25L6GT

Beam Tetrode — Octal

Data: HighHigh quality — base, heater, all universal parameters present, and ≥50% of desirable parameters filled in. Safe to use for design decisions.

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Known Equivalents & Substitutes

25L625L6GVT-201

Similar Tubes (Not Drop-In Compatible)

12W6GT

Electrically identical but 12.6V/0.6A heater — not a drop-in substitute

6V6

Similar beam tetrode but different electrical characteristics (lower gm, different bias point) and 6.3V heater

6W6

Electrically identical but 6.3V/1.2A heater — not a drop-in in 25V series heater circuits

Electrical Specifications

Section 1 — Beam Tetrode

Absolute Maximum

Anode Voltage (max)Anode Voltage (max)330V

Screen Voltage (max)Screen Voltage (max)165V

Anode Dissipation (max)Anode Dissipation (max)12W

Screen Dissipation (max)Screen Dissipation (max)1.35W

Notes

25V heater version of the 6W6GT. Heater current is 0.3A at 25V for series-string operation.
Brans Vademecum groups 25L6GT with a large family including 6W6GT, 12W6GT, 25C5, 25CA5, 25W6GT, 35A5, 35B5, 35L6G, and many other beam power types.
Electrically identical to the 6W6GT — same section specs, same operating conditions, same output power.
Pin 8 connects cathode and suppressor grid (beam-forming plates) internally.
One of the most common output tubes in AC/DC consumer radio receivers of the 1940s and 1950s.

Pin Layout — Octal

1No Connection

2Heater

3Anode (Plate)

4

Socket-Compatible Tubes ⚠ Not electrically compatible

12AV5 12AX4 12DQ6 12E1 12J5 12J5GT 12W6GT 1H4 350B 367A 5881 6550 6A5G 6C2C 6CD6G

References

https://frank.pocnet.net/sheets/127/6/6W6GT.pdf