Noval twin triode with similar mu (16.5 vs 18) and gm (3.1 vs 3.4 mA/V) but 12.6V heater with center-tap vs 6.3V only, and significantly higher Pa_max (3.5W vs 2.0W per section). Pin 9 is heater CT on 12BH7 vs internal screen on 6/30L2.
Heater-to-Cathode Voltage (max)Maximum Heater to Cathode Voltage (RMS)150V
Max Grid ResistorMaximum Grid Resistor0.25MΩ
Typical Operating
Notes
British Mazda designation; the Mullard-system equivalent is ECC804 and the US RETMA equivalent is 6GA8.
Contains an internal electrostatic screen (pin 9) between the two triode sections to reduce inter-section coupling. The potential of the internal shield must not be positive to that of either cathode.
The permissible anode dissipation rating (2.0W per section) is dependent on the grid-to-cathode resistance and the circuit employed. For the values quoted, the grid-to-cathode resistance should not exceed 0.25 MΩ with cathode self bias.
Maximum total anode dissipation (both sections combined) is 2.5W.
Heater-to-cathode voltage max (150V RMS) is measured with respect to the higher potential heater pin.
Datasheet marked 'TENTATIVE' — issued January 1958 by Siemens Edison Swan Limited (Valve & CRT Division).
Pin Layout — Noval
1Anode 2
2Control Grid 2
3Cathode 2
Socket-Compatible Tubes ⚠ Not electrically compatible