Klein + HummelOperating Manual KPA Series English 5■ IntroductionThank-you for purchasing a Klein + Hummel KPA amplifier. Klein + Hummel amplifiers are designed to complimentKlein + Hummel’s extensive range of Installed Sound equipment. No other amplifiers come close for applicationsdemanding high power and long term reliability. Thanks to amazing reductions in heat output along withreductions in weight and the specific high output power, KPA amplifiers can be used in an unlimited range ofapplications such as concert touring, opera houses, theatres, churches, cinema, theme parks, television soundstages and industrial applications.The KPA series amplifiers are fully compatible with all K8 digital audio distribution system input devices and maybe used to simply and easily create the highest quality, low noise audio connection without knowledge ofnetworking techniques.Before reading the rest of this operating manual, review the safety and warnings. Note that imperial dimensionsare approximate.Package ContentsThe shipping carton contains:• This operating manual• The amplifier• Product guarantee• 1 mains power cable (wire ends)Features and accessories are listed at the end of this operating manual.More sound and less weightCompared to a conventional amplifier, Klein + Hummel KPA technology offers very high efficiency and deliversmore power to the loudspeakers with much reduced heat dissipation. This greater efficiency enables dimensions,weight and power consumption to be reduced. The output stages of the amplifiers typically run at 95% efficiency,dissipating only 5% of the input energy as heat.One of the most interesting characteristics is that KPA’s efficiency is almost independent of output level.Conventional amplifiers achieve their best efficiency only at full rated power output. Since standard music has anaverage power density of 40% of the maximum level, conventional amplifiers can easily generate 10 times moreheat than KPA for the same volume of sound.Superior Sound-Sonic AccuracyCrystal-clear highs, and a tight, well-defined low end: the most accurate reproduction of an audio signal. Patenteddesign features ensure very high performance in parameters such as distortion, frequency response, slew rate,power bandwidth and dumping factor.Totally Digital with High ReliabilityThe KPA series is based on PWM technology that has been used for 30 years or more in power supplies andinverters. PWM provides high reliability, small size, low weight and high efficiency. A PWM converter works as ahigh frequency sampler, converting the variable amplitude (audio) signal into an impulse sequence with averagevalue equal to the audio input.KPA amplifiers use very high sampling frequencies to obtain high performances across the audio band.