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English

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.

The speaker cables and sigma servo cables should be distributed along the same paths.

• 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.

2

CAUTION

NOTE

Basic sigma servo connection

Series connection

Make this cable as short as possible.

2

CAUTION

Parallel connection (1)

The speaker cables connected to this unit
should be thick enough to supply the current
capacity of two speakers.

2

CAUTION

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

2

CAUTION

Simplified sigma servo connection

Parallel connection (2)

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.

Summary of Contents for KAC-818

Page 1: ...KAC 818 B64 1355 00 EM MONO POWER AMPLIFIER INSTRUCTION MANUAL ...

Page 2: ... exposed to direct sunlight or excessive heat or humidity Also avoid places with too much dust or the possibility of water splashing When replacing a fuse only use a new one with the prescribed rating Using a fuse with the wrong rating may cause your unit to malfunction To prevent a short circuit when replacing a fuse first disconnect the wiring harness If you experience problems during installati...

Page 3: ...t such as the brake lamps turn signal lamps and windshield wipers operate normally 2CAUTION Installation board etc thickness 15 mm or more Self tapping screw ø4 16 mm 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 t...

Page 4: ... 6 SIGMA SERVO FEED BACK terminals See p 8 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 et...

Page 5: ... 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 s...

Page 6: ...NPUT LEFT RIGHT SPEAKER LEVEL INPUT MONO POWER AMPLIFIER L 25Hz 15Hz INFRASONIC OFF INPUT SENSITIVITY V LPF FREQUENCY Hz GND R LINE IN 0 3 0 5 1 2 3 4 5 0 2 150 100 70 50 200 LEFT RIGHT SPEAKER LEVEL INPUT RCA cable connection CENTER UNIT Cassette receiver CD receiver etc Power control cable Commercially available part RCA cable Commercially available part Do not connect cables and leads to both R...

Page 7: ... 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...

Page 8: ... 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...

Page 9: ... calling service first check the following table for possible problems PROBLEM POSSIBLE CAUSE SOLUTION No sound No sound from one side The output level is too small or too large The sound quality is bad The sound is distorted Input or output cables are disconnected The connection of the sigma servo terminals is wrong Protection circuit may be activated The fuse may be blown because the volume was ...

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