KAC-818
MONO POWER AMPLIFIER
INSTRUCTION MANUAL
© B64-1355-00 (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 center unit and this unit according to the required application.
5.Connect the speaker cables and sigma servo feed back cables.
6.Connect the power cable, power control cable and grounding cable 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.
2CAUTION
• 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 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
(ø4 ×16 mm)
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.
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.
English 3
Controls
Operations of the following control and switches are required in accordance with the center
unit and speakers connected with this unit.
POWER IN
FUSE(20A)
∑
∑
SERVO ΙΙ
SERVO ΙΙ
SPEAKER OUTPUT
BATT
GND
20
P.CON(REMOTE)
FUSE(20A)
20
4
5
6
1 2 3
SPEAKER LEVEL INPUT
15Hz
LPF
INPUT
OFF
25Hz
LEFT
RIGHT
LINE IN
FREQUENCY(Hz) SENSITIVITY(V)
0.5
R
L
150
INFRASONIC
100
0.3
1
GND
70
2
MONO
POWER AMPLIFIER
3
4
50
200
5
0.2
7
8 9 0 !
@
1 FUSE (20 A ×2)
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.
6 SIGMA SERVO FEED BACK terminals (See p.8)
2CAUTION
Be sure to make proper connections to the SIGMA SERVO FEED BACK terminals. Incorrect
connection may result in lack of sound output or other malfunctions.
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, 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.
8 LOW PASS FILTER FREQUENCY control
This control adjusts the frequency band output from this unit.
9 INPUT SENSITIVITY control
Set this control according to the pre-output level of the center unit
10
connected with this unit, or to the maximum power output of the genuine-
0.5
accessory car stereo.
Use the diagram on the right as a guide.
15
0.3
1
2
3
4
0.2
25
5
(V)
(W)
4 English
NOTE
For the pre-output level or the maximum power output, refer to the “Specifications” in the
instruction manual of the center unit.
0 RCA cable ground lead terminal
! LINE IN terminal
@ Speaker level input terminals
Power indicator
■ 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.
Power indicator
■ 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.
• A speaker cable may be short-circuited.
• A speaker output may be in contact with the ground.
• The temperature of the internal parts may be higher than 120°C (248°F).
• 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 cable 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 cable may not be connected to this unit.
• The grounding cable of the center 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.
English 5
Connection
■ RCA cable connection
2CAUTION
Left output (White)
Right output (Red)
CENTER UNIT
(Cassette receiver,
CD receiver, etc.)
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.
RCA cable
(Commercially
available part)
Power control cable
(Commercially
available part)
Right input
Left input
SPEAKER LEVEL INPUT
LEFT RIGHT
15Hz
OFF 25Hz
LPF
INPUT
LINE IN
FREQUENCY(Hz) SENSITIVITY(V)
0.5
R
150
INFRASONIC
100
0.3
1
GND
70
2
MONO
POWER AMPLIFIER
3
4
50
200
5
0.2
RCA cable ground terminal
2CAUTION
D
N
G
When using an RCA cable with
a ground lead attached, connect
the ground lead to this terminal.
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.
■ Speaker level input connection
Left output
Genuine-accessory
car stereo
ACC
Right output
Car fuse
box
Lead terminal
T
H
IG
R
(Commercially
available part)
SPEALEKFTER LEVEL INPUT
+
-
Battey
Left input
Right input
SPAKER LEVL INPT
LEFT RIGHT
15Hz
OFF 25Hz
LPF
INPUT
LINE IN
FREQUENCY(Hz) SENSITIVITY(V)
0.5
R
L
150
INFRASONIC
100
0.3
1
GND
70
2
MONO
POWER AMPLIFIER
3
4
50
200
5
0.2
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.
• 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.
• 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.
6 English
■ Power and Speakers cable connection
Distribute the speaker cables and sigma
servo cables along the same paths.
Subwoofer
Round terminal (Small)
Power control cable
(Commercially available part)
POWER IN
FUSE(20A)
∑
∑
∑SERVO ΙΙ
SERVO ΙΙ
∑SERVO ΙΙ
SERVO ΙΙ
SPEAKER OUPUT
SPEAKER OUPUT
BATT
GND
20
P.CO(REMOTE)
FUSE(20A)
20
Power control (REMOTE) lead terminal
Round terminal (Medium)
Terminal cover
Battery cable
(Commercially available part)
Ground cable (Commercially available part)
Round terminal (Large)
Protective
Fuse
+
-
Battery
2WARNING
To prevent fire caused by a short in the wiring, connect a fusible link or breaker nearby the battery’s
positive terminal.
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 cord 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.
Power terminal
Connect to their respective terminals the power control wire, 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.
Example: One Power Amplifier Is Used
Maximum Current Drawn
Protective Fuse
28 A
40 A ×1 [20 A ×2]
25 A
25 A
2
Cross-sectional Area of Wiring
5 mm (AWG 10) or
50 A
25 A
25 A
Wire (AWG)
greater ×1
English 7
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 cables and sigma servo cables 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.
■ Basic sigma servo connection
■ Series connection
2CAUTION
Make this cable as short as possible.
■ Parallel connection (1)
■ Parallel connection (2)
2CAUTION
2CAUTION
The speaker cables connected to this unit
should be thick enough to supply the current
capacity of two speakers.
This connection is possible only when the
speakers are identical and the speaker cables
are also of the same type and length.
■ 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.
8 English
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.
• The connection of the sigma
servo terminals is wrong.
• Protection circuit may be
activated.
• The fuse may be blown
because the volume was too
high.
• Check the connection referring
to "Sigma servo feed back".
• Check connections by referring
to "Power indicator".
• Replace the fuse with a new
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 "Controls".
Specifications
Specifications subject to change without notice.
Audio Section
Max Power Output (2 Ω)..................................................................................................400 W ×1
Rated Power Output
(4 Ω) ......................................................................................200 W ×1 (DIN45324, +B=14.4V)
(2 Ω) ..........................................................................................300 W ×1 (100 Hz, 0.8 % THD)
Frequency Response (+0, –1 dB) ............................................................................5 Hz ~ 200 Hz
#
Total Harmonic Distortion (Rated power) ..............................................................0.01 % (100 Hz)
Sensitivity (rated output) (MAX) ..............................................................................................0.2 V
Sensitivity (rated output) (MIN) ..............................................................................................5.0 V
Signal to Noise Ratio............................................................................................................100 dB
Input Impedance....................................................................................................................10 kΩ
Damping Factor..............................................................................More than 9900 (at ∑ connect)
Low Pass Filter Frequency (24 dB/oct.)........................................................50 ~ 200 Hz (variable)
Infrasonic Filter Frequency (24 dB/oct.) ..........................................................................15 / 25 Hz
# Sensitivity = Mini. , Through LPF (30 kHz)
General
Operating Voltage ................................................................................14.4 V (11 ~ 16 V allowable)
Current Consumption (4 Ω, 14.4 V, 10% THD) ........................................................................28 A
Dimensions (W ×H ×D)......................................................................................290 ×56 ×230 mm
Weight ..................................................................................................................................3.7 kg
English 9
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