An Approach to Audio Frequency Amplifier Design

This volume of seventeen high-quality amplifier designs, covering a range of five through eleven hundred watts, came out of the Research Laboratories of General Electric Company (UK). The research leading to publication included a team of the most distinguished designers of the day. W.I. Heath and D.M. Leakey were joined by G.R. Woodville in putting together what is at once an authoritative and comprehensive compendium of audio amplification hardware.

These designs are all based on vacuum tubes, or as the British prefer to call them, thermionic valves. GEC produced some of the world's finest of these devices, designed especially for audio applications. The KT66 and KT88 were and still are highly regarded wherever tubes were being used to amplify sound. The designs included here cover applications from a simple amplifier for home use to very large units for public address in auditoriums and stadiums.

The book offers more than power amplification, however. Two high- quality, versatile preamplifiers are also included. A simple minimal one offers tape, phono and tuner inputs with only a simple treble cut control in addition to the level control. The second is more sophisticated with bass and treble tone controls, a special tape input, and a variety of phono input networks.

Full parts lists accompany each schematic with specifications allowing today's builder to construct his or her own version of the designs. Full performance measurements of each of the designs are provided, all of which were built as fully operational prototypes. Ratings for all the tubes mentioned are provided in tabular form, including both European and US equivalents, wherever available.

The book is a goldmine of authoritative information delivered in a straightforward, conservative fashion. It provides firm guidance for the tube enthusiast and full explanations of all the important considerations in designing quality amplification.

Key Topics

• LN309 5w push-pull amp
• N709 14w UL push-pull amp
• KT33C 14w push-pull amp
• KT66 Williamson amp
• KT88 30w amp
• KT88 50w amp
• KT55 50w push-pull amp
• DA42 175w push-pull amp
• DA100 200w push-pull amp
• V1505 300w push-pull amp
• pre-amplifier