JL Audio M1700 User manual

Thank you for purchasing a JL Audio amplifier 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 vehicle.
For maximum performance, 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

PROTECT YOUR HEARING!
We value you as a long-term customer. For
that reason, we urge you to practice 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 all other
high-power amplifiers are capable of producing
such high sound pressure levels when connected
to a speaker system. Please limit your continuous
exposure to high volume levels.
While driving, operate your audio system in
a manner that still allows you to hear necessary
noises to operate your vessel safely (horns,
sirens, etc.).
SERIAL NUMBER
In the event that your amplifier requires
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 found
on the bottom panel of the amplifier and on the
amplifier packaging.
Serial Number:
INSTALLATION APPLICATIONS
This amplifier is designed for operation in
vessels with 12 volt, negative-ground electrical
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
amplifier with the outputs of a second amplifier,
including an identical one.
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
PowerProtect
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)
2 JL AUDIO M1700

PLANNING YOUR INSTALLATION
It is important that you take the time to read
this manual and that you plan out your
installation carefully. The following are some
considerations that you must take into account
when planning your installation.
Cooling Efficiency Considerations:
The outer shell of your JL Audio amplifier
is designed to remove heat from the amplifier
circuitry. For optimum cooling performance,
this outer shell should be exposed to as large a
volume of air as possible. Enclosing the amplifier
in a small, poorly ventilated chamber 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 necessary.
Mounting the amplifier upside down is
strongly discouraged.
If mounting the amplifier under a seat,
make sure there is at least 1 inch (2.5 cm) of
space above the amplifier’s outer shell to permit
proper cooling.
Safety Considerations:
Your amplifier needs to be installed in a dry,
well-ventilated environment and in a manner
which does not interfere with your vessel’s factory
installed electronic devices. You should also take
the time to securely mount the amplifier so that it
does not come loose in the event of a collision or a
sudden jolt to the vessel.
Stupid Mistakes to Avoid:
• Check before drilling 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 wiring outside or underneath
the vessel. This is an extremely dangerous
practice which can result in severe damage to
your vessel and person.
• Protect all system wires from sharp edges
(metal, fiberglass, etc.) by carefully routing
them, tying them down and using grommets
and loom where appropriate.
• Do not mount the amplifier in the engine
compartment or in any other area that will
expose the amplifier circuitry to the elements.
While this amplifier is specially designed
for marine applications, it is not waterproof
and it should not be mounted where it is
likely to get wet.
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
PowerProtect
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)
JL AUDIO M1700 3

PRODUCT DESCRIPTION
The JL Audio M1700 is a monoblock
subwoofer amplifier utilizing proprietary and
patented Class D technology. Its frequency
response is limited to the range below 250 Hz. It
is not designed for driving midrange speakers or
tweeters. Every aspect of its operation has been
optimized for low-frequency amplification.
For detailed specifications, please refer to
Appendix C (page 13).
TYPICAL INSTALLATION SEQUENCE
The following represents the sequence for a
typical amplifier installation, using an aftermarket
source unit. Additional steps and different
procedures may be required in some applications.
If you have any questions, please contact your
authorized JL Audio dealer for assistance.
1) Disconnect the negative battery post
connection and secure the disconnected cable
to prevent accidental re-connection during
installation. This step is not optional!
2) Run positive and negative power wire
(minimum 4 AWG) from from the battery
location to the amplifier mounting location,
taking care to route it in such a way that it
will not be damaged and will not interfere
with vessel operation. Use 4 AWG or larger
power wire and a power distribution block
if additional amplifiers are being installed
with the M1700.
3) Connect power wire to the positive battery
post. Fuse the wire with an appropriate fuse
block (and connectors) within 18 inches (45
cm) wire length of the positive battery post.
This fuse is essential to protect the vessel.
Do not install the fuse until the power wire
has been connected to the amplifier.
4) Connect negative power wire to the negative
battery post. Use the same size power
wire as the wire connected to the “+12V”
connection (minimum 4 AWG).
5) Run signal cables and remote turn-on wire
from the source unit to the amplifier
mounting location.
6) Run speaker wire from the speaker system
to the amplifier mounting location.
7) Securely mount the amplifier.
8) Connect the positive and negative power
wires to the amplifier. A fuse near the
amplifier is not necessary.
9) Connect the remote turn-on wire to
the amplifier.
10) Connect the input cables to the amplifier.
11) Connect the speaker wires to the amplifier.
12) Carefully review the amplifier’s control
settings to make sure that they are set
according to the needs of the system.
13) Install power wire fuse (50A for a single
M1700) and reconnect the negative
battery post terminal.
14) Turn on the source unit at a low level
to double-check that the amplifier is
configured correctly. Resist the temptation
to crank it up until you have verified the
control settings.
15) Make necessary adjustments to the input
sensitivity controls to obtain the right
overall output and the desired balance in the
system. See Appendix A (page 12)
for the recommended input sensitivity
setting method.
16) Enjoy the fruits of your labor with your
favorite music.
4 JL AUDIO M1700

