Basic components

Chapter Basic components

Teach Yourself Electricity and Electronics Third Edition Book
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Teach Yourself Electricity and Electronics Third Edition Book

  • amplification stages. In tape recording, there is also some tape hiss. A scheme calledDolby (a trademark of Dolby Laboratories) is used in professional recording studios,and also in high-end consumer tape equipment, to minimize this hiss. Digital recordingtechniques, such as is used in compact disk (CD) or digital audio tape (DAT) recording,have less internal noise than older analog systems.At high volume levels, the power-handling capability of an audio amplifier limits thedynamic range. If all other factors are equal, a 100-watt system will have greater dy-namic range than a 50-watt system. The speaker size is also important; the larger thespeakers, the greater the dynamic range. This is why serious audio enthusiasts some-times purchase sound systems with amplifiers and speakers that seem unnecessarilylarge. The reason for such overengineering is usually twofold: (1) to ensure that thesound peaks will always be distortion-free and cannot possibly damage the speakersand (2) to impress people.Basic ComponentsThere are myriad ways to set up a hi-fi system. Almost every true audiophile (liter-ally, “sound lover”) builds a system over a period of time, component by component.Some people own two or three stereo systems. Here are some basic considerations.ConfigurationThe simplest home stereo system is contained in a single box, with an AM/FM radioreceiver, a tape player, and a CD player. The speakers are generally external. The as-sets of a so-called compact hi-fi system are small size and low cost.More sophisticated hi-fi systems have separate boxes for the radio receiver, thetape player, the CD player, and, in some cases, a turntable, a computer, or other non-standard peripheral. The units in such a component hi-fi system are interconnectedwith shielded cables. This allows you to choose each unit to suit your own taste andneeds. A typical component system costs several times as much as a compact system,but the sound quality is better, and you can have high-power audio.Some hi-fi manufacturers build all their equipment cabinets to a standard width sothey can be mounted one above the other in a rack. A rack hi-fi system has an appear-ance reminiscent of military hardware. This scheme saves floor space and makes thesystem look professional. The rack can be mounted on wheels so the whole system (ex-cept for the external speakers) can be rolled from place to place.Figure 31-4 is a block diagram of a typical home stereo hi-fi system. The amplifierchassis should be grounded to minimize hum and noise and to reduce the system’s sus-ceptibility to electromagnetic interference (EMI). The AM antenna is typically a loop-stick built into the cabinet or mounted on the rear panel. The FM antenna can be anindoor type, such as television “rabbit ears,” or a sophisticated outdoor antenna. If anoutdoor antenna is used, lightning safety precautions must be observed.The tunerA tuner is a radio receiver, usually capable of receiving signals in the standard AMbroadcast band (535 to 1605 kHz) and the standard FM broadcast band (88 to 108Basic components589