What is the 7AK7 vacuum tube?

The 7AK7 is a pentode vacuum tube designed for rf / preamp applications. High-Gm military pentode..

What is a 7AK7 substitute or equivalent?

Direct equivalents to the 7AK7 include None. 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 7AK7?

Transconductance gm ≈ 6 mA/V, plate resistance rp ≈ 11.5 kΩ, max plate voltage 200 V, max plate dissipation 8.5 W, heater 6.3 V / 0.8 A.

Is the 7AK7 still in production?

Production status varies by year and manufacturer. The current Amperatubes catalog classifies the 7AK7 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 7AK7 sound like?

High-Gm military pentode.. 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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7AK7 Pentode Vacuum Tube

Pentode6.3V / 0.8A7-pin MiniatureSPICE

SourceWikipedia 7AK7 (Whirlwind, B8G loctal)Reviewed2026-05-29StatusDataModelCalcModelKoren pentodePDF

Small-signal pentode for low-noise voltage amplification

Datasheet ↗SPICE

7AK7 — GE — pentode vacuum tube — (1955)

11.5kΩ

6.0mA/V

12.0pF

0.7pF

9.50pF

GAIN0%

POWER21%

DRIVE89%

LINEARITY75%

SPECIFICATIONS

Heater6.3 V · 0.8 A

Max Plate Voltage200 V

Pa max8.5 W

Gain Factor—

gm6 mA/V

rp11.5 kΩ

Inter-electrode capacitances

Cgk12 pF

Cgp0.7 pF

Cpk9.5 pF

Pinout7-pin Miniature

Era1955

RarityModerate

HEATER6.3V / 0.8A

MAX PLATE200V / 8.5W

BASEb7g

Source datasheets

2 manufacturer datasheets cross-checked for 7AK7

2 verified

EXECUTIVE SUMMARY

The 7AK7 is a indirectly-heated pentode from GE, introduced around 1955. Commonly used in rf / preamp applications. High-Gm military pentode.

HISTORY

Introduced1955ManufacturerGE

Golden Age

7AK7 Datasheet

Local mirror · PDF

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METRIX TESTER

Test this tube on a Metrix

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