KENWOOD KAC-819
Owner's Manual

Controls
0
FUSE (30A)
POWER IN BATT

10 0.5 0.3 1 2 34 5
SUBWOOFER AMPLIFIER

� SERVO II
P.CON(REMOTE)

SPEAKER OUTPUT

� SERVO II

OFF 15Hz 25Hz

OFF 6dB 12dB

SPEAKER LEVEL INPUT

30

GND

LINE IN
120 0.5 150 170 1 2 3 4 0.3

LEFT R

RIGHT

L GND

INFRASONIC

BASS BOOST

100 70 50

200

5

0.2

SUBWOOFER AMPLIFIER

15

LPF FREQUENCY(Hz)

INPUT SENSITIVITY(V)

1

23

4

5

6

OFF

15Hz

25Hz

OFF

6dB

12dB

100 70

120

150 170

0.5 1 2 3 4

0.3

!@

#

(V)

0.2

KAC-819

INFRASONIC

BASS BOOST

50

200

5

0.2

(W)

MAXIMUM POWER

LPF FREQUENCY(Hz)

INPUT SENSITIVITY(V)

25W or greater Do not use this terminal for power source grounding. This unit will be damaged if the power source grounding wire is connected to this terminal.

Power indicator

7 Operations of the following control and switches are required in accordance with the centre unit and speakers connected with this unit.

8

9

0 � A speaker wire may be short-circuited. � A speaker output may be in contact with the ground. � When the internal temperature is high and unit won�t operate. � The sigma servo connection may be erroneous. � The fuse of this unit may be blown. � The unit may be malfunctioning and sending DC signal to the speaker output. � The grounding wire of this unit may not be connected with a metallic part which is electrically connected with the negative terminal of the battery. � The power control wire may not be connected to this unit. � The grounding wire of the centre unit (cassette receiver, CD receiver, etc.) may not be connected with a metallic part which is electrically connected with the negative terminal of the battery.

1 FUSE (30 A � 1) 2 Battery terminal 3 Ground terminal 4 Power control (REMOTE) terminal 5 Speaker output terminals
As this unit accepts speakers with a minimum impedance of 2 ohms, connect speakers with 2-ohm or higher impedance to these terminals. 2CAUTION The rated input of the speakers should be no less than the maximum output of the amplifier. Otherwise malfunction may result.

etc. Setting this switch to "15 Hz" or "25 Hz" cuts the frequencies below the respective frequency. This improves the reproduction performance of the speakers by eliminating unnecessary oscillations which will not become sound.

@ LINE IN terminal # Speaker level input terminals
A center unit with no RCA output can still be connected to the speaker output. Again, even without a power control signal, the power is switched ON/OFF automatically by the speaker signal.

8 BASS BOOST switch
Setting this switch to "+6dB" or "+12dB" emphasizes the bass.

9 LPF(Low-Pass Filter) FREQUENCY control 0 INPUT SENSITIVITY control
This control adjusts the frequency band output from this unit. 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 stereo. Use the diagram on the right as a guide. NOTE For the pre-output level or the maximum power output, refer to the �Specifications� in the instruction manual of the center unit.

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.

6 SIGMA SERVO II terminals
2CAUTION Be sure to make proper connections to the SIGMA SERVO II terminals. Incorrect connection may result in lack of sound output or other malfunctions.

� 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.

7 INFRASONIC FILTER switch
Ultralow frequencies that cannot be reproduced even by a subwoofer speaker do not become sound but become unnecessary oscillations, which affect the sound by causing distortion,

! RCA cable ground lead terminal
When using an RCA cable with a ground lead attached, connect the ground lead to this terminal.
2CAUTION

Connection
NOTE

*�Commercially available parts

Sigma servo feed back
The sound reproduced through conventional amplifiers is distorted due to the counterelectromotive force produced in the oscillating system of the speaker. The counterelectromotive force is particularly high with the woofer which requires a large drive mass.The sigma servo connection reduces distortion caused by the counterelectromotive force by including the circuit up to the speaker terminals in the negative feedback loop. This makes it possible to drive speakers with more fidelity to the input signals and create a sharp bass sound image with few feeling of noise interference. NOTE The speaker wires and sigma servo wires should be distributed along the same paths. 2CAUTION � The extension of the negative feedback loop to include the speaker terminals makes it necessary to connect the sigma servo terminals correctly. Incorrect connection may result in sound degradation or other malfunction. If sound is not reproduced normally, check the connection of the sigma servo terminals, etc. � If the Sigma servo terminals are not connected, the sound may fluctuate or noise may occur. Be sure to connect the Sigma servo terminals correctly. � When connecting speakers in a parallel configuration, use speakers with an impedance of 4 ohms or more. Connecting speakers with smaller impedance than 4 ohms will cause malfunction. � The rated input of the speakers connected to this unit should be no less than the maximum output of the amplifier. Otherwise malfunction may result. Be specially careful in this when connecting speakers in a parallel configuration.

For safe installation, read "Installation procedure" before starting work.

� RCA cable connection
CENTER UNIT (Cassette receiver, CD receiver, etc.)

� Speaker level input connection
Genuine-accessory car stereo (No line output center unit etc.)

RCA cable*

Speaker

#
LEV
15Hz 6dB

INPU EL IGHT R

T

!
G ND
OFF

K EA SP LEFT
12dB

ER

25Hz

OFF

LINE IN
120 150 170 1 2 3 45 0.5 0.3

SPEAKER LEVEL INPUT LEFT RIGHT R

INFRASONIC

BASS BOOST

100 70 50

L GND
0.2

SUBWOOFER AMPLIFIER

200

LPF FREQUENCY(Hz)

INPUT SENSITIVITY(V)

ACC Power control wire* Car fuse box Battery

� Basic sigma servo connection
Lead terminal*

� Series connection

4

Lead terminal*
II

56
ER S PEAK O UTPU

T

�S

ERVO

FUSE (30A)

POWER IN BATT

� SERVO II
P.CON(REMOTE)

SPEAKER OUTPUT

� SERVO II
�

30

GND

VO SER

II

2CAUTION Make this wire as short as possible.

23
� Parallel connection (1)
Subwoofer Terminal cover Distribute the speaker wires and sigma servo wires along the same paths. Battery wire* Ground wire* 2CAUTION The speaker wires connected to this unit should be thick enough to supply the current capacity of two speakers.

� Parallel connection (2)

2CAUTION This connection is possible only when the speakers are identical and the speaker wires are also of the same type and length.

Protective Fuse*

+

-

� Simplified sigma servo connection
In case any of the connection examples above cannot be used or if the speakers cannot be connected to the speaker terminals, connect them to this unit as shown in the figure.

Battery

� Speaker level input terminals (#)
When the genuine-accessory car stereo power is turned ON/OFF, check that the power to this unit has followed suit. In some cases, the power control is not correctly operated by the genuine-accessory car stereo. If this is the case, connect the ACC or power control signal to the P.CON(REMOTE) terminal. 2CAUTION � 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.