POWER CONNECTIONS
Before installing the amplifier, disconnect the
negative (ground) wire from the vessel’s battery.
This will prevent accidental damage to the system,
the vessel and your body during installation.
The M1700’s “+12 VDC” and “Ground”
connections are designed to accept 4 AWG power
wire. 4 AWG is a minimum power wire size for
this amplifier.
If you are installing the M1700 with other
amplifiers and wish to use a single main power
wire, use 4 AWG or larger main power wire
(depending on the overall current demands of all
the amplifiers in the system). This 4 AWG or
larger power wire should terminate into a
distribution block mounted as close to the
amplifiers as possible and should connect to the
M1700 with 4 AWG power wire.
Note: Smaller AWG numbers mean 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 amplifier,
first back out the set screw on the top of the
terminal block, using the supplied 2.5 mm hex
wrench. Strip 1/2 inch (12 mm) of insulation from
the end of each wire and insert the bare wire into
the terminal block, seating it firmly so that no
bare wire is exposed. While holding the wire in
place, tighten the set screw firmly, taking care not
to strip the head of the screw.
The ground connection should be made using
the same gauge wire as the power connection.
Any wires run through barriers must be
protected with a high quality rubber grommet
to prevent damage to the insulation of the wire.
Failure to do so may result in a dangerous short
circuit.
Many vessels employ small (10 AWG - 6 AWG)
wire to connect the alternator’s positive
connection to the battery. To prevent voltage
drops, this wire should be upgraded to 4 AWG
when installing amplifier systems with main
fuse ratings above 60A.
It is common for the alternator to be grounded
through its chassis. If the alternator is not
grounded through its chassis and instead employs
a small (10 AWG - 6 AWG) wire to connect to
ground, this wire should also be upgraded to 4
AWG when installing amplifier systems with main
fuse ratings above 60A.
FUSE REQUIREMENTS
It is absolutely vital that the main power
wire(s) to the amplifier(s) in the system be
fused within 18 inches (45 cm) of the positive
battery post connection. The fuse value at each
power wire should be high enough for all of the
equipment being run from that power wire. If
only the M1700 is being run from that power
wire, we recommend a 50A fuse be used. AFS
(small blade fuse) or MaxiFuse™ (big plastic-body
fuse) types are recommended.
No fuse is required or recommended directly
before the amplifier power connection. If one is
desired, we recommend the use of a 50A AFS or
MaxiFuse™ type.
JL AUDIO M1700 5

TURNON LEAD
The M1700 uses a conventional +12V remote
turn-on lead, typically controlled by the source
unit's remote turn-on output. The amplifier will
turn on when +12V is present at its “Remote”
input and turn off when +12V is switched off. If
a source unit does not have a dedicated remote
turn-on output, the amplifier’s turn-on lead can
be connected to +12V via a switch that derives
power from an ignition-switched circuit.
The M1700’s “Remote” turn-on connector is
designed to accept 18 AWG – 12 AWG wire. To
connect the remote turn-on wire to the amplifier,
first back out the set screw on the top of the
terminal block, using the supplied 2.5 mm hex
wrench. Strip 1/2 inch (12mm) of wire and insert
the bare wire into the terminal block, seating it
firmly so that no bare wire is exposed. While
holding the wire in the terminal, tighten the set
screw firmly, taking care not to strip the head of
the screw and making sure that the wire is firmly
gripped by the set screw.
INPUT SECTION
The M1700’s input section allows you to send
signal to the amplifier section through the use
of two differential-balanced inputs, one for the
left channel signal and one for the right channel
signal. Connection is via RCA-type jacks.
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
PowerProtect
CH 2 (Right)
Pre-Outs
You may run a stereo or a mono signal into
the inputs of the amplifier. The amplifier’s input
section automatically sums stereo signals to mono
for the internal amplifier section. The amplifier
will operate with only one input connection (left
or right), but will require an increase in input
sensitivity to overcome the loss of signal. 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 input voltages can be
accommodated by the M1700’s input section
(200mV – 8V). This wide range is split up into
two sub-ranges, accessible via a switch located to
the left of the Input Connectors.
The “Low” position on the “Input Voltage”
switch selects an input sensitivity range between
200mV and 2V. This means that the “Input
Sens.” rotary control will operate within that
voltage window. If you are using a source unit
with conventional preamp-level outputs, this is
most likely the position that you will use.
The “High” position on the “Input Voltage”
switch selects an input sensitivity range between
800mV and 8V. This is useful for certain high-
output preamp level signals as well as speaker-
level outputs from source units not equipped with
preamp-level outputs.
To use speaker-level sources, splice the speaker
output wires of the source unit or small amplifier
onto a pair of RCA plugs. No line output
converter is needed in most cases.
The output of the amplifier will decrease for a
given input voltage when the “Input Range”
switch is placed in the “High” position.
Conversely, the output will be higher with the
switch in the “Low” position. While this may
sound counter-intuitive, it is consistent with the
descriptions above.
6 JL AUDIO M1700

