What is the CV3998 vacuum tube?

The CV3998 is a pentode vacuum tube designed for preamp applications. Military E180F..

What is a CV3998 substitute or equivalent?

Direct equivalents to the CV3998 include E180F mil. 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 CV3998?

Transconductance gm ≈ 16.5 mA/V, max plate voltage 400 V, max plate dissipation 3 W, heater 6.3 V / 0.3 A.

Is the CV3998 still in production?

Production status varies by year and manufacturer. The current Amperatubes catalog classifies the CV3998 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 CV3998 sound like?

Military E180F.. 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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CV3998 Pentode Vacuum Tube

Pentode6.3V / 0.3A7-pin MiniatureSPICE

Sourcemullard.org CV3998/E180F gold-pinReviewed2026-05-29StatusDataModelCalcModelKoren pentodePDF

Small-signal pentode for low-noise voltage amplification

Datasheet ↗SPICE

CV3998 — Mullard — pentode vacuum tube — (1958)

16.5mA/V

7.9pF

0.0pF

2.90pF

GAIN0%

POWER8%

DRIVE50%

LINEARITY75%

SPECIFICATIONS

Heater6.3 V · 0.3 A

Max Plate Voltage400 V

Pa max3 W

Gain Factor—

gm16.5 mA/V

rp—

Inter-electrode capacitances

Cgk7.9 pF

Cgp0.03 pF

Cpk2.9 pF

Pinout7-pin Miniature

Era1958

RarityModerate

HEATER6.3V / 0.3A

MAX PLATE400V / 3W

BASEminiature-7

Source datasheets

1 manufacturer datasheets cross-checked for CV3998

1 verified

EXECUTIVE SUMMARY

The CV3998 is a indirectly-heated pentode from Mullard, introduced around 1958. Commonly used in preamp applications. Military E180F.

APPLICATIONS

Voltage amplifier

Generic pentode preamp stage

HISTORY

Introduced1958ManufacturerMullard

Golden Age

CV3998 Datasheet

Local mirror · PDF

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METRIX TESTER

Test this tube on a Metrix

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