ABSTRACT
This chapter covers dc regulated power supplies design. DC regulated power supplies play an important role in audio amplifiers. They have direct impact on an amplifier’s sonic performance. This is especially true for low level signal amplification such as line-stage amplifiers and phono-stage amplifiers. The attributes for a good dc regulated power supply include low noise, stabilized line regulation against ac mains variation, loading variation and temperature variation. Most of the dc regulated power supplies discussed in this chapter meet these requirements. Various types of linear dc regulated power supplies are presented. It begins with the basic ac to dc unregulated power supplies by means of half-wave, full-wave rectifications, L-C and R-C filtering. Some commonly used three-terminal dc regulators, including fixed voltage and adjustable voltage types, are covered. They include 78XX, 79XX, LM317, and TL783. Then shunt type and series type regulated power supplies employing discrete solid state devices, vacuum tubes, and a hybrid approach are discussed. Extensive practical design examples are given. The dc regulated voltages in the examples range from ±3.3V, ±15V, ±45V, up to –150V and 350V. Finally, several useful methods of preventing power transformers from producing unwanted noise are also given.
