1) “I nput Se ns.”: Once the appropriate “Input
Vol ta ge ” range has been selected , the control
labeled “Input Sens.” located in the “Amplifier
Controls” section ca n be used to match the

source unit’s output voltage to the input
stage of the a mplifier for maxi mum clean
output. Rotating the cont rol clockw ise will
result in higher sensit ivity (louder for a given
input voltage). Rotating the control counter­clockwise will result i n lower sensitiv ity
(quieter for a given input voltage.)

Input Sens. LP Filter

Filter Freq. (Hz)

40

45

55

65

80

100

200

To properly set the ampli fier for maximum
clean output, please refer to Appendix A (page

12

) in this manual. After u sing this procedure ,

you can then adjust any or all “Input Sens.”
levels downward if this is required to achieve
the desired system ba lance.

Do not increase any “Input Sens.” setting

for any channe l(s) of any a mplifier in the
system beyond t he maximum level est ablished
during t he procedure outlined i n Appendix
A (page 12). Doing so will result in audible
distortion a nd possible speaker damage.

Filter Controls

Most speakers are not designed to reproduce
the full range of frequencies audible by the
human ear. For this reason, most speaker
systems are comprised of mu ltiple speakers, each
dedicated to reproducing a specific f requency
range. Filters are used to select which frequency
range is sent to each section of a speaker system .
The division of frequency ra nges to different
speakers can be done with passive filters (coils
and/or capacitors between the amplifier outputs
and the speakers), which a re acceptable and
commonly us ed for filtering between mid­range speakers and tweeters . Filteri ng between
subwoofer systems and satellite spe aker systems
is best done with active filters, which cut off
frequency c ontent at the input to t he amplifier.
Active filters are more s table tha n passive filters
and do not introduce extra neous resistance,
which can degrade subwoofer performance.

The active filter bu ilt into the M1400 can be
used to eli minate potential ly harmful a nd/or
undesired f requencies from making their way
through the amplifier sections to the speaker(s).
This ser ves to improve tonal bala nce and to avoid
distort ion and possible speaker failure . Correct
use of these filters can substantially increase t he
longevity a nd fidelity of your audio s ystem.

The M1400 employs a sophisticated , variable,
low-pass active f ilter for its internal channel.
This featu re is designed to attenuate frequencie s
above its filter frequency, so that the system’s
subwoofers do not reproduce a ny audible
midrange content.

2) Filte r Operation : The low-pass filter in the

M1400 is ful ly variable between 4 0 Hz and
200 Hz via the “Filter Freq.” control k nob
and features the abil ity to select between a
moderate “12dB” per octave or a steep “24dB”
per octave slope via the “Mode/Slope” switch.
Depending on the subwoofer s ystem and
the vehicle, different slopes may be requi red
to produce a smooth transition to the mid­bass spea kers in the system. E xperiment to
find the slope which best matches the acoustic
requirements of your system.

JL AUDIO M1400 7

TURNON LE AD

The M1400 uses a conventional +12V remote
turn-on lead, ty pically controlled by the source
unit's remote turn-on output. T he amplif ier 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 dedic ated remote
turn-on out put, the amplifier’s turn-on lead ca n
be connected to +12V via a switch that derives
power from an ignition-switched circuit.

The M1400’s “Remote” turn-on connector is
designed to accept 18 AWG – 12 AWG wire . To
connect the remote turn-on wire to the amplif ier,
first back out the set screw on the top of t he
termina l block, using the supplied 2 .5 mm hex
wrench. Strip 1/2 inch (12mm) of wire and inser t
the bare wire into the termina l block, seating it
firmly so that no bare wire is exposed. While
holding the w ire in the terminal, tighten the set
screw firmly, tak ing care not to strip the head of
the screw and maki ng sure that the wire is f irmly
gripped by t he set screw.

INPUT SECTION

The M1400’s input section allows you to send
signal to t he amplifier section through the use
of two dif ferential-balanc ed inputs, one for t he
left channel signa l and one for the right channel
signal. Connection is via RCA-type jacks.

Input Voltage

Low | High

CH 1 (Left)

CH 2 (Right)

You may run a stereo or a mono signal into
the inputs of t he amplif ier. The amplifier’s input
section automatical ly sums stereo signal s to mono
for the internal ampli fier section. The a mplifier
will operate wit h only one input connection (left
or right), but will require an increase in input
sensitiv ity to overcome the loss of signa l. If a
mono input signal is to be run, we recommend
that you use a “Y-adaptor” to split the mono
signal into both inputs of the amplifier.

INPUT VOLTAGE RANGE:

A wide range of signal i nput voltages ca n be
accommodated by the M1400’s input section
(200mV – 8V). This wide ra nge is split up into
two sub-ranges, accessible via a sw itch located to
the left of the Input Connectors.

The “Low” position on the “Input Voltage”
switch selects an input sensitiv ity range between
200mV and 2V. This means that the “Input
Sens.” rotary control will oper ate with in that
voltage window. If you are using a sou rce unit
with convent ional preamp-level outputs , this is
most likely the position that you wi ll use.

The “High” position on the “Input Voltage”
switch selects an input sensitiv ity range between
800mV and 8V. This is usef ul for certain high­output preamp level signals as well as speaker­level outputs from source units not equipped w ith
preamp-level out puts.

To use speaker-level sources, splice the speaker
output wires of the source u nit or smal l amplifier
onto a pair of RCA plugs. No line output
converter is needed in most cases.

The output of the ampl ifier will decre ase for
a given input volta ge when the “Input Range”
switch is placed in the “High” position.
Conversely, the output will be higher with the
switch in t he “Low” position. Wh ile this may
sound counter-intuitive, it is consistent with the
descriptions above.

6 JL AUDIO M1400