What is the 6FW5 vacuum tube?

The 6FW5 is a tetrode vacuum tube designed for sweep / power (se) applications. Compact sweep tube. No plate cap. 2A3-like..

What is a 6FW5 substitute or equivalent?

Direct equivalents to the 6FW5 include 6AV5GA. These share the same pinout and operating envelope, so they can usually be swapped without circuit changes — though batch-to-batch variations between manufacturers (NOS vs current production) may shift the sonic character noticeably.

What are the key specifications of the 6FW5?

Amplification factor μ ≈ 4, transconductance gm ≈ 7.3 mA/V, plate resistance rp ≈ 18.0 kΩ, max plate voltage 770 V, max plate dissipation 18 W, heater 6.3 V / 1.2 A.

Is the 6FW5 still in production?

Production status varies by year and manufacturer. The current Amperatubes catalog classifies the 6FW5 as Common availability. NOS (new-old-stock) examples from RCA, Mullard, Tung-Sol, GE, Sylvania and Telefunken trade among collectors; modern production where it exists comes mostly from JJ Electronic, Electro-Harmonix, Tung-Sol (New Sensor), Genalex, and a handful of small-batch makers.

What does the 6FW5 sound like?

Compact sweep tube. No plate cap. 2A3-like.. Sonic character also depends heavily on the circuit operating point, the surrounding tubes in the stage, and the output transformer when present — use the interactive loadline calculator on this page to explore the trade-offs.

By Jean-Michel Falligan Devergne · Reviewed May 29, 2026

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6FW5 Tetrode Vacuum Tube

Tetrode6.3V / 1.2AOctal

Sourcevinylsavor 6FW5 datasheetReviewed2026-05-29StatusDataModelCalcModelunder reviewPDF

Beam power tetrode rated at 18W for high-power output stages

Datasheet ↗

6FW5 — GE — tetrode vacuum tube — (1960)

18.0kΩ

7.3mA/V

15.0pF

0.5pF

7.00pF

GAIN4%

POWER45%

DRIVE82%

LINEARITY95%

SPECIFICATIONS

Heater6.3 V · 1.2 A

Max Plate Voltage770 V

Pa max18 W

Gain Factor4

gm7.3 mA/V

rp18.0 kΩ

Inter-electrode capacitances

Cgk15 pF

Cgp0.5 pF

Cpk7 pF

PinoutOctal

Era1960

RarityCommon

HEATER6.3V / 1.2A

MAX PLATE770V / 18W

BASEoctal

Source datasheets

3 manufacturer datasheets cross-checked for 6FW5

3 verified

EXECUTIVE SUMMARY

The 6FW5 is a indirectly-heated beam tetrode from GE, introduced around 1960. It provides a gain factor (μ) of 4 with 18.0kΩ plate resistance. Commonly used in sweep / power (se) applications. Compact sweep tube. No plate cap. 2A3-like.

APPLICATIONS

High-power output

Generic tetrode sweep / power (se) stage

HISTORY

Introduced1960ManufacturerGE

Late Production

6FW5 Datasheet

Local mirror · PDF

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METRIX TESTER

Test this tube on a Metrix

SPICE model not yet available. Loadline calculator requires calibrated Koren parameters.

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