From Wikipedia, the free encyclopedia
Jump to: navigation, search
Eimac 4-250A beam tetrode power tube

Eimac is a trade mark of Eimac Products, part of the Microwave Power Products Division of Communications & Power Industries. It produces vacuum tubes for radio frequency applications such as broadcast and radar transmitters.


While employed by the small San Francisco, California manufacturing firm of Heintz & Kaufmann, Bill Eitel (amateur radio call sign W6UF) and Jack McCullough (W6CHE) convinced company president Ralph Heintz (W6XBB) to allow them to develop a transmitting tube that could operate at lower voltages than those then available to the amateur radio market, such as the RCA 204A or the 852. Their effort was a success and resulted in production of the HK-354. Shortly after in 1934, Eitel and McCullough left H&K to form Eitel McCullough Corp. in San Bruno California.[1]

The first product produced under the trade mark "Eimac" was the 150T power triode. The new company thrived during World War II by selling tubes to the U.S. military for use in radar equipment.[2]

Beginning in 1947, Eimac operated FM radio station KSBR from their plant in San Bruno, California, one of only two FM stations in the United States to test the new Rangertone tape recorders (adapted from the German Magnetophon recorders).[3] In need of more space, the company moved to San Carlos in 1959. [4] Eimac's San Carlos plant was dedicated on April 16, 1959.[5] In 1965, Eimac merged with Varian Associates and became known as the Eimac Division. In August 1995, Varian Associates sold the Electron Device Business to Leonard Green & Partners, a private equity fund, and members of management. Together, they formed Communications & Power Industries.

In January 2004, affiliates of The Cypress Group, a private equity fund, acquired CPI.

In February 2011, an affiliate of Veritas Capital, a private equity investment firm acquired CPI.



External links[edit]