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.

CV3998 Pentode Vacuum Tube

Also known as E180F mil

Small-signal pentode for low-noise voltage amplification

PentodeHeater 6.3 V · 0.3 A7-pin MiniatureMullard 1958

Plate dissipation: 3W
Max plate voltage: 400V
Transconductance: 16.5mA/V

CV3998

Characteristics

Datasheet values, once each. Every value cites its sheet.

HeaterIndirectly heated

Specifications of CV3998 — Heater
Heater voltageVh	6.3 V
Heater currentIh	0.3 A

Limiting valuesDatasheet maximum ratings — not to be exceeded

Specifications of CV3998 — Limiting values
Plate voltageVa max	400 V
Screen voltageVg2 max	150 V
Plate dissipationPa max	3 W

Mechanical

Specifications of CV3998 — Mechanical
Base	7-pin Miniature
Rarity	Moderate
Pinout

Small signalDatasheet parameters at the reference operating point — not limits

Specifications of CV3998 — Small signal
Transconductance	16.5 mA/V

Capacitances

Specifications of CV3998 — Capacitances
Input	7.9 pF
Grid–plate	0.03 pF
Output	2.9 pF

Charactereditorial reading, not a measurement

Specifications of CV3998 — Character
Gain	0%
Power	8%
Drive	50%
Linearity	75%

datasheet cited · model or editorial reading · catalogue value, no citation attached yet · nothing invented

Using this tube

Applications

Voltage amplifier

Generic pentode preamp stage

Replace or compare

Sources

By Jean-Michel Falligan DevergneReviewed May 29, 2026Source : mullard.org CV3998/E180F gold-pinActive model : Koren pentode

Manufacturer datasheets

1 manufacturer datasheets cross-checked for CV39981 verified

CV3998 DatasheetLocal mirror · PDF

SPICE models

Revision and verification status

Source: mullard.org CV3998/E180F gold-pin
Reviewed: 2026-05-29
Status: DataModelCalc
Model: Koren pentode

Context

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

History

Introduced: 1958
Manufacturer: Mullard
Era: Golden Age

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