What is the 6350 vacuum tube?

The 6350 is a triode vacuum tube designed for preamp applications. IBM computer tube. 12AU7 cousin, tighter spec..

What is a 6350 substitute or equivalent?

Direct equivalents to the 6350 include None standard. 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 6350?

Amplification factor μ ≈ 18, transconductance gm ≈ 4.6 mA/V, plate resistance rp ≈ 3.9 kΩ, max plate voltage 330 V, max plate dissipation 4 W, heater 6.3 V / 0.6 A.

Is the 6350 still in production?

Production status varies by year and manufacturer. The current Amperatubes catalog classifies the 6350 as Moderate 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 6350 sound like?

IBM computer tube. 12AU7 cousin, tighter spec.. 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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6350 Triode Vacuum Tube

Dual triode6.3V / 0.6A9-pin NovalSPICE

SourceGE·RCAReviewed2026-05-29StatusDataModelCalcModelAyumi NakabayashiPDF

Medium-gain triode for driver and line stage applications

Datasheet ↗SPICE

6350 — GE·RCA — triode vacuum tube — (1957)

3.9kΩ

4.6mA/V

3.6pF

3.2pF

0.60pF

GAIN18%

POWER10%

DRIVE96%

LINEARITY91%

SPECIFICATIONS

Heater6.3 V · 0.6 A

Max Plate Voltage330 V

Pa max4 W

Gain Factor18

gm4.6 mA/V

rp3.9 kΩ

Inter-electrode capacitances

Cgk3.6 pF

Cgp3.2 pF

Cpk0.6 pF

Pinout9-pin Noval

Era1957

RarityModerate

HEATER6.3V / 0.6A

MAX PLATE330V / 4W

BASEnoval

SECTIONS2 (dual)

Source datasheets

4 manufacturer datasheets cross-checked for 6350

4 verified

TYPICAL OPERATING POINT

Va165V

Ia9.87mA

Vg-6V

Pd1.63W

RL8kΩ

Av21.2dB

EXECUTIVE SUMMARY

The 6350 is a dual indirectly-heated triode from GE·RCA, introduced around 1957. It provides a gain factor (μ) of 18 with 3900Ω plate resistance. Commonly used in preamp applications. IBM computer tube. 12AU7 cousin, tighter spec.

APPLICATIONS

Voltage amplifierLine stagePhase splitter

Generic triode preamp stage

• Hi-Fi stereo• Headphone amp

HISTORY

Introduced1957ManufacturerGE·RCA

Golden Age

6350 Datasheet

Local mirror · PDF

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METRIX TESTER

Test this tube on a Metrix

SIMILAR TRIODES

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