Building a 4cx1000 tetrode hf amplifier

This is a scan of an Eimac article which later appeared in the November 1957 QST Magazine. "A Compact AB1 Kilowatt" amplifier using the Eimac 4cx1000 tube. The zip file contains the pages in pdf and gif formats. Below is a much reduced size gif picture of the first page. Also available here on sonic are the Eimac tube data sheets. It's one of the first (of many to come) amplifier projects which use the 4cx1000 tube.

This Author recomends ("Cabernet with fish") you consider: 1). A screen shunt regulator. 2) Adding tuned input or a terminated balun (or un-un) input. 3) "New generation" parasitic suppressors and detailed amplifier glitch protection as best described by Rich Measures excellent web site. The Collins 30S-1 Amplifier is another great example of this tube in HF service. The diagram for the 30S-1 is also available on sonic. Filament voltage should be kept within a few percent of the nominal voltage for maximum tube life. The grid will quickly go on vacation should you drive it above it's very low max. A hardy large volume blower is also a must have. Boxer fans are often big trouble in forced air ceramic tube cooling applications.


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