6F6

Power Pentode — Octal

RCA

Known Equivalents & Substitutes

6F6-G6F6-GT422A5CV1076VT-66161116136F6MGCV191212C

Similar Tubes (Not Drop-In Compatible)

6F6S

Soviet equivalent (6Ф6С) of 6F6GT — same electrical characteristics but verify pin compatibility

6K6GT

Same octal base and pinout, similar power pentode but lower Pa_max (8.5W vs 10.5W) and slightly different characteristics

Electrical Specifications

Section 1 — Pentode

Absolute Maximum

Anode Voltage (max)Anode Voltage (max)375V

Screen Voltage (max)Screen Voltage (max)285V

Anode Dissipation (max)Anode Dissipation (max)10.5W

Screen Dissipation (max)Screen Dissipation (max)3.5W

Notes

Electrically identical to type 42 (6-pin base) and type 2A5 (6-pin base, 2.5 V heater) except for heater ratings and base.
Grid-No.1 circuit resistance: 0.1 MΩ max for fixed-bias, 0.5 MΩ max for cathode-bias.
The 6F6-G (ST glass) and 6F6-GT (tubular glass) envelopes have identical electrical ratings to the metal 6F6.
RCA AN-52 (1935) documents Class AB push-pull triode connection of type 6F6, achieving up to 18.8 W output.

Pin Layout — Octal

1No Connection (shell on metal type)

2Heater

3Anode (Plate)

4

Socket-Compatible Tubes ⚠ Not electrically compatible

References