This tube was designed by Amperex and is listed as a low distortion zero bias Class B Amplifier and Modulator and as a high frequency multiplying power amplifier and conventional power amplifier. It has an amplification factor of 90 and DC plate voltage of 750 - 1000.
Dimensiones (Alt,Ancho,Prof.) incl.pins/tip
x 172 x 54 mm / x 6.77 x 2.13 inch
Literatura
Tube Lore (II) p. 85
Tube Lore (I)
Taschenbuch zum Röhren-Codex 1948/49
Babani, International Radio Tube Encyclopaedia
3C21
Anónimo 10 Coleccionista
Just Qvigstad
3C21: Manufacturer's Literature
Emilio Ciardiello
Mas ...