350B

Name: 350B
Brand: Western Electric

Beam Tetrode — Octal — Western Electric

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

CV1799350A

Similar Tubes (Not Drop-In Compatible)

25BK5

Similar beam tetrode but Noval base with 25V heater vs Octal/6.3V for 350B

367A

Same internal structure and electricals as 350B but different base configuration and shorter/rounder glass envelope

6L6

Same octal pinout and similar beam tetrode characteristics, but 350B draws 1.6A heater current vs 0.9A for 6L6 — heater transformer must be rated accordingly

Electrical Specifications

Section 1 — Beam Tetrode

Absolute Maximum

Anode Voltage (max)Anode Voltage (max)360V

Screen Voltage (max)Screen Voltage (max)270V

Anode Dissipation (max)Anode Dissipation (max)27W

Screen Dissipation (max)Screen Dissipation (max)4W

Notes

The 350A, 350B, and 367A have essentially identical static characteristics but differ in lead-out arrangement and basing.
Heater current is 1.6A — nearly double that of the 6L6 (0.9A). While the pinout is identical to the 6L6 family, the 350B is not a drop-in replacement in circuits designed for 6L6 heater current without verifying the heater supply can handle the additional load.
Maximum grid circuit resistance differs by bias type: 0.1 MΩ for fixed bias, 0.5 MΩ for cathode bias.
Developed by Bell Telephone Laboratories and manufactured by Western Electric for AT&T telephone system applications. The USN-CW-350B is the US Navy designation for this tube.

Pin Layout — Octal

1No Connection

2Heater

3Anode (Plate)

4

Socket-Compatible Tubes ⚠ Not electrically compatible

12AV5 12AX4 12DQ6 12E1 12J5 12J5GT 12W6GT 1H4 25L6GT 367A 5881 6550 6A5G 6C2C 6CD6G

References