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Installation procedure

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 cables of the

units.

4. Connect the center unit and this unit according

to the required application.

5. Connect the speaker wires and sigma servo

feed back wires.

6. Connect the power wire, power control wire

and grounding wire following this order.

7. Install the unit in the car.
8. Connect the negative 

-

terminal of the battery.

9. Turn power ON and ensure that sound is output

normally.

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 perform the sigma servo connection
correctly.

• Be sure to make correct connections of the

sigma servo terminals.

• 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 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.

Power terminal (

23

)

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.

Accessories

Installation

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.

• 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.

• After installing the unit, check to make sure that

electrical equipment such as the brake lamps, turn
signal lamps and windshield wipers operate
normally.

2

CAUTION

2

CAUTION

2

WARNING

KAC-819

MONO POWER AMPLIFIER

INSTRUCTION MANUAL

© PRINTED IN USA  B64-1964-00 (KM/EM)

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-819   Serial number

Specifications

Specifications subject to change without notice.

Audio Section

Max Power Output (2 

½

) ................................................................................................450 W 

´

1

Max Power Output 

(4 

½

) ................................................................................................300 W 

´

1

Rated Power Output (4 

½

) ............................................150 W 

´

1 (20 Hz ~ 200 Hz, 0.08 % THD)

Rated Power Output 

(4 

½

) ........................................................150 W 

´

1 (DIN45324, +B=14.4V)

Rated Power Output 

(2 

½

) ............................................................230 W 

´

1 (100 Hz, 0.8 % THD)

Frequency Response (+0, –3 dB) ............................................................................5 Hz ~ 200 Hz
Sensitivity (MAX) ..............................................................................................0.2 V (rated output)

Sensitivity

(MIN) ..............................................................................................5.0 V (rated output)

Signal to Noise Ratio ............................................................................................................100 dB
Input Impedance ....................................................................................................................10 k

½

Damping Factor ..............................................................................More than 2000 (at 

·

connect)

Low Pass Filter Frequency (18 dB/oct.) ........................................................50 ~ 200 Hz (variable)
Infrasonic Filter Frequency (18 dB/oct.) ..........................................................................15 / 25 Hz
Bass Boost Circuit (90 Hz) ................................................................................................6 / 12 dB

General

Operating Voltage ..............................................................................14.4 V (11 ~ 16 V allowable)
Current Consumption (100 Hz, 10 % THD)..............................................................................21 A
Dimensions (W 

´

´

D) ..................................................................................290 

´

56 

´

200 mm

..................................................................................................

11-7/16 

´

2-3/16 

´

7-14/16 inch

Weight......................................................................................................................3.1 kg (6.8 lbs)

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 5mm

2

(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.

To prevent damage to the machine, take the
following precautions:

• 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.

• To prevent a short circuit when replacing a fuse, first

disconnect the wiring harness.

• If you experience problems during installation,

consult your Kenwood dealer.

• If the unit does not seem to be working right, consult

your Kenwood dealer.

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.

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.

Wiring

• 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 Grommets.

• 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.

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.

• Use speakers that have an impedance of 2

½

or

greater. 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.

2

CAUTION

NOTE

2

CAUTION

2

WARNING

Maximum Current Drawn 

Protective Fuse

Cross-sectional Area of

Wiring Wire (AWG)

21 A

40 A 

´

1 [20 A 

´

2]

5 mm

2

(AWG 10) or

greater 

´

1

Example: One Power Amplifier Is Used 

Part name

Number of

Items

External

View

Terminal cover

(Power terminal)

1

Self-tapping screws

(ø4 

´

16 mm)

4

Installation board, etc.
(thickness : 15 mm or
more) 

Self-tapping screw
(ø4 

´

16 mm) 

PROBLEM

POSSIBLE CAUSE

SOLUTION

No sound.
(No sound from one side.)

(Blown fuse.)

The output level is too
small (or too large).

The sound quality is bad.
(The sound is distorted.)

• Input (or output) cables are

disconnected.

• Protection circuit may be

activated.

• The connection of the sigma

servo terminals is wrong.

• Volume is too high.

• The speaker cord is shorted.

The input sensitivity adjusting
control is not set to the correct
position.

• The speakers wire are

connected with wrong 

+

-

polarity.

• A speaker wire is pinched by a

screw in the car body.

• The switches may be set

improperly.

• Connect the input (or output)

cables.

• Check connections by referring

to "Power indicator".

• Check the connection referring

to "Sigma servo feed back".

• Replace the fuse and use lower

volume.

• After check the speaker cord and

fixing the cause of the short,
replace the fuse.

Adjust the control correctly
referring to "Controls".

• Connect them properly checking

the 

+

-

of the terminals and

wires well.

• Connect the speaker wire again

so that it is not pinched by
anything.

• Set switches properly by

referring to "Controls".

½

½

4

½

4

½

4

½

4

½

20 A

20 A

20 A

20 A

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.

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