Kenwood Stereo Amplifier KAC 648 User Manual

KAC-648  
4-CHANNEL POWER AMPLIFIER  
INSTRUCTION MANUAL  
B64-1364-00 (EM)  
 
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 speaker cables.  
5.Connect the power cable, power control cable and grounding cable following this order.  
6.Install the unit in the car.  
7.Connect the negative - terminal of the battery.  
2CAUTION  
• Be sure to turn the power off before changing the setting of any switch.  
• If the fuse blows, check cables 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 cables to appropriate speaker connectors separately. Sharing the negative  
cable of the speaker or grounding speaker cables 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.  
Installation  
Self-tapping screw  
Installation board, etc.  
(thickness : 15 mm or more)  
• 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.  
• Use the extension cables. (Optional.)  
Length  
0.5m  
1m  
2m  
4m  
5m  
6m  
Type  
RCA cable  
RCA cable (ø7mm)  
RCA cable (ø12mm)  
CA-2SL  
CA-12SL CA-22SL  
CA-52SL  
CA-53WL  
CA-3WL CA-13WL CA-23WL  
CA-5W CA-15W CA-25W  
CA-45W  
CA-65W  
2CAUTION  
• 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.  
3
 
Controls  
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.  
5
SPEAKER LEVEL INPUT  
BRIDGED  
LEFT  
SPEAKER OUTPUT  
A
POWER IN  
FUSE(25A)  
LEFT  
RIGHT  
RIGHT  
A
B
GND  
SPEAKER LEVEL INPUT  
BATT  
P.CON(REMOTE)  
A
B
L
R
B
1
2 3 4  
6
7
8
9
0 !  
FILTER  
OFF  
LPF  
OPERATION  
(Lch)  
MONO  
FILTER  
OFF  
OPERATION  
INPUT SELECTOR  
LINE IN  
LINE OUT  
A
B
A
A
B
A
+
B
STEREO  
MONO(Lch)  
STEREO  
HPF  
LPF  
HPF  
1.0  
1.0  
0.5  
MONO  
L
L
0.5  
0.3  
GND  
0.3  
MIN  
MAX  
MIN  
INPUT  
SENSITIVITY(V)  
MAX  
4 CHANNEL  
POWER AMPLIFIER  
INPUT  
SENSITIVITY(V)  
R
R
CONTROL  
A
CONTROL  
B
@
mA  
mA  
#
$
%
When multiple speakers are to be  
connected, ensure that the combined  
impedance is 4or greater.  
1 Fuse (25 A × 1)  
2 Battery terminal  
3 Ground terminal  
2CAUTION  
4 Power control (REMOTE) terminal  
The rated input of the speakers should be  
no less than the maximum output of the  
amplifier. Otherwise malfunction may  
result.  
5 Amplifier A speaker output  
terminals  
6 Amplifier B speaker output  
7 Speaker level input terminals  
terminals  
8 INPUT SELECTOR switch  
This switch selects the input method of the  
signals to be amplified by amplifiers A and  
B.  
SPEAKER OUTPUT terminals  
• Stereo Connections:  
When you wish to use the unit as a stereo  
amplifier, stereo connections are used.  
The speakers to be connected should have  
an impedance of 2or greater. When  
multiple speakers are to be connected,  
ensure that the combined impedance is 2Ω  
or greater for each channel.  
A
B
A
INPUT SELECTOR  
• A B position:  
Amplifies both of the signals input to  
amplifiers A and B.  
• A position:  
Amplifies only signal input amplifier A with  
both amplifiers A and B.  
• 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.)  
The speakers to be connected should  
have an impedance of 4or greater.  
9 Amplifier A LINE IN terminal  
0 Amplifier B LINE IN terminal  
4
 
