Heater-to-Cathode Voltage (max)Heater-Cathode Voltage (max)100V
Max Grid Resistor
Notes
The 6C4 is electrically one half of a 12AU7 (ECC82). The electrode structure is identical, making it useful as a reference when comparing single vs. dual triode designs.
Plate is connected to both pins 1 and 5 for reduced lead inductance at VHF — both pins must be connected in the circuit.
Pin 2 is an internal connection (internal shield) — do not ground or connect externally unless using an external shield per EIA 316.
Grid-circuit resistance limits differ by bias method: 0.25 MΩ max with fixed bias, 1.0 MΩ max with cathode bias.
First registered May 9, 1942, developed by RCA. Predecessor to this socket type was the 6L5G (octal).
5744 (WA, WB) and 1201 are ruggedized military versions with identical pinout (Brans Vademecum).
Raytheon (1945) lists 6J5GT/G and 6L5G as substitutes — these are octal-base triodes, not pin-compatible with the B7G 6C4.