What is the GI-7B vacuum tube?

The GI-7B (GI-7B / ГИ-7Б) is a triode vacuum tube designed for transmitting / hf-vhf applications. Coaxial microwave triode. Ham radio favorite..

What is a GI-7B substitute or equivalent?

Direct equivalents to the GI-7B include GI-70B. 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 GI-7B?

Amplification factor μ ≈ 30, transconductance gm ≈ 23 mA/V, plate resistance rp ≈ 1.3 kΩ, max plate voltage 2500 V, max plate dissipation 350 W, heater 12.6 V / 2.05 A.

Is the GI-7B still in production?

Production status varies by year and manufacturer. The current Amperatubes catalog classifies the GI-7B 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 GI-7B sound like?

Coaxial microwave triode. Ham radio favorite.. 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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GI-7B GI-7B / ГИ-7Б Triode Vacuum Tube

Triode12.6V / 2.05ACoaxial ring

SourceG8WRB GI-7B datasheetReviewed2026-05-29StatusDataModelCalcModelunder reviewPDF

Power triode delivering 350W for push-pull and SET designs

Datasheet ↗

GI-7B / ГИ-7Б — Svetlana — triode vacuum tube — (1960)

1.3kΩ

23.0mA/V

11.0pF

4.5pF

0.07pF

GAIN30%

POWER100%

DRIVE99%

LINEARITY85%

SPECIFICATIONS

Heater12.6 V · 2.05 A

Max Plate Voltage2500 V

Pa max350 W

Gain Factor30

gm23 mA/V

rp1.3 kΩ

Inter-electrode capacitances

Cgk11 pF

Cgp4.5 pF

Cpk0.075 pF

PinoutCoaxial ring

Era1960

RarityModerate

HEATER12.6V / 2.05A

MAX PLATE2500V / 350W

BASEcoaxial

Source datasheets

1 manufacturer datasheets cross-checked for GI-7B / ГИ-7Б

1 verified

EXECUTIVE SUMMARY

The GI-7B is a indirectly-heated triode from Svetlana, introduced around 1960. It provides a gain factor (μ) of 30 with 1300Ω plate resistance. Commonly used in transmitting / hf-vhf applications. Coaxial microwave triode. Ham radio favorite.

APPLICATIONS

SET outputPush-pull outputHeadphone output

Generic triode transmitting / hf-vhf stage

• Headphone amp• PA/public address

HISTORY

Introduced1960ManufacturerSvetlana

Late Production

GI-7B 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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