This special collection of prime article projects is a clear testimony to the continuing enthusiasm, worldwide, for vacuum tube technology. The majority of those whose work is included here live outside the United States. It is now 14 years since this company launched Glass Audio, a periodical for tube lovers with a penchant for building their own equipment.

Despite the difficulties of dwindling supplies of tubes, rising prices on many of them, and the very slow development of other manufacturing sources in Eastern Europe, Russia, and China, the com- munity of enthusiastic tube project constructors seems to grow steadily.

In 2001 we combined the Glass Audio title into a new magazine, audioXpress, with materials from our other publications, giving special attention to topics covering solid-state equipment and loudspeakers. At that time many were sure that the interests of tube lovers would be neglected and that interest in tubes would suffer.

Quite the opposite has happened. In audioXpress speaker enthusiasts are discovering the wonderful world of tubes, and the solid-state people are seeing possibilities in hybrid circuits, which combine the advantages of solidstate power and voltage control serving the operation of tube circuitry in ways not possible in the earlier history of electronics.

Almost everything in the world of electronic components has changed in the 40 years or so since the beginning of a shift to solid-state topologies. Capacitors are infinitely better, and resistors are quieter, much more precise, and cheaper. Almost every ancillary part in tube designs is better and cheaper today than it was when tubes began to be regarded as obsolete. In short, tubes are sounding better than they ever did. Tube enthusiasts also know that building tube equipment is, in many ways, easier and more fun than solid state. The feeling is much more "hands on" with tubes. Wiring is simpler point- to-point, and the resulting units are easier to modify or repair.

It was with all these facts in mind that we made the decision to put together this really outstanding group of arti- cles by world-class authors. Our thanks to them for their work, their passion, and their clever insights which have made all this material possible. -The Publisher