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.

6FW5 Tetrode Vacuum Tube

Also known as 6AV5GA

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

TetrodeHeater 6.3 V · 1.2 AOctalGE 1960

Plate dissipation: 18W
Max plate voltage: 770V
Transconductance: 7.3mA/V

6FW5

Characteristics

Datasheet values, once each. Every value cites its sheet.

HeaterIndirectly heated

Specifications of 6FW5 — Heater
Heater voltageVh	6.3 V
Heater currentIh	1.2 A

Limiting valuesDatasheet maximum ratings — not to be exceeded

Specifications of 6FW5 — Limiting values
Plate voltageVa max	770 V
Plate dissipationPa max	18 W

Mechanical

Specifications of 6FW5 — Mechanical
Base	Octal
Rarity	Common
Pinout

Small signalDatasheet parameters at the reference operating point — not limits

Specifications of 6FW5 — Small signal
Transconductance	7.3 mA/V
Plate resistance	18 kΩ
Amplification factor	4

Capacitances

Specifications of 6FW5 — Capacitances
Input	15 pF
Grid–plate	0.5 pF
Output	7 pF

Charactereditorial reading, not a measurement

Specifications of 6FW5 — Character
Gain	4%
Power	45%
Drive	82%
Linearity	95%

datasheet cited · model or editorial reading · catalogue value, no citation attached yet · nothing invented

Typical operation

Conditions published by the manufacturers, one row per condition. Nothing is computed.

Typical operation
Setup	Va	Vg2	Vg1 / Rk	Ia	Ig2	gm	rp	Source
pentode connection, single-endedclass not stated · fixed bias	250 V	150 V	-22.5 V	65 mA	1.8 mA	7.3 mA/V	18 kΩ	OCR, to be checked Tung-Sol · 1961 · p. 2 · transcript

Using this tube

Interactive loadline calculator not available for this tube yet — it needs calibrated Koren or Ayumi parameters.

Applications

High-power output

Generic tetrode sweep / power (se) stage

Replace or compare

Sources

By Jean-Michel Falligan DevergneReviewed May 29, 2026Source : vinylsavor 6FW5 datasheet

Manufacturer datasheets

3 manufacturer datasheets cross-checked for 6FW53 verified

6FW5 DatasheetLocal mirror · PDF

SPICE models

Revision and verification status

Source: vinylsavor 6FW5 datasheet
Reviewed: 2026-05-29
Status: DataModelCalc
Model: under review

Context

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.

History

Introduced: 1960
Manufacturer: GE
Era: Late Production

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