What is the E180F vacuum tube?

The E180F is a pentode vacuum tube designed for preamp applications. Frame-grid. Very high Gm..

What is a E180F substitute or equivalent?

Direct equivalents to the E180F include 6688 class. 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 E180F?

Amplification factor μ ≈ 50, transconductance gm ≈ 16.5 mA/V, plate resistance rp ≈ 90.0 kΩ, max plate voltage 210 V, max plate dissipation 3 W, heater 6.3 V / 0.3 A.

Is the E180F still in production?

Production status varies by year and manufacturer. The current Amperatubes catalog classifies the E180F as Sought-after 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 E180F sound like?

Frame-grid. Very high Gm.. 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.

E180F Pentode Vacuum Tube

Also known as 6688 class

Small-signal pentode for low-noise voltage amplification

PentodeHeater 6.3 V · 0.3 A9-pin NovalPhilips 1958

Plate dissipation: 3W
Max plate voltage: 210V
Amplification factor: 50
Transconductance: 16.5mA/V
Plate resistance: 90kΩ

E180F

Characteristics

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

HeaterIndirectly heated

Specifications of E180F — Heater
Heater voltageVh	6.3 V
Heater currentIh	0.3 A

Limiting valuesDatasheet maximum ratings — not to be exceeded

Specifications of E180F — Limiting values
Plate voltageVa max	210 V
Screen voltageVg2 max	175 V
Plate dissipationPa max	3 W
Screen dissipationPg2 max	0.9 W
Cathode currentIk max	25 mA
Grid resistorRg1 max	250 kΩ
Peak plate voltageVao	400 V

Mechanical

Specifications of E180F — Mechanical
Base	9-pin Noval
Rarity	Sought-after
Pinout

Small signalDatasheet parameters at the reference operating point — not limits

Specifications of E180F — Small signal
Transconductance	16.5 mA/V
Plate resistance	90 kΩ
Amplification factor	50

Capacitances

Specifications of E180F — Capacitances
Input	7.5 pF
Grid–plate	0.03 pF
Output	3 pF

Charactereditorial reading, not a measurement

Specifications of E180F — Character
Gain	50%
Power	8%
Drive	10%
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 : Philips E180F/6688 datasheetActive model : Koren pentode

Manufacturer datasheets

5 manufacturer datasheets cross-checked for E180F5 verified

Triode-connectedAEGMärz 1960 (Z 40 / Sf-Sick 57162) — 7 pages

gm: 18.5 mA/V
µ: 225
Ra: 2.7 Ω

E180F DatasheetLocal mirror · PDF

SPICE models

Revision and verification status

Source: Philips E180F/6688 datasheet
Reviewed: 2026-05-29
Status: DataModelCalc
Model: Koren pentode

Context

The E180F is a indirectly-heated pentode from Philips, introduced around 1958. It provides a gain factor (μ) of 50 with 90.0kΩ plate resistance. Commonly used in preamp applications. Frame-grid. Very high Gm.

History

Introduced: 1958
Manufacturer: Philips
Era: Golden Age

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