Power Indicator; Controls; System Examples; Connection - Kenwood KAC-749S Instruction Manual

Controls

POWER IN BRIDGED
SPEAKER
LEFT
OUTPUT
FUSE(40A) BATT. P.CON
1 2 3 4 5
This is a 4 channel amplifier including 2 stereo
amplifiers in a body. One amplifier is referred to as
amplifier A and the other is amplifier B. This unit is
compatible with a large variety of systems by
combining the switches and functions described
in the following.
1 Fuse
40 A × 1 : KAC-849
30 A × 1 : KAC-749S
NOTE
If you can't find the specified capacity fuse at your
store etc., consult your Kenwood dealer.
2 Battery terminal
3 Ground terminal
4 Power control terminal
5 Amplifier A/B SPEAKER OUTPUT
terminals
• Stereo Connections:
When you wish to use the unit as a stereo
amplifier, stereo connections are used.
• Bridged Connections:
When you wish to use the unit as a high-output
monaural amplifier, bridged connections are
used. (Make connections to the LEFT channel (+)
and the RIGHT channel (–) SPEAKER OUTPUT
terminals.)
6 INPUT SENSITIVITY control
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.
The sensitivities of amplifiers A and B can be

System examples

■ 4-channel ■ 4-channel
F
L
A
A
CENTER
R
UNIT
R L
B
R
B
OPERATION INPUT SELECTOR
$
%
A.CH B.CH
A.CH
A B A
STEREO MONO(Lch) STEREO MONO(Lch)
OFF
HPF
80
■ 2-channel
100
80
50 LPF
L
CENTER
50 HPF
A
A.CH
R
UNIT
FILTER FREQUENCY(Hz)
L
B
■ 3-channel
R
OPERATION
INPUT SELECTOR
$
%
A.CH B.CH
A
A B A
STEREO MONO(Lch) STEREO MONO(Lch)
■ 2ch + woofer
B
L
A.CH
A
CENTER
OFF
R
HPF
UNIT
L
B
80
R
100
80
OPERATION
INPUT SELECTOR
$
%
50 LPF
A.CH B.CH
50 HPF
A B A
STEREO MONO(Lch) STEREO MONO(Lch)
A.CH
FILTER FREQUENCY(Hz)
■ 2-channel
■ 2-channel
L
CENTER
A
A
R
UNIT
L
B
B
R
OPERATION
INPUT SELECTOR
$
%
A.CH
A.CH B.CH
A B A OFF
STEREO MONO(Lch) STEREO MONO(Lch)
HPF
80
100
80
50 LPF
50 HPF
A.CH
FILTER FREQUENCY(Hz)
■ Tri-mode
C
L
L L
CENTER
A
R R
UNIT
C
C
L
L L
B
R R
C
OPERATION FILTER
INPUT SELECTOR
A.CH B.CH
$
#
%
BASS BOOST(B.CH)
OFF OFF
A.CH B.CH
HPF LPF HPF LPF OFF ON
A B A
STEREO MONO(Lch) STEREO MONO(Lch)
Principle of Tri-mode
Method of frequency band division using a coil
and capacitor ... in case of 6dB/oct. slope
Coil (L): Passes low frequencies and blocks
high frequencies. (Low pass)
Capacitor (C): Passes high frequencies and
blocks low frequencies. (High pass)
Example:
When it is required to set a crossover
frequency of 120 Hz using speakers with an
impedance of 4 ohms.
fc=Cut of Frequency (Hz)
R=Speaker Impedance (Ω)
BASS BOOST(B.CH)
RIGHT
OFF
A
B
POWER AMPLIFIER
FILTER OPERATION
A.CH B.CH
BASS BOOST(B.CH) A.CH B.CH
OFF OFF
OFF ON STEREO MONO(Lch) STEREO MONO(Lch)
HPF LPF HPF LPF
@ # $
adjusted independently regardless of the position
of the input selector switch.
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.
7 FILTER FREQUENCY control
When the FILTER switch is set to the HPF (High-
Pass Filter) or LPF (Low-Pass Filter) position, the
threshold frequency can be adjusted with this
control.
8 RCA cable ground lead terminal
When using an RCA cable with a ground lead
attached, connect the ground lead to this terminal.
2CAUTION
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.
9 Amplifier A/B LINE IN terminals
0 LINE OUT terminal
These jacks output respectively the signals input to
amplifiers A and B. They always output the stereo
signals regardless of the position of the
OPERATION switch.
! Speaker level input terminals
@ BASS BOOST switch
When the switch is in "ON" position, the bass is
boosted by 6 dB.
The bass boost applies only to the B amplifier.

