System examples
L
R
L
R
A
B
A
B
L
R
L
R
A
B
L
R
L
R
A
B
L
R
L
R
A
B
L
R
L
R
A
B
L
R
L
R
A
B
L
R
L
R
!
@
#
F
R
LPF
HPF
OFF
B.CH FILTERA.CH FILTER
LPF
HPF
OFF
@
LPF
HPF
OFF
B.CH FILTERA.CH FILTER
LPF
HPF
OFF
@
LPF
HPF
OFF
B.CH FILTERA.CH FILTER
LPF
HPF
OFF
B.CH OPERATION INPUT SELECTOR
MONO (Lch)
STEREO
A.CH OPERATION
MONO (Lch)
STEREO
A AB
!#
B.CH OPERATION INPUT SELECTOR
MONO (Lch)
STEREO
A.CH OPERATION
MONO (Lch)
STEREO
A AB
!#
B.CH OPERATION INPUT SELECTOR
MONO (Lch)
STEREO
A.CH OPERATION
MONO (Lch)
STEREO
A AB
!#
B.CH OPERATION INPUT SELECTOR
MONO (Lch)
STEREO
A.CH OPERATION
MONO (Lch)
STEREO
A AB
25
432
L
A
A
R
L
R
B
A
B
B
GND
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.

1Fuse (25 A)

2Battery terminal

3Ground terminal

4Power control terminal

5Amplifier 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.)

6INPUT 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
adjusted independently regardless of the position
of the input selector switch.
Use the diagram on the right as a guide.
For the pre-output level or the maximum power
output, refer to the “Specifications” in the
instruction manual of the center unit.

7RCA cable ground lead terminal

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.

8Amplifier A/B LINE IN terminals

9LINE 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.

0Speaker level input terminals

!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.)

@FILTER switch

These switches allow filtering of the speaker
output signals.

HPF (High Pass Filter) position

Only frequencies of 150 Hz or higher are output.
(Frequencies below 150 Hz are cut.)

LPF (Low Pass Filter) position

Only frequencies of 80 Hz or lower are output.
(Frequencies above 80 Hz are cut.)
The Lch and Rch will be mixed before output
even if the operation switch is set to STEREO.

OFF position

The original sound without filtering is 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:

Amplifies only signal input amplifier A with both
amplifiers A and B.
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

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.
2CAUTION
NOTE
Controls
6
0.2(MAX)
(MIN)5
0.3
0.5
1
2
3
4
INPUT SENSITIVITY(V)
25

1 92 3 4 75 0

! #

8

@

6

(W)
30
40
20
10
Power indicator
Terminal cover
Battery
Ground wire*
Battery wire*
Protective Fuse*
Power control wire*

Power wire connection

L
C
C
L
C
C
!@#
L
R
L
R
L
R
L
R
A
B
LPF
HPF
OFF
B.CH FILTERA.CH FILTER
B.CH OPERATION
INPUT SELECTOR
MONO (Lch)
STEREO
A.CH OPERATION
MONO (Lch)
STEREO
LPF
HPF
OFF
A AB
Connection
For safe installation, read "Installation procedure" before starting work.
NOTE
25
25
4
4
LL
A
A
L
A
A
B
R
B
R
LR
RL
R
AR
B
B
L
A
R
L
R
B
L
B
LEFT
BRIDGED
RIGHT
A
B
BRIDGED
RL
LEFT
BRIDGED
RIGHT
A
B
BRIDGED
RL

7

55

GND
CENTER UNIT(Cassette receiver,
CD receiver, etc.)
Power control wire*
RCA cable*
Genuine-accessory
car stereo (No line
output center unit
etc.)
ACC
Battery
Car fuse box
Lead terminal* Lead terminal*

4-channel 4-channel

3-channel

2-channel

2ch + woofer

2-channel

RCA cable connection Speaker level input connection

Speaker stereo connection Speaker bridge connection

CENTER
UNIT
CENTER
UNIT
CENTER
UNIT

2-channel

CENTER
UNIT

Tri-mode

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 ()
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.
2CAUTION
LC
0 dB
-3 dB
Crossover Frequency
Frequency
CENTER
UNIT High pass
Subwoofer
(L + R)
159000
C= (µF)
fc x R
159 x R
L= (mH)
fc
159000
= = 331.25 µF
120Hz x 4
159 x 4
= = 5.3 mH
120Hz
Front left speaker
Front right speaker
Rear left speaker
Rear right speaker
Left speaker
Right speaker
Left speaker
Right speaker
Subwoofer
Lead terminal*
Bridge
Bridge
White
White/Black
Gray
Gray/Black
Green
Green/Black
Purple
Purple/Black
A-channel
A.ch Left
A.ch Right
B-channel
B.ch Left
B.ch Right
Front
Rear
Cable Color of the
connector
F
R
*Commercially available
parts
Description of markings in the figure.
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