independently according to the setting of  
this switch.  
• STEREO position:  
The amplifier can be used as a stereo  
amplifier.  
! 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.  
• MONO (Lch) position:  
@ RCA cable ground lead terminal  
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 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.  
% FILTER switch  
The sensitivities of amplifiers A and B can  
be adjusted independently regardless of the  
position of the input selector switch.  
These switches allow filtering of the  
speaker output signals.  
• HPF(High Pass Filter) position:  
Only frequencies of 150Hz or higher are  
output. (Frequencies below 150Hz are cut.)  
• LPF(Low Pass Filter) position:  
Only frequencies of 80Hz or lower are  
output. (Frequencies above 80Hz are cut.)  
The Lch and Rch will be mixed before  
output even if the operation switch is set to  
STEREO.  
Use the diagram on  
15  
10  
1.0  
the right as a guide.  
1.0  
0.5  
2.0  
3.0  
0.5  
0.3  
0.3  
MAX  
MIN  
(V)  
25  
4.0  
(W)  
0.2  
NOTE  
For the pre-output level or the maximum  
power output, refer to the “Specifications”  
in the instruction manual of the center unit.  
• OFF position:  
The original sound without filtering is  
output.  
$ OPERATION switch  
The amplification methods of the signals  
input to amplifiers A and B can be selected  
System examples  
Full-range 4-channel + Subwoofer system  
1.0  
0.5  
L
L
Front  
FILTER  
OPERATION  
STEREO MONO(Lch)  
LPF  
A
B
OFF  
R
HPF  
0.3  
MAX  
INPUT  
SENSITIVITY(V)  
speaker  
R
CENTER UNIT  
Switch setting  
MIN  
INPUT SELECTOR  
CONTROL  
CONTROL  
A
B
L
A
B
A
L
1.0  
0.5  
Rear  
speaker  
R
FILTER  
OFF  
OPERATION  
(Lch)  
MONO  
HPF  
LPF  
R
STEREO  
0.3  
L
LINE  
OUT  
MIN  
INPUT  
SENSITIVITY(V)  
MAX  
R
L
Subwoofer  
R
Power amplifier  
5
 
System examples  
High-pass + Subwoofer system  
1.0  
0.5  
L
L
FILTER  
OFF  
OPERATION  
STEREO MONO(Lch)  
A
B
(High pass)  
HPF  
LPF  
R
0.3  
MAX  
INPUT  
SENSITIVITY(V)  
MIN  
R
CENTER UNIT  
Switch setting  
INPUT SELECTOR  
CONTROL  
CONTROL  
A
B
L
A
B
A
1.0  
0.5  
R
Subwoofer  
(L + R)  
(Bridged)  
FILTER  
OFF  
OPERATION  
(Lch)  
MONO  
HPF  
LPF  
STEREO  
0.3  
L
LINE  
OUT  
MIN  
INPUT  
SENSITIVITY(V)  
MAX  
R
High-power 2-channel system  
1.0  
0.5  
L
L
Left  
FILTER  
OFF  
OPERATION  
STEREO MONO(Lch)  
A
B
HPF  
LPF  
R
0.3  
MAX  
INPUT  
SENSITIVITY(V)  
CENTER UNIT  
Switch setting  
speaker  
MIN  
INPUT SELECTOR  
CONTROL  
CONTROL  
A
B
L
A
B
A
R
1.0  
0.5  
Right  
speaker  
R
FILTER  
OFF  
OPERATION  
(Lch)  
HPF  
LPF  
STEREO  
MONO  
0.3  
L
LINE  
OUT  
MIN  
MAX  
INPUT  
SENSITIVITY(V)  
R
Tri-mode  
(High pass)  
L
L
C
C
1.0  
0.5  
FILTER  
OFF  
HPF LPF  
OPERATION  
L
L
STEREO  
MONO(Lch)  
A
B
0.3  
R
MIN  
MAX  
CENTER UNIT  
Switch setting  
R
INPUT  
SENSITIVITY(V)  
INPUT SELECTOR  
CONTROL  
CONTROL  
A
B
A
B
A
L
1.0  
0.5  
FILTER  
OFF  
OPERATION  
R
(Lch)  
MONO  
HPF  
LPF  
STEREO  
0.3  
L
MIN  
INPUT  
SENSITIVITY(V)  
MAX  
L
LINE  
OUT  
R
R
Subwoofer  
(L + R) (Bridged)  
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  
Crossover Frequency  
frequencies. (Low pass)  
0 dB  
Capacitor (C): Passes high frequencies and blocks low  
-3 dB  
frequencies. (High pass)  
159000  
L
C
C=  
L=  
(µF)  
fc=Cut of Frequency (Hz)  
fc x R  
159 x R  
fc  
R=Speaker Impedance ()  
Frequency  
(mH)  
Example:  
When it is required to set a crossover frequency of 120 Hz using speakers with an  
impedance of 4 ohms.  
Prepare commercially-available coil and capacitor with the closest ratings to the results  
calculated from the formula above. The capacitor rating should be as close as possible to 331.25  
(µF) and the coil rating should be as close as possible to 5.3 (mH).  
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.  
6
 
