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
Tungsram P415
Tungsram P415 four volt triode
Tungsram P415
Tungsram Hungary, "Barium Tube" possibly
using the Azide process? Has a 4 volt filament, probably very
similar otherwise to the P215.