What is the E55L vacuum tube?

The E55L is a pentode vacuum tube designed for power / driver applications. Extreme Gm pentode. Legendary..

What is a E55L substitute or equivalent?

Direct equivalents to the E55L include 8233, CV5808. 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 E55L?

Amplification factor μ ≈ 30, transconductance gm ≈ 45 mA/V, plate resistance rp ≈ 20.0 kΩ, max plate voltage 200 V, max plate dissipation 10 W, heater 6.3 V / 0.6 A.

Is the E55L still in production?

Production status varies by year and manufacturer. The current Amperatubes catalog classifies the E55L 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 E55L sound like?

Extreme Gm pentode. Legendary.. 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

←E55L

← E280F E80L →Compare → 8233

E55L Pentode Vacuum Tube

Pentode6.3V / 0.6A9-pin NovalSPICE

SourcePhilips E55L/8233 datasheetReviewed2026-05-29StatusDataModelCalcModelKoren pentodePDF

Power pentode delivering up to 10W in pentode, UL, or triode mode

Datasheet ↗SPICE

E55L — Philips — pentode vacuum tube — (1958)

20.0kΩ

45.0mA/V

18.0pF

0.1pF

4.00pF

GAIN30%

POWER25%

DRIVE80%

LINEARITY85%

SPECIFICATIONS

Heater6.3 V · 0.6 A

Max Plate Voltage200 V

Pa max10 W

Gain Factor30

gm45 mA/V

rp20.0 kΩ

Inter-electrode capacitances

Cgk18 pF

Cgp0.11 pF

Cpk4 pF

Pinout9-pin Noval

Era1958

RaritySought-after

HEATER6.3V / 0.6A

MAX PLATE200V / 10W

BASEmagnoval

Source datasheets

3 manufacturer datasheets cross-checked for E55L

3 verified

Triode-connectedPhilips10.10.1961 (7Z2 series; Tentative data)

Specs when the screen grid (g2) is tied to the anode — the tube acts as a triode.

125 V

Vg1

-3 V

55.5 mA

50 mA/V

According to Philips (SQ series; trilingual EN/FR/DE) (10.10.1961 (7Z2 series; Tentative data)): « triode connection »

EXECUTIVE SUMMARY

The E55L is a indirectly-heated pentode from Philips, introduced around 1958. It provides a gain factor (μ) of 30 with 20.0kΩ plate resistance. Commonly used in power / driver applications. Extreme Gm pentode. Legendary.

APPLICATIONS

Power output

Generic pentode power / driver stage

VS 8233

Pd 0%Full comparison →

HISTORY

Introduced1958ManufacturerPhilips

Golden Age

E55L Datasheet

Local mirror · PDF

↗

METRIX TESTER

Test this tube on a Metrix

SIMILAR PENTODES

View all →

12SJ7Preamp 307APower/Output 310APreamp 35LR6Sweep / Power 47Power/Output 4P1LPower (SET output) — DHT pentode 5639Video / wideband (power)5654RF / Preamp