This Design Idea is a reprint of an earlier one that contained errors in graphics (Reference 1). Even though 6L6 beam-power tubes have been around for 66 years, they are still quite popular for use in ...

Tube packaged in type 311A cardboard box. 311A crossed out and 310A written in pencil. A pentode with a 6-pin plastic base, top contact, domed glass envelope. Indirectly heated cathode. Heater voltage ...

With both control and screen grids using frame-grid construction, a new pentode boasts performance features that far surpass those available in conventional pentodes. Compared with some of the better ...

A plastic 4-pin base with S-shaped envelope. Donor’s card reads: “Receiving pentode made by Philips of Holland. Used as a Class A power amplifier in the output stage of radio receivers. Output 2.8 ...

Ron Quan, analog aficionado and inventor of the dreaded MacroVision VHS content scrambling system, saw my blog about a radio that uses Russian rod tubes. I saw Ron Saturday at the last eFlea of the ...