valve, tube, thermionic, electron, triode, tetrode, pentode, power, magic eye, tuning indicator, nixie, history, data, data sheet, specification, amplifier, radio, octal, B9A, B7G, B4, IO, KT88, KT66, 12AX7, 12AY7, 12AT7, ECC81, ECC82, ECC83, 6L6, 6V6, EL34, EL84, EM34, EM80, EM81, EM85, Mullard, Cossor, GEC, Gold Lion, Marconi, Svetlana, Brimar, Ferranti, RCA, Sylvania, GE,6202, amperex, arcturus, brimar, channelmaster, colvern, cossor dario, debanks, edicron, ediswan, ei, elpico, emi, emston, era, eratron, ever-ready, ferranti, ge, gec heinz, kaufman, haltron, hivac, hrs, itt, jackson lamba, lorenz, marconi, mazda, mullard, national, osram philips, rank, raphone, raytheon, rca, rft, selectron sovtek, standard, svetlana, sylvania, telefunken, tronix, tungsram united, valvo, westinghouse, zaerix