Connection  
Power cable connection  
2WARNING  
To prevent fire caused by a short in the wiring, connect a fusible link or breaker nearby the battery’s  
positive terminal.  
SPEAKER LEVEL INPUT  
BRIDGED  
LEFT  
SPEAKER OUTPUT  
A
POWER IN  
FUSE(25A)  
LEFT  
RIGHT  
RIGHT  
A
B
GND  
SPEAKER LEVEL INPUT  
BATT  
P.CON(REMOTE)  
A
B
L
R
B
Round terminal (Small)  
Round terminal (Medium)  
Power terminal  
Terminal cover  
Battery cable  
Power control cable  
Ground cable  
CENTER UNIT  
Round terminal (Large)  
Protective  
Fuse  
Battery  
Power terminal  
Connect to their respective terminals the power control cable, power supply cable, and ground  
cable, all of which pass through the associated terminal cover. Once the connections are  
complete, place the cover on the terminal section.  
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 cable.  
• Do not allow the cord to directly contact the edge of the iron plate by using Grommets.  
• Connect the ground cable 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  
cable is not connected.  
• Be sure to attach a protective fuse into the battery cable 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 cable for the battery cable and the ground  
cable. The current capacity of the power supply wiring cable 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 cable and  
protective fuse of greater current-handling capacity than the total maximum current drawn by each  
amplifier.  
Example: One Power Amplifier Is Used  
Model  
Maximum Current  
Drawn  
Protective Fuse  
Cross-sectional Area of Wiring  
Cable (AWG)  
3 mm (AWG 12) or greater × 1  
2
KAC-648  
22 A  
30 A × 1 [15 A × 2]  
15 A  
15 A  
30 A  
15 A  
15 A  
7
 
Connection  
Speakers cable connection  
(Stereo Connections)  
Front Left speaker  
Front Right speaker  
Lead terminal  
(Commercially  
available parts)  
T
H
IG  
R
BRIDGED  
T
F
E
L
A Right output  
A Left output  
SPEAKER LEVEL INPUT  
LEFT RIGHT  
BRIDGED  
LEFT  
SPEAKER OUTP
A
POWER IN  
FUSE(25A)  
RIGHT  
A
B
GND  
SPEAKER LEVEL INPUT  
BATT  
P.CON(REMOTE)  
B
L
R
B
Speaker terminal polarity  
BRIDGED  
B Right output  
A
B
B Left output  
L
R
Rear Right speaker  
Rear Left speaker  
(Bridged Connections)  
Lead terminal  
(Commercially  
available parts)  
Speaker (Bridged)  
T
H
IG  
R
BRIDGED  
T
F
E
L
A Bridged output  
SPEAKER LEVEL INPUT  
LEFT RIGHT  
BRIDGED  
LEFT  
SPEAKER OUTPUT  
A
POWER IN  
FUSE(25A)  
RIGHT  
A
B
GND  
SPEAKER LEVEL INPUT  
BATT  
P.CON(REMOTE)  
B
L
R
B
Speaker terminal polarity  
BRIDGED  
A
B
B Bridged output  
L
R
Speaker (Bridged)  
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.  
• The impedance of the speakers that are going to be connected should be 2or greater (for  
stereo connections), or 4or 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.  
8
 
