User manual KENWOOD KAC-721

[. . . ] 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. [. . . ] · Install this unit in a location which allows heat to easily dissipate. Once installed, do not place any object on top of the unit. · Install the unit securely in a location that does not interfere with driving. 3 Controls Operations of the following control and switches are required in accordance with the center unit and speakers connected with this unit. FUSE(20A) POWER IN BATT 20 GND SERVO P. CON(REMOTE) SPEAKER OUTPUT SERVO FUSE(20A) 20 12 3 4 5 6 SPEAKER LEVEL INPUT LEFT RIGHT 15Hz OFF 25Hz INFRASONIC LPF INPUT FREQUENCY(Hz) SENSITIVITY(V) 100 70 50 200 150 1 2 3 4 0. 5 0. 3 LINE IN L GND R 5 0. 2 MONO POWER AMPLIFIER 7 8 90 ! @ 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 connected with this unit, or to the maximum power output of the genuine-accessory car stereo. 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. 15 10 0. 5 1 2 3 4 0. 3 25 5 (V) 0. 2 (W) 4 0 RCA cable ground lead terminal !LINE IN terminal @ Speaker level input terminals Power indicator s Power indicator: When the power is turned on, the Power indicator lights. Do not turn the power on if the ground cable a fusible link or breaker is not connected. nearby the battery's · When installing two amplifiers, connect a power tune-up cable to positive terminal. each of them while taking care not to exceed the cable capacity. · The power cable should be thick enough to supply the required current and connected directly from the battery. Speaker output cable terminal Connect the speaker output cables to these terminals. Lead terminal (Commercially available part) Speaker output cable Power terminal Pass battery and ground cables through supplied terminal cover and connect to respective terminals. After completing connections, fasten terminal cover over terminal bracket. Round terminal (Medium) Round terminal (Small) 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. [. . . ] · Protection circuit may be activated. · The fuse may be blown because the volume was too high. The input sensitivity adjusting control is not set to the correct position. · The speakers cable are connected with wrong + / polarity. [. . . ]