background image
7 page 2-5
7 page 6-9
7 página 10-13
© B64-3935-00/00 (KV/EV)
Take the time to read through this instruction manual. Familiarity
with installation and operation procedures will help you obtain the
best performance from your new power amplifier.
For your records
Record the serial number, found on the back of the unit, in the spaces
designated on the warranty card, and in the space provided below. Refer
to the model and serial numbers whenever you call upon your Kenwood
dealer for information or service on the product.
Model KAC-8404 Serial number
US Residence Only
Register Online
Register your Kenwood product at
w w

background image
2 English
Safety precautions
To prevent injury or fire, take the following precautions:
· When extending the ignition, battery, or ground wires, make sure to use
automotive-grade wires or other wires with a 8 mm² (AWG 8) or more to
prevent wire deterioration and damage to the wire coating.
· To prevent a short circuit, never put or leave any metallic objects (such as coins
or metal tools) inside the unit.
· If the unit starts to emit smoke or strange smells, turn off the power
immediately and consult your Kenwood dealer.
· Do not touch the unit during use because the surface of the unit becomes hot
and may cause burns if touched.
· Mounting and wiring this product requires skills and experience. For safety's
sake, leave the mounting and wiring work to professionals.
To prevent damage to the machine, take the following
· Be sure the unit is connected to a 12V DC power supply with a negative
ground connection.
· Do not open the bottom covers of the unit.
· Do not install the unit in a spot exposed to direct sunlight or excessive heat
or humidity. Also avoid places with too much dust or the possibility of water
· When replacing a fuse, only use a new one with the prescribed rating. Using a
fuse with the wrong rating may cause your unit to malfunction.
· To prevent a short circuit when replacing a fuse, first disconnect the wiring
· If you experience problems during installation, consult your Kenwood dealer.
· If the unit does not seem to be working right, consult your Kenwood dealer.
· Take the battery wire for this unit directly from the battery. If it's connected to
the vehicle's wiring harness, it can cause blown fuses etc.
· If a buzzing noise is heard from the speakers when the engine is running,
connect a line noise filter (optional) to each of the battery wire.
· Do not allow the wire to directly contact the edge of the iron plate by using
· Connect the ground wire to a metal part of the car chassis that acts as an
electrical ground passing electricity to the battery`s negative
- terminal. Do
not turn the power on if the ground wire is not connected.
· Be sure to install a protective fuse in the power cord near the battery. The
protective fuse should be the same capacity as the unit's fuse capacity or
somewhat larger.
· For the power cord and ground, use a vehicle type (fireproof ) power wring
cord with a current capacity greater than the unit's fuse capacity. (Use a power
wiring cord with a diameter of 8 mm² (AWG 8) or greater.)
· When more than one power amplifier are going to be used, use a power
supply wiring wire and protective fuse of greater current-handling capacity
than the total maximum current drawn by each amplifier.
Speaker selection
· The input power of the speakers that are going to be connected should be
greater than the output power (in Watts) of the amplifier. Use of speakers
having input power ratings that are less than the output power of the amplifier
will cause smoke to be emitted as well as damage.
· The impedance of the speakers that are going to be connected should be 2
or greater (for stereo connections), or 4 or greater (for bridged connections).
When more than one set of speakers are going to be used, calculate the
combined impedance of the speakers and then connect suitable speakers to
the amplifier.
Combined impedance
Cleaning the unit
If the front panel gets dirty, turn off the power and wipe the panel with a dry
silicon cloth or soft cloth.
Do not wipe the panel with a hard cloth or a cloth dampened by volatile
solvents such as paint thinner and alcohol. They can scratch the surface of the
panel and/or cause the indicator letters to peel off.
To prevent battery from running out
When the unit is used in the ACC ON position without turning the engine ON, it
depletes the battery. Use it after starting the engine.
This equipment may generate or use radio frequency energy. Changes or
modifications to this equipment may cause harmful interference unless the
modifications are expressly approved in the instruction manual. The user could
lose the authority to operate this equipment if an unauthorized change or
modification is made.
This equipment has been tested and found to comply with the limits for a
Class B digital device, pursuant to Part 15 of the FCC Rules. These limits are
designed to provide reasonable protection against harmful interference in
a residential installation. This equipment may cause harmful interference to
radio communications, if it is not installed and used in accordance with the
instructions. However, there is no guarantee that interference will not occur in a
particular installation. If this equipment does cause harmful interference to radio
or television reception, which can be determined by turning the equipment off
and on, the user is encouraged to try to correct the interference by one or more
of the following measures:
· Reorient or relocate the receiving antenna.
· Increase the separation between the equipment and receiver.
· Connect the equipment into an outlet on a circuit different from that to which
the receiver is connected.
· Consult the dealer or an experienced radio/TV technician for help.