Connection

NOTE
■ RCA cable connection
Front left speaker
L
R Front right speaker
Rear left speaker
L
R
Rear right speaker
FILTER
B.CH
#
BASS BOOST(B.CH)
OFF
LPF HPF LPF OFF ON @
80
150 100 150 100
100
80
150 150
200 50 LPF 200
7
200 50 HPF 200
B.CH
Left speaker
L
R
Right speaker
L
Subwoofer
R
FILTER
B.CH
#
BASS BOOST(B.CH)
OFF
LPF HPF LPF OFF ON @
80
150 100 150 100
100
80
■ Speaker stereo connection
150 150
200 50 LPF 200
7
200 50 HPF 200
B.CH
L
Left speaker
R
L
Right speaker
R
FILTER
B.CH
#
BASS BOOST(B.CH)
OFF
LPF HPF LPF OFF ON @
80
150 100 150 100
100
80
150 150
200 50 LPF 200
7
200 50 HPF 200
B.CH
Crossover Frequency
0 dB
-3 dB
High pass
L
Subwoofer
(L + R)
159000 159000
C= (µF) = = 331.25 µF
@ fc x R 120Hz x 4Ω
159 x R 159 x 4Ω
L= (mH) = = 5.3 mH
fc 120Hz
2CAUTION
• If you wish to bridge-connect a speaker, the
speaker impedance must be no less than 4
ohms. Connecting a speaker with an
impedance lower than 4 ohms may damage
the unit.
• Be sure to connect capacitors to speakers to
which high frequencies will be passed.
Failure to do so will result in a drop of the
combined impedance with the subwoofer.
• Ensure that the withstand voltage and
current ratings of the capacitors (C) and coils
(L) are sufficient.
FILTER OPERATION LINE IN LINE OUT
A.CH B.CH
A.CH B.CH INPUT SELECTOR +
A B A B
OFF OFF
ON STEREO MONO(Lch) STEREO MONO(Lch) A B A
HPF LPF HPF LPF
1 1 80 80
150 150 L
100 100 100 100
2 0.5 2 0.5
80 80 GND
3 3
150 150
0.3 0.3 SPEAKER LEVEL INPUT
4 4
50 LPF 200 50 LPF 200
(MIN)5 0.2(MAX) (MIN)5 0.2(MAX)
50 HPF 200 50 HPF 200 R
A.CH B.CH
A.CH B.CH
INPUT SENSITIVITY(V)
FILTER FREQUENCY(Hz) L
6 7 8 9 0 !
INPUT SELECTOR
A B A
%
# FILTER switch
This switch allows to apply high-pass or low-pass
filtering to the speaker outputs.
• 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.
The speaker output is automatically turned
monaural (L+R).
$ 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. (The input right signal is not output.)
% INPUT SELECTOR switch
This switch selects the input method of the signals
to be amplified by amplifiers A and B.
• A B position:
Amplifies both of the signals input to amplifiers A
and B.
• A position:
For safe installation, read "Installation procedure" before starting work.
CENTER UNIT (Cassette receiver,
CD receiver, etc.)
8
FILTER OPERATION LINE IN
A.CH B.CH
BASS BOOST(B.CH) A.CH B.CH INPUT SELECTOR
A
OFF OFF MONO(Lch) MONO(Lch) A B A
OFF ON HPF LPF HPF LPF STEREO STEREO
1 1 80 80
150 150 L
100 100 100 100
2 0.5 2 0.5
80 80 GND
3 3
0.3 0.3 150 150
4 4
(MIN)5 0.2(MAX) (MIN)5 0.2(MAX) 50 LPF 200 50 LPF 200
R
50 HPF 200 50 HPF 200
A.CH B.CH
A.CH B.CH
INPUT SENSITIVITY(V)
FILTER FREQUENCY(Hz)
Power control wire*
A L
Lead terminal*
4
5
H T
R IG
E D
ID G
B R
F T
L E
BRIDGED
POWER IN
SPEAKER
LEFT RIGHT
FUSE(40A) BATT. P.CON OUTPUT
BRIDGED
A
B
L R
B L
■ Power wire connection
C
FUSE(40A)
Frequency
Battery wire*
Protective Fuse*
6
40
1
25
0.5
2
15
3 10
A 0.3
(W)
4
B
R
(MIN)5 0.2(MAX)
INPUT SENSITIVITY(V)
KAC-849

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.
■ The protection function is activated
■ Speaker level input connection
Cable Color of the
connector
White
L
RCA cable*
White/Black
A
Gray
R
Gray/Black
A
Green
L
L
Green/Black
B
R
Purple
L
R
Purple/Black
R
B
LINE OUT
+ BASS BOOST(B.CH)
B A B
OFF
SPEAKER LEVEL INPUT
A
B
L R
■ Speaker bridge connection
A R
Lead terminal*
5
H T
R IG
E D
ID G
B R
F T
L E
A
B
POWER AMPLIFIER
BRIDGED
A
B
L R
B R
POWER IN BRIDGED
SPEAKER
OUTPUT LEFT RIGHT
BATT. P.CON
A
B
POWER AMPLIFIER
2 3 4
Lead terminal*
Terminal cover
Power control wire*
Ground wire*
Battery
4/3/2 CHANNEL AMPLIFIER
4/3/2 CHANNEL
AMPLIFIER
KAC-849
MAXIMUM POWER
KAC-749S
MAXIMUM POWER
Power indicator
KAC-749S
Amplifies only signal input amplifier A with both
amplifiers A and B.
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.
Genuine-accessory
car stereo (No line
output center unit
etc.)
L R
A
L R
B
FILTER OPERATION LINE IN LINE OUT
A.CH B.CH
A.CH B.CH INPUT SELECTOR +
A B A B
OFF OFF MONO(Lch) MONO(Lch) A B A
ON HPF LPF HPF LPF STEREO STEREO
1 1 80 80
150 150 L
100 100 100 100
2 0.5 2 0.5
80 80 GND
3 3
0.3 0.3 150 150
4 4 SPEAKER LEVEL INPUT
(MIN)5 0.2(MAX) (MIN)5 0.2(MAX) 50 LPF 200 50 LPF 200 A
R
50 HPF 200 50 HPF 200
A.CH B.CH
A.CH B.CH B
INPUT SENSITIVITY(V)
FILTER FREQUENCY(Hz)
L R
ACC
Battery
Car fuse box
Bridge
A
4
BRIDGED
POWER IN
SPEAKER
LEFT RIGHT
FUSE(40A) BATT. P.CON OUTPUT
A
B
POWER AMPLIFIER
B
Bridge
Description of markings in the figure.
Left
A
Front left
A L
A R Front right
Right
B
B L Rear left
Rear right
B R
Front
F
Rear
R
* Commercially available
parts