Now £5 - Was £10.00
As demand for vacuum tubes waned inevitably in the 1970s due in large part to the advances in semiconductor technology. General Electric UK's fabled lab and production plant began to scale back operations. Three sets of data sheets and two sets of amplifier design information on the famous KT series of power valves were issued separately in simple pamphlet form in the late seventies. We have, with the help of the venerable and equally fabled Sowter Transformer Co. ofEastAnglia, brought these together here under one cover for the convenience of tube and valve aficionados worldwide. This second edition contains KT77 amplifier diagrams and an extensive preamplifier section thanks to the generosity of Kevin F. Gallimore.
GEC had earned an enviable reputation for very high quality products, built to perform at levels rarely achieved by other manufacturers. The KT66 and KT88 valves were probably the most highly regarded pairs of their time during the heyday of quality sound reproduction after WWIL These achievements were no accident. As detailed in an earlier 1957 publication by GECl, W. I. Heath and D. M. Leakey ofGECs Research Labs and G. R. Woodville in the Applications Lab ofM-0 Valve Co., Ltd., a GEC subsidiary, were the chief agents in devel-oping these splendid devices.
The circuit diagrams utilizing the KT66, KT77, and KT88 valves arc the lat-est, and presumably the most authoritative, suggestions by the GEC group. Since their publication, all the associated components used with the valves have gen-erally improved in precision and quality, and in many cases with relatively lower prices. New technologies in plastics and chemicals have improved capacitors and both the ferrous and wire components of transformers. These, along with power rectification and filtering, should make these designs all the morc effec-tive 30 years later.
ABOUT THIS BOOK by Audio Amateur Press
Responding to many requests for data and design information about what are among the most highly regarded audio power tubes in the world, we are presenting in this little volume all the data and design information we were able to assemble to respond to this need. The KT66, KT77 and KT88 power beam tetrodes are unique as a dedicated set of valves optimized for audio use.
With the surprising resurgence of interest in vacuum tube (valves to many) technology, accurate information about the use of these devices is crucial. Stocks of these devices are, of course, very limited. Quantities of them are discovered, from time to time however, in warehouses and private stocks.
The M-0 Valve division of GEC no longer exists, so queries about the information herein is not available. Those enthusiasts fortunate enough to own samples of any of these three types of power tubes will now have the necessary data to care for them and authoritative guidelines for servicing and upgrading equipment which uses them. Audio Amateur Press Peterborough, New Hampshire, September, 2000