User manual AUSTRALIAN MONITOR KA1500

[. . . ] PROFESSIONAL AUDIO AMPLIFIER KA1500 Operation Manual Please read carefully. This operation manual contains important information regarding safety precautions, installation, performance, operation and maintenance of your KAKA-Series power amplifier. You should familiarize yourself with the contents of this manual before operating your amplifier. IMPORTANT! Safety Precautions and Labelling The rear panel of the unit has a number of markings and internationally recognized symbols related to the hazards and precautions that should be taken when operating MAINS connected equipment. The presence of a LIGHTNING FLASH with an arrowhead contained within the boundaries of an equilateral triangle is intended to alert the user that dangerous uninsulated voltages may exist within the unit's enclosure. These voltages may be of a sufficient magnitude as to constitute the risk of an electrical shock. [. . . ] While the ICS circuit operates there is also a 30dB mute on the signal input. After two seconds this mute will release, allowing any applied signal to pass unattenuated. When switching the amplifier off, wait a couple of seconds before switching the unit on again. This allows the ICS circuit to reset. Level Matching The normal operating position for the attenuator is the "0 dB" position (fully clockwise, no attenuation). Turning the attenuator back (anticlockwise) reduces the input sensitivity by the amount marked on the attenuator scale (dial). NOTE: If full power output is required you should operate your amplifier with the front panel attenuator above the -15dB position, otherwise clipping of the input circuitry and its resultant distortion will occur before full output power is achieved. Sensitivity Your amplifier is a linear device operating with a fixed input to output voltage gain (less attenuation). The maximum output voltage swing is determined by the applied mains voltage, load, load type and the duty cycle of the applied signal. The input sensitivity for your amplifier when the attenuator is at the "0" dB attenuation position (fully clockwise) is nominally: +4. 0dBu (1. 23 volts in) for rated power into a 8 ohm load. Each channel of your amplifier has a nominal balanced input impedance of 30kOhms (@1kHz) and should Powering Up REMEMBER The amplifier should be the last piece of equipment that you turn on and the first piece of equipment that you turn off. We recommend turning the attenuators on your amplifier down when turning the unit on. When you power up your amplifier, your amplifier goes through an establishment period before it will accept signal. The Inrush Current Supression (ICS) 14 Operation not present a difficult load for any signal source. the equipment feeding the amplifier) should have an output impedance of 600 Ohms or lower to avoid unwanted high frequency loss in the cabling. equipment earth appears to the amplifier's input as a signal and is amplified as hum. Ensure your mains power for the audio system is "quiet" i. e. without equipment on it such as airconditioning, refrigeration or lighting which may generate noise in the earth circuit. Ensure all equipment within the system shares a common ground/ safety earth point. This will reduce the possibility of circulating earth currents as the equipment will be referenced to the same ground potential. Ensure that balanced signal leads going to the amplifier are connected to earth at one end only. Hum Problems Most equipment is designed for minimum hum when used under ideal conditions. When connected to other equipment, and to safety earth in an electrically noisy environment however, problems will often occur. The three "E"s of hum and hum related noise which can plague your audio system are: a) Electrostatic radiation, b) Electromagnetic radiation, and c) Earth loops Electrostatic radiation capacitively couples to system elements causing an interference voltage that mainly affects higher impedance paths, such as amplifier inputs. The source is generally a nearby high voltage such as a mains lead or a speaker lead. [. . . ] Give the main filter capacitors time to discharge before removing lids and inspecting the fuses. When checking for a failed fuse, do not rely on visual inspection alone. Onlycompetent or qualifiedpersons should attempt any service or maintenance of your amplifier. Fans Due to the openness of the air path through your KA1500 amplifier, very little dust should settle within the amplifier. The unit has been designed so that any dust and/or foreign particles that do settle within the amplifier will not unduly hinder the cooling of the unit. The mesh grille in front of the fans will act to limit the amount of dust and lint entering the unit. [. . . ]