Declaration of Conformity with regard to the EMC
Directive 2004/108/EC
Kenwood Corporation
2967-3 Ishikawa-machi, Hachioji-shi, Tokyo, 192-8525 Japan
EU Representative's:
Kenwood Electronics Europe BV
Amsterdamseweg 37, 1422 AC UITHOORN, The Netherlands
Information on Disposal of Old Electrical and Electronic
Equipment (applicable for EU countries that have adopted
separate waste collection systems)
Products with the symbol (crossed-out wheeled bin) cannot be
disposed as household waste.
Old electrical and electronic equipment should be recycled at a
facility capable of handling these items and their waste byproducts.
Contact your local authority for details in locating a recycle facility
nearest to you. Proper recycling and waste disposal will help conserve
resources whilst preventing detrimental effects on our health and the
This Product is not installed by the manufacturer of a vehicle on the production
line, nor by the professional importer of a vehicle into an EU Member State.

background image
Part name
External View
Number of Items
Self-tapping screws
(ø4 × 16 mm)
Terminal cover
(Power terminal)
Speaker level input cable
Hexagon wrench
Installation procedure
Since there are large variety of settings and connections possible according to
applications, read the instruction manual well to select the proper setting and
1.Remove the ignition key and disconnect the negative
- terminal of the battery
to prevent short circuits.
2.Set the unit according to the intended usage.
3.Connect the input and output wires of the units.
4.Connect the speaker wires.
5.Connect the power wire, power control wire and grounding wire following this
6.Install the installation fittings in the unit.
7.Attach the unit.
8.Connect the negative
- terminal of the battery.
· Do not install in the below locations;
(Unstable location, In a location that interferes with driving, In a location
that gets wet, In a dusty location, In a place that gets hot, In a place that
gets direct sunlight, In a location that gets hit by hot air)
· Do not install the unit under the carpet. Otherwise heat build-up occurs and
the unit may be damaged.
· Install this unit in a location which allows heat to easily dissipate.
Once installed, do not place any object on top of the unit.
· The surface temperature of the amplifier will become hot during use. Install
the amplifier in a place where people, resins, and other substances that are
sensitive to heat will not come into contact with it.
· This unit has cooling fan to decrease the internal temperature. Do not
mount the unit in a place where the cooling fan and ducts of the unit are
blocked. Blocking these openings will inhibit the cooling of the internal
temperature and result in malfunction.
· When making a hole under a seat, inside the trunk, or somewhere else in
the vehicle, check that there is nothing hazardous on the opposite side such
as a gasoline tank, brake pipe, or wiring harness, and be careful not to cause
scratches or other damage.
· Do not install near the dashboard, rear tray, or air bag safety parts.
· The installation to the vehicle should securely fasten the unit to a place in
which it will not obstruct driving. If the unit comes off due to a shock and
hits a person or safety part, it may cause injury or an accident.
· After installing the unit, check to make sure that electrical equipment
such as the brake lamps, turn signal lamps and windshield wipers operate
Protection function
The protection function is activated in the following situations:
This unit is equipped with a protection function for protecting this unit and your
speakers from various accidents or problems that can occur.
When the protection function is triggered, the Power indicator goes OFF and the
amplifier stops operating.
· When a speaker wire may be short-circuited.
· When a speaker output contacts ground.
· When the unit malfunctions and a DC signal is sent to the speaker output.
· When the internal temperature is high and unit won't operate.
· When a ground wire of the center unit (cassette receiver, CD receiver, etc.)
or this unit is not connected to a metal part serving as an electrical ground
passing electricity to the battery's negative
- terminal.
280 mm
242 mm
260.5 mm
Installation board, etc.
(thickness : 15 mm or more)
Self-tapping screw
(ø4 × 16 mm)
Hexagon socket
head cap screw
(M4 × 8 mm)
Hexagon wrench
Dressing cover
Cooling fan

background image
4 English
RCA cable or Speaker level input connection
(CD receiver, etc.)
RCA cable*
· Bridged Connections
Ground wire*
Battery wire*
Protective Fuse*
Power control wire
To prevent fire caused by a short in the wiring,
connect a fusible link or breaker nearby the
battery's positive terminal.
· If sound is not output normally, immediately turn
power off and check connections.
· Be sure to turn the power off before changing the
setting of any switch.
· If the fuse blows, check wires for shorts, then
replace the fuse with one of the same rating.
· Check that no unconnected wires or connectors
are touching the car body. Do not remove
caps from unconnected wires or connectors to
prevent short circuits.
· Connect the speaker wires to appropriate speaker
connectors separately. Sharing the negative wire
of the speaker or grounding speaker wires to the
metal body of the car can cause this unit to fail.
· Do not connect cables and leads to both RCA
cable input jacks and the speaker level input
terminals simultaneously, for this may cause
malfunction or damage.
Speaker level input connections
· The genuine-accessory car stereo shall have a
maximum power output of no more than 40 W.
· The power is turned on and off as the unit
detects input signal (Signal Sensing Turn-ON).
There fore it is not necessary to connect the
power control wire.
