What is a 6SN7GTB substitute or equivalent?

Direct equivalents to the 6SN7GTB include 6SN7GTA (electrically identical, GTA lacks controlled warm-up) · 6SN7GT (downrated, 300V/5W only). 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 6SN7GTB?

Amplification factor μ ≈ 20, transconductance gm ≈ 2.6 mA/V, plate resistance rp ≈ 7.7 kΩ, max plate voltage 450 V, max plate dissipation 5 W, heater 6.3 V / 0.6 A.

Is the 6SN7GTB still in production?

Production status varies by year and manufacturer. The current Amperatubes catalog classifies the 6SN7GTB 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 6SN7GTB sound like?

Late-1950s revision of the GTA adding a controlled-warm-up heater for series-string TV B+ chains. Audio behaviour identical to GTA: 450 V / 7.5 W total. The most-common production 6SN7 from the late 1950s through the 1980s.. 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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6SN7GTB Triode Vacuum Tube

Q: What is the 6SN7GTB vacuum tube?

The 6SN7GTB is a triode vacuum tube designed for preamp / driver / phase inverter applications. Late-1950s revision of the GTA adding a controlled-warm-up heater for series-string TV B+ chains. Audio behaviour identical to GTA: 450 V / 7.5 W total. The most-common production 6SN7 from the late 1950s through the 1980s..

Dual triode6.3V / 0.6AOctalSPICE

SourceRCA RC-26 (1968)Reviewed2026-05-29StatusDataModelCalcModelKoren v1PDF

Medium-gain triode for driver and line stage applications

Datasheet ↗SPICE

6SN7GTB — RCA·Sylvania·GE·Tung-Sol — triode vacuum tube — (1958)

7.7kΩ

2.6mA/V

2.2pF

4.0pF

0.70pF

GAIN20%

POWER13%

DRIVE92%

LINEARITY90%

SPECIFICATIONS

Heater6.3 V · 0.6 A

Max Plate Voltage450 V

Pa max5 W

Gain Factor20

gm2.6 mA/V

rp7.7 kΩ

Inter-electrode capacitances

Cgk2.2 pF

Cgp4 pF

Cpk0.7 pF

PinoutOctal

Era1958

RarityCommon

HEATER6.3V / 0.6A

MAX PLATE450V / 5W

BASEoctal

SECTIONS2 (dual)

Source datasheets

4 manufacturer datasheets cross-checked for 6SN7GTB

4 verified

TYPICAL OPERATING POINT

SPICE model(2 available)5 .subckt available ↓

Va325V

Ia14.53mA

Vg-9.680000000000001V

Pd4.72W

RL8kΩ

Av20.7dB

EXECUTIVE SUMMARY

The 6SN7GTB is a dual indirectly-heated triode from RCA·Sylvania·GE·Tung-Sol, introduced around 1958. It provides a gain factor (μ) of 20 with 7700Ω plate resistance. Commonly used in preamp / driver / phase inverter applications. Late-1950s revision of the GTA adding a controlled-warm-up heater for series-string TV B+ chains. Audio behaviour identical to GTA: 450 V / 7.5 W total. The most-common production 6SN7 from the late 1950s through the 1980s.

APPLICATIONS

Push-pull outputVoltage amplifierPhase splitter

Generic triode preamp / driver / phase inverter stage

• Hi-Fi stereo• Headphone amp

HISTORY

Introduced1958ManufacturerRCA·Sylvania·GE·Tung-Sol

Golden Age

6SN7GTB Datasheet

Local mirror · PDF

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METRIX TESTER

Test this tube on a Metrix

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