Hollow-State Electronics: The Orange Valve Tester MKII

The Orange Valve Tester MKII is a new microprocessor-controlled testing system from the famous British guitar amplification manufacturer. Featuring greatly improved algorithms with an updated database containing the test results of literally hundreds of new, used, and faulty valves, this MKII tester requires no knowledge of valve theory. A user simply inserts a valve into the correct socket, selects the valve type from the list, and presses the ‘OK’ button. The status of the valve under test is quickly revealed.

Richard Honeycutt reviews the second and more extensive edition of this electronics classic, Fundamental Amplifier Techniques with Electron Tubes. He gives high marks to this massive tome that provides useful information about electron tube technology, including their power supplies, for the design and DIY construction of these electron tube audio amplifiers.

Where do tubes come from? In this article Richard Honeycutt revisits the history of tube electronics, from its early invention to the widespread adoption in radios and television receivers. And because familiarity simplifies tube selection, the article explains where some of the most common tube types can be applied in todays designs on power amplifiers and pre-amplifiers and tube stages. This article was originally published in audioXpress, April 2013 as part of the Hollow-State Electronics monthly column by Richard Honeycutt.