Maximum Control Grid VoltageMaximum Control Grid Voltage-100V
Maximum Voltage between g1 and g2Maximum Voltage between g1 and g2400V
Section 2 — Triode Strapped
Absolute Maximum
Anode Voltage (max)Anode Voltage (max)300V
Anode Dissipation (max)Anode Dissipation (max)37W
Cathode Current (max)Cathode Current (max)300mA
Typical Operating
Anode ResistanceAnode Resistance600Ω
Heater
Heater VoltageHeater Voltage6.3V
Heater CurrentHeater Current1.6A
Notes
Anode connects to a top cap (American miniature type), not to a base pin. Requires a top-cap clip lead or adapter.
Originally designed as a voltage regulator series-pass tube for stabilised power supplies, intended for parallel operation of multiple tubes. The datasheet typical operating conditions (Va=Vg2=150V, Ia=200mA) reflect regulator service, not audio use.
Screen grid is limited to 300V maximum — considerably lower than many audio beam tetrodes. In audio circuits, B+ voltages must be chosen carefully to avoid exceeding this rating, especially in cathode-biased designs where screen voltage can rise.
Triode-strapped mu is only 5.5, requiring significant drive voltage. At higher anode voltages (above 300V) the plate curves compress severely and bias voltage becomes very large, making the tube impractical above ~300V in triode mode.
A ruggedised variant, the 12E1R, was also produced.
The 12E1C is listed as an improved successor variant.