Examples:  
Model  
Stereo Connections (4)  
Bridged Connections (4)  
KAC-648  
50 W or greater  
140 W or greater  
50W  
(2)  
25W  
50W  
25W  
(8)  
50W  
(4)  
50W  
50W  
(4)  
(8)  
(4)  
(4)  
50W  
(2)  
4  
4 Ω  
4 Ω  
Maximum output of  
the amplifier  
Combined  
impedance  
Rated input power and  
impedance of the speakers  
RCA cable connection  
2CAUTION  
Do not connect cables and leads to both RCA cable input jacks and the speaker input terminals  
simultaneously, for this may cause malfunction or damage.  
B Left input  
A Left input  
RCA cable ground terminal  
D
N
OPERATION  
FILTER  
OFF  
LPF  
G
FILTER  
OFF  
OPERATION  
STEREO MONO(Lch)  
INPUT SELECTOR  
LINE IN  
LINE OUT  
(Lch)  
A
B
A
A
B
A
+
B
STEREO  
MONO  
HPF  
LPF  
HPF  
1.0  
1.0  
0.5  
MONO  
L
L
0.5  
0.3  
GND  
0.3  
MIN  
MAX  
MIN  
INPUT  
SENSITIVITY(V)  
MAX  
4 CHANNEL  
POWER AMPLIFIER  
INPUT  
SENSITIVITY(V)  
R
R
CONTROL  
A
CONTROL  
B
B Right input  
A Right input  
RCA cable  
(Commercially available part)  
To Power control  
(REMOTE) terminal  
Front output  
Rear output  
CENTER UNIT  
(Cassette receiver,  
CD receiver, etc.)  
RCA cable ground 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
 
Connection  
Speaker level input connection  
Connect the unit by inserting it in the connection between the genuine-accessory car stereo  
and speakers.  
2CAUTION  
Do not connect cables and leads to both RCA cable input jacks and the speaker input terminals  
simultaneously, for this may cause malfunction or damage.  
To Power control  
(REMOTE) terminal  
A Left input  
A Right input  
SPAKER LEVEL INPT  
LEFT IGHT  
BRIDGED  
LEFT  
SPEAKER OUTPUT  
A
POWER IN  
FUSE(25A)  
RIGHT  
A
B
GND  
SPEAKER LEVEL INPUT  
BATT  
P.CON(REMOTE)  
A
B
L
R
B
ACC  
B Right input  
T
H
IG  
R
Car fuse  
box  
B Left input  
Front Right  
Battery  
T
F
SPEAKER LEVEL INPUT  
LE  
Front Left  
Rear Left  
Rear Right  
Genuine-accessory  
car stereo  
Lead terminal  
(Commercially available parts)  
2CAUTION  
• The genuine-accessory car stereo shall have a maximum power output of no more than 25 W.  
• Do not connect the speaker output leads from a power amplifier (Optional) to the speaker input  
terminals of this unit, 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.  
10  
 
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 "Protection function".  
• The fuse may be blown because • Replace the fuse with a new  
the volume was too high.  
fuse and use a lower volume.  
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 cable are  
connected with wrong + / -  
polarity.  
• Connect them properly checking  
the + / - of the terminals and  
cables well.  
• A speaker cable is pinched by a • Connect the speaker cable again  
screw in the car body.  
so that it is not pinched by  
anything.  
• The switches may be set  
improperly.  
• Set switches properly by  
referring to "System examples".  
11  
 
Specifications  
Specifications subject to change without notice.  
Audio Section  
Max Power Output (4 )  
4 Channel Mode.................................................................................................................50 W × 4  
3 Channel Mode............................................................................................50 W × 2 + 140 W × 1  
2 Channel Mode...............................................................................................................140 W × 2  
Rated Power Output (4 )  
4 Channel Mode ..........................................................................25 W × 4 (DIN45324, +B=14.4 V)  
3 Channel Mode ............................25 W × 2 (1 kHz, 0.08 % THD) + 70 W × 1 (1 kHz, 0.8 % THD)  
2 Channel Mode.................................................................................70 W × 2 (1 kHz, 0.8 % THD)  
Rated Power Output (2 )  
4 Channel Mode.................................................................................35 W × 4 (1 kHz, 0.8 % THD)  
Frequency Response ...............................................................................10 Hz ~ 45 kHz (+0, –1 dB)  
Signal to Noise Ratio................................................................................................................100 dB  
Sensitivity (MAX) .................................................................................................0.2 V (rated output)  
Sensitivity (MIN) ..................................................................................................4.0 V (rated output)  
Input Impedance........................................................................................................................10 kΩ  
Low Pass Filter .......................................................................................................80 Hz (12 dB/oct.)  
High Pass Filter.....................................................................................................150 Hz (12 dB/oct.)  
General  
Operating Voltage...................................................................................14.4 V (11 ~ 16 V allowable)  
Current Consumption ....................................................................................22 A (1 kHz, 10% THD)  
Dimensions (W × H × D) ...................................................................................260 × 56.5 × 209 mm  
Weight.......................................................................................................................................3.0 kg  
12  
 

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