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.
PROBLEM
POSSIBLE CAUSE
SOLUTION
No sound.
(No sound from one side.)
• Input (or output) cables are
disconnected.
• Connect the input (or output)
cables.
• Protection circuit may be
activated.
• Check connections by referring
to "Power indicator".
• Replace the fuse and use lower
volume.
• After check the speaker cord and
fixing the cause of the short,
replace the fuse.
KAC-849
(Blown fuse.)
• Volume is too high.
• The speaker cord is shorted.
KAC-749S
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".
4-CHANNEL POWER AMPLIFIER
INSTRUCTION MANUAL
The sound quality is bad.
(The sound is distorted.)
• The speakers wire are
connected with wrong + / -
polarity.
• Connect them properly checking
the + / - of the terminals and
wires well.
• 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 "System examples".
Specifications
Specifications subject to change without notice.
Audio Section .....................................................................KAC-849 KAC-749S
Max Power Output (4 Ω)
4 Channel Mode ...................................................................100 W × 4 80 W × 4
3 Channel Mode...............................................100 W × 2 + 300 W × 1 80 W × 2 + 250 W × 1
2 Channel Mode ...................................................................300 W × 2 250 W × 2
Rated Power Output (4 Ω)
4 Channel Mode (20 Hz ~ 20 kHz, less than 0.08 % THD).....50 W × 4 40 W × 4
4 Channel Mode (DIN45324, +B=14.4V)................................50 W × 4 40 W × 4
3 Channel Mode (20 Hz ~ 20 kHz, 0.08 % THD) + (1 kHz, 0.8 % THD)
...........................................................................50 W × 2 + 150 W × 1 40 W × 2 + 120 W × 1
2 Channel Mode (1 kHz, 0.8 % THD)....................................150 W × 2 120 W × 2
Rated Power Output (2 Ω)
4 Channel Mode (1 kHz, 0.8 % THD)......................................75 W × 4 60 W × 4
Frequency Response (+0, –3 dB)......................................5 Hz ~ 50 kHz 5 Hz ~ 50 kHz
Signal to Noise Ratio ....................................................................100 dB 100 dB
Sensitivity (MAX) (rated output).......................................................0.2 V 0.2 V
Sensitivity (MIN) (rated output)........................................................5.0 V 5.0 V
Input Impedance ............................................................................10 kΩ 10 kΩ
Low Pass Filter Frequency (12 dB/oct.) (Variable)................50 ~ 200 Hz 50 ~ 200 Hz
High Pass Filter Frequency (12 dB/oct.) (Variable)................50 ~ 200 Hz 50 ~ 200 Hz
Bass Boost Circuit (90 Hz)................................................................6 dB 6 dB
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-849/749S Serial number
General..................................................................................KAC-849 KAC-749S
Operating Voltage (11 ~ 16 V allowable) .......................................14.4 V 14.4 V
Current Consumption (1 kHz, 10 % THD) ........................................31 A 26 A
Dimensions (W × H × D)...........................................261 × 57 × 256 mm 261 × 57 × 256 mm
......................................................................(10-1/4×2-1/4×10-1/16 in.) (10-1/4×2-1/4×10-1/16 in.)
Weight................................................................................3.5 kg (7.7 lb) 3.5 kg (7.7 lb)
© PRINTED IN USA B64-1969-00 (KM/EM)
■ Wiring
Safety precautions
■ Accessories
Installation procedure
1.Remove the ignition key and disconnect the
negative - terminal of the battery to prevent
short circuits.
• If a buzzing noise is heard from the speakers
External
View
Number of
Items
when the engine is running, connect a line noise
Part name
2WARNING
filter (optional) to each of the battery wire.
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 5mm (AWG10) 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.
• Do not allow the wire to directly contact the edge
of the iron plate by using Grommets.
Terminal cover
(Power terminal)
1
4
1
2.Set the unit according to the intended usage.
3.Connect the input and output cables of the
units.
• 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 attach a protective fuse into the
battery wire close to the battery. Use a
protective fuse having a capacity that is about 10
A higher than the maximum current drawn by the
amplifier.
• Use vehicle-type (fire-resistant) power supply
wiring wire for the battery wire and the ground
wire. The current capacity of the power supply
wiring wire should be about 10 A higher than that
of the protective fuse capacity (which means
about 20 A higher than the maximum current
drawn by the amplifier).
• 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.
Self-tapping screws
2
(ø4 × 16 mm)
4.Connect the speaker wires.
Speaker level input
cable
5.Connect the power wire, power control wire
and grounding wire following this order.
6.Install the unit in the car.
7.Connect the negative - terminal of the battery.
Installation
2WARNING
Since the power amplifier has no parts which require
operation, it can be installed at a position away from
the driver’s seat without any hindrances.
As generally accepted positions for its installation,
places such as inside the trunk, etc. can be
considered.
To prevent fire caused by a short in the wiring,
connect a fusible link or breaker nearby the
battery’s positive terminal.
2CAUTION
• Be sure to turn the power off before changing the
setting of any switch.
2CAUTION
2CAUTION
To prevent damage to the machine, take the
following precautions:
• If the fuse blows, check wires for shorts, then
replace the fuse with one of the same rating.
• Check that no unconnected cables or connectors
are touching the car body. Do not remove caps from
unconnected cables 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.
• After installation, check that the brake lamps,
winkers, and wipers work properly.
• 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.
• 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.
• Be sure the unit is connected to a 12V DC power
supply with a negative ground connection.
• Do not open the top or 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
splashing.
• 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.
Example: One Power Amplifier Is Used
Maximum Current Drawn
Protective Fuse
Cross-sectional Area of
Wiring Wire (AWG)
31 A / 26 A
50 A × 1 [25 A × 2]
2
5 mm (AWG 10) or
greater × 1
• To prevent a short circuit when replacing a fuse, first
disconnect the wiring harness.
25 A
25 A
■ Speaker level input terminals (!)
• The genuine-accessory car stereo shall have a
maximum power output of no more than 40 W.
• Do not connect the speaker output leads from
a power amplifier (Optional) to the speaker
level input terminals of this unit, for this may
cause malfunction or damage.
• 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.
• Connect the power control lead to a power
supply which can be turned ON/OFF by the
ignition key switch (ACC line). With this
connection, shock noise may be generated
when the power of the genuine-accessory car
stereo is switched ON/OFF.
25 A
25 A
NOTE
• If you experience problems during installation,
consult your Kenwood dealer.
• If the unit does not seem to be working right, consult
your Kenwood dealer.
■ Speaker Selection
• The rated input power of the speakers that are
going to be connected should be greater than
the maximum 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.
FCC WARNING
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.
• After installing the unit, check to make sure that
electrical equipment such as the brake lamps, turn
signal lamps and windshield wipers operate
normally.
• The impedance of the speakers that are going to
be connected should be 2Ω or greater (for
stereo connections), or 4Ω 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.
Self-tapping screw
(ø4 × 16 mm)
■ 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.
■ Power terminal (234)
Connect to their respective terminals the power
supply wire, and ground wire, all of which pass
through the associated terminal cover. Once the
connections are complete, place the cover on
the terminal section.
4Ω
2CAUTION
4Ω
4Ω
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.
4Ω
8 Ω
2 Ω
Installation board, etc.
(thickness : 15 mm or more)
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