Speaker output terminals
· Stereo Connections:
The speakers to be connected should have an
impedance of 2 or greater.
· Bridged Connections:
Make connections to the LEFT channel
and the RIGHT channel
The speakers to be connected should have an
impedance of 4 or greater.
40 A × 1
A channel
Left speaker
A channel
Right speaker
B channel
Right speaker
B channel
Left speaker
A channel
Speaker (Bridged)
B channel
Speaker (Bridged)
A channel input
B channel input
Terminal cover
Power wire and Speaker wire connection
· RCA cable connections
· Speaker level input connections
Power control wire*
(RCA cable connection)
Genuine-accessory car
stereo (No line output
center unit etc.)
Cable Color of the connector
A channel
A channel
9 Gray
· Gray/Black
B channel
9 Green
· Green/Black
B channel
9 Purple
· Purple/Black
* Commercially available parts
· Stereo Connections
Lead terminal*

background image
Primary Power Output Ratings (RMS Watts per
channel @ 4 ohms, 1 % THD+N)
50 W × 4
Signal to Noise Ratio
(Reference: 1Watt into 4 ohms)
80 dBA
Audio Section
Max Power Output
600 W (150 W × 4)
Rated Power Output (+B = 14.4 V)
Normal (4 ) (20 Hz ­ 20 kHz, 0.08 % THD)
50 W × 4
Normal (4 ) (DIN : 45324 , +B = 14.4V)
50 W × 4
Normal (2 ) (1 kHz, 0.8 % THD)
75 W × 4
Bridged (4 ) (1 kHz, 0.8 % THD)
180 W × 2
Frequency Response (+0, ­3 dB)
5 Hz ­ 50 kHz
Sensitivity (rated output)
0.2 V ­ 5.0 V
Input Impedance
10 k
Signal to Noise Ratio
100 dB
Low Pass Filter Frequency (-12 dB/oct.)
50 ­ 200 Hz (variable)
High Pass Filter Frequency (-12 dB/oct.)
50 ­ 200 Hz (variable)
Bass Boost Circuit (40 Hz) (B channel)
0/ +18 dB
Operating Voltage
14.4 V (11 ­ 16 V allowable)
Current Consumption
40 A
Installation Size (W × H × D)
280 × 59 × 238 mm
11 × 2-5/16 × 9-3/8 inch
2.8 kg (6.2 lbs)
* Specifications subject to change without notice.
Troubleshooting Guide
What might appear to be a malfunction in your unit may just be the result
of slight misoperation or miswiring. Before calling service, first check the
following table for possible problems.
No sound. (Blown fuse.)
Input (or output) cables are disconnected.
Connect the input (or output) cables.
Protection circuit may be activated.
Check connections by referring to <Protection function>.
Volume is too high.
Replace the fuse and use lower volume.
The speaker cord is shorted.
After check the speaker cord and fixing the cause of the short, replace the
The output level is too small (or too large).
The input sensitivity adjusting control is not set to the correct position.
Adjust the control correctly referring to <Controls>.
The sound quality is bad. (The sound is distorted.)
The speakers wire are connected with wrong
9 / · polarity.
Connect them properly checking the
9 / · of the terminals and wires
A speaker wire is pinched by a screw in the car body.
Connect the speaker wire again so that it is not pinched by anything.
The switches may be set improperly.
Set switches properly by referring to <Controls>.
The control panel locates under the dressing cover. Remove the cover to
access to its controls for adjustment. (See page 3)
1 Power indicator
When the power is turned on, the Power indicator lights.
If the Power indicator does not light when the power is turned on, the
protection function may be activated. Check whether there is any indication
of trouble. Refer to <Protection function> (page 3).
2 Illumination
Sets the cutoff frequency when the "FILTER" switch is set to "LPF" or "HPF".
Set this control according to the pre-output level of the center unit connected
with this unit, or to the maximum power output of the genuine-accessory car
Use the diagram on the right as a guide.
The sensitivities of amplifiers A and B can be adjusted independently.
5 FILTER switch (
This switch allows to apply high-pass or low-pass filtering to the speaker
· HPF (High-Pass Filter) position:
The filter outputs the band of higher frequencies than the frequency set
with the "FILTER FREQUENCY" control.
· OFF position:
The entire bandwidth is output without filtering.
· LPF (Low-Pass Filter) position:
The filter outputs the band of lower frequencies than the frequency set with
the "FILTER FREQUENCY" control.
6 OPERATION switch (
The amplification methods of the signals input to amplifiers A and B can be
selected independently according to the setting of this switch.
· STEREO position:
The amplifier can be used as a stereo amplifier.
· MONO (Lch) position:
Amplifies the signal input from the left side only. Set to this position and
make bridged connections to use as a high-power monaural amplifier.
7 BASS BOOST switch (
Setting this switch to "ON" emphasizes the bass.
You can use the BASS BOOST for amplifier B only.
· ON position:
BASS BOOST is +18 dB.
· OFF position: