In 1976, a Soviet fighter pilot named Viktor Belenko made an emergency landing in Hokkaido, Japan. He was flying a MiG-25 supersonic interceptor jet and, upon touching down, requested political asylum. This proved to be a stroke of brilliant luck for the Americans. The MiG-25 remains one of the fastest and highest-flying aircraft ever produced, and Belenko’s defection allowed them to have a tantalizing look at the technology inside.
After the US Air Force took the plane apart piece by piece, the Japanese returned it to the Soviets in 30 containers, charging them $40,000 for crating services. Later, the Soviets sent the Japanese a $10 million bill for missing parts. Both invoices are still outstanding. In the meantime, Belenko became a US citizen through an act of Congress and, after changing his surname to Schmidt and marrying a music teacher from North Dakota, settled in the Midwest and co-wrote a book about his ordeal. He died at age 76 in Rosebud, Illinois, this past September.
Among the top-secret loot found inside the Soviet jet was a large, heavy triode vacuum tube used as a regulator in the power supply of the MiG’s radio. It was known as the 6C33C. (The enormous electromagnetic pulse caused by a nuclear explosion would fry a transistor. Tubes were used in military equipment with such an eventuality in mind.) As it happens, the 6C33C also offers unusual and promising abilities in less dire applications: remarkably high transconductance and current-handling ability combined with very low impedance. This triode can create some serious watts without requiring a heroically large or complex output transformer. In the 1970s and ’80s, the Soviet military complex produced the tube in vast numbers, so new-old-stock examples are still widely available. Perhaps not surprisingly, the audio manufacturers best known for working with