AMPLIFIER CONTROLS
1) “Input Sens.”: Once the appropriate “Input
Voltage”range has been selected, the control
labeled “Input Sens.”located in the “Amplifier
Controls”section can be used to match the
source unit’s output voltage to the input
stage of the amplifier for maximum clean
output. Rotating the control clockwise will
result in higher sensitivity (louder for a given
input voltage). Rotating the control counter-
clockwise will result in lower sensitivity
(quieter for a given input voltage.)
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
PowerProtect
CH 2 (Right)
Pre-Outs
To properly set the amplifier for maximum
clean output, please refer to Appendix A (page
12) in this manual. After using this procedure,
you can then adjust any or all “Input Sens.”
levels downward if this is required to achieve
the desired system balance.
Do not increase any “Input Sens.” setting
for any channel(s) of any amplifier in the
system beyond the maximum level established
during the procedure outlined in Appendix
A (page 12). Doing so will result in audible
distortion and 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 multiple speakers, each
dedicated to reproducing a specific frequency
range. Filters are used to select which frequency
range is sent to each section of a speaker system.
The division of frequency ranges to different
speakers can be done with passive filters (coils
and/or capacitors between the amplifier outputs
and the speakers), which are acceptable and
commonly used for filtering between mid-
range speakers and tweeters. Filtering between
subwoofer systems and satellite speaker systems
is best done with active filters, which cut off
frequency content at the input to the amplifier.
Active filters are more stable than passive filters
and do not introduce extraneous resistance,
which can degrade subwoofer performance.
The active filter built into the M1700 can be
used to eliminate potentially harmful and/or
undesired frequencies from making their way
through the amplifier sections to the speaker(s).
This serves to improve tonal balance and to avoid
distortion and possible speaker failure. Correct
use of these filters can substantially increase the
longevity and fidelity of your audio system.
The M1700 employs a sophisticated, variable,
low-pass active filter for its internal channel. This
feature is designed to attenuate frequencies above
its filter frequency, so that the system’s subwoofers
do not reproduce any audible midrange content.
2) Filter Operation: The low-pass filter in the
M1700 is fully variable between 40 Hz and
200 Hz via the “Filter Freq.” control knob
and features the ability to select between a
moderate “12dB” per octave or a steep “24dB”
per octave slope via the “Mode/Slope” switch.
Depending on the subwoofer system and
the vehicle, different slopes may be required
to produce a smooth transition to the mid-
bass speakers in the system. Experiment to
find the slope which best matches the acoustic
requirements of your system.
3) Precise Frequency Selection: The filter
JL AUDIO M1700 7

