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
Marconi Osram MS4B
A pristine example of this early indirectly heated
A.C. pentode on a B5 base. Very similar to the AC/SG or S4VA