frequency markings on the front panel of
the amplifier are for reference purposes and
are generally accurate to within 1/3 octave
or better. If you would like to select the filter
frequency with a higher level of precision,
consult Appendix B (page 13) of this manual.
This chart gives you a more accurate frequency
for each of the forty detented positions of the
frequency selection control. This method can
be very useful if the amplifier is mounted in
a location where you can’t see the front panel
markings easily.
4) Defeating the Amplifier Filter: The Low-
Pass filter can also be defeated completely,
by switching the “Mode/Slope” switch to the
“Off” position. This is useful if you are using
an external active crossover in the system.
Keep in mind that turning the internal
crossover off also defeats the “Bass Boost”
processing (see next section for details). With
the internal crossover turned off, the M1700’s
upper frequency response limit is 250 Hz, due
to its bass-specific Class D design.
BASS BOOST CONTROLS
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
PowerP
rotect
CH 2 (Right)
Pre-Outs
1) “Bass Boost”: This switch allows the user
to activate a 6 dB boost centered at 48 Hz.
The “Filter Mode” switch in the “Amplifier
Controls” section must be in the “LP” position
for the bass boost to be functional.
2) “Remote Bass Port”: This port allows you to
connect an optional remote boost knob (sold
separately as JL Audio Model RBC-1) that
can be mounted near the head unit. With
the RBC-1 connected, the boost is no longer
limited to 0 or +6 dB, allowing a range of 0 to
+12 dB of boost to be selected.
PREOUTS
The M1700 incorporates a pass-through
preamp output section, so that additional
amplifiers can be easily added to the system.
The preamp output delivers the same signal that
is connected to the M1700’s inputs.
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
Powe
rProtect
CH 2 (Right)
Pre-Outs
8 JL AUDIO M1700

The preamp output signal is not affected by the
“Bass Boost” processing selected for the amplifier
or by any crossover filter selected (if the input
signal is full-range, the preamp output will be
full-range).
The signal level of the “Preamp Output” is
line-level (low voltage), regardless of the position
selected via the M1700’s “Input Voltage” switch.
An additional amplifier connected to these
preamp outputs should have its input voltage
switch set to the “Low” position.
If you plan to use the “Pre-Outs” to feed
a stereo amplifier, you must connect a
stereo signal to the input of the amplifier.
A mono signal into the amplifier will result
in a mono signal out of the preamp output.
SPEAKER OUTPUTS
The M1700’s speaker outputs are designed to
accept 16 AWG - 8 AWG wire.
The M1700 is designed to deliver power into
speaker loads equal to or greater than 2 ohms.
To connect the speaker wires to the amplifier,
first back out the set screws own the top of the
terminal block, using the supplied 2.5 mm hex
wrench. Strip 1/2 inch (12 mm) of insulation from
the end of each wire and insert the bare wire into
the terminal block, seating it firmly so that no
bare wire is exposed. While holding the wire in
place, tighten the set screw firmly, taking care not
to strip the head of the screw.
Speaker loads below 2 ohms nominal are not
recommended and may cause the amplifier
to initiate a protection mode which reduces
power output.
You will notice that there are two “+” positive
connections and two “–” negative connections.
This is to facilitate multiple speaker wiring.
The two positive and two negative connections
are connected in parallel inside the amplifier.
Connecting two speakers, each to one set of
positive and negative terminals, will result in a
parallel speaker connection. If only connecting
one pair of speaker wires, it is not necessary to
use both sets of connections.
JL AUDIO M1700 9

AMPLIFIER STATUS INDICATOR LIGHTS &
PROTECTION CIRCUITRY
There are two status indicator lights on the
input / control end of the amplifier.
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
PowerProtect
CH 2 (Right)
Pre-Outs
1) “Power” (Green): lights to indicate that the
amplifier is turned on and operating normally.
2) “Protect” (Red): Indicates that the amplifier
protection circuitry has been activated to
prevent product failure due to a short-circuit
or a dangerously low impedance connected to
the amplifier output(s). Connecting the speaker
outputs to an impedance lower than 2 ohms
will cause this protection mode to activate.
When this protection mode is activated, the
amplifier will reduce it maximum power
output to protect its circuitry, which will
manifest itself as increased distortion. When
the problem is corrected, the amplifier will
return to normal operation.
Advanced Rollback Thermal protection
Unlike conventional thermal protection
systems, which shut down an amplifier when it
overheats, this system protects the amplifier by
gradually reducing power output if the amplifier’s
safe operating temperature is exceeded. The
amplifier will continue to operate and return
to normal power output once its temperature
returns to a normal range.
Low-Voltage protection:
If the vessel’s supply voltage drops below 10
volts, the entire amplifier will shut itself off to
protect its internal circuitry. The green “Power”
indicator will turn off when this occurs. The
amplifier will turn back on when voltage climbs
back above 10 volts. This may happen in a rapid
cycle when bass-heavy program material causes
a weak charging system to dip below 10 volts
momentarily. If this is happening in your system,
turn your audio system off and have your power
wiring, ground connections and charging
system inspected.
10 JL AUDIO M1700