What is the 8233 vacuum tube?

The 8233 (8233 / E55L) is a pentode vacuum tube designed for power / driver applications. E55L by another name. Frame-grid legend..

What is a 8233 substitute or equivalent?

Direct equivalents to the 8233 include E55L, 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 8233?

Transconductance gm ≈ 45 mA/V, max plate voltage 300 V, max plate dissipation 10 W, heater 6.3 V / 0.6 A.

Is the 8233 still in production?

Production status varies by year and manufacturer. The current Amperatubes catalog classifies the 8233 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 8233 sound like?

E55L by another name. Frame-grid legend.. 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 9, 2026

←8233

← 816 8298A →Compare → E55L

8233 8233 / E55L Pentode Vacuum Tube

Pentode6.3V / 0.6A9-pin Magnoval

Sourceaudit-eu_a (CLEAN — matches canonical datasheet)Reviewed2026-05-09StatusDataModelCalcModelunder reviewPDF

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

Datasheet ↗

8233 / E55L — Philips·Mullard — pentode vacuum tube — (1958)

45.0mA/V

14.0pF

0.7pF

10.00pF

GAIN0%

POWER25%

DRIVE50%

LINEARITY75%

SPECIFICATIONS

Heater6.3 V · 0.6 A

Max Plate Voltage300 V

Pa max10 W

Gain Factor—

gm45 mA/V

rp—

Inter-electrode capacitances

Cgk14 pF

Cgp0.7 pF

Cpk10 pF

Pinout9-pin Magnoval

Era1958

RaritySought-after

HEATER6.3V / 0.6A

MAX PLATE300V / 10W

BASEmagnoval

EXECUTIVE SUMMARY

The 8233 is a indirectly-heated pentode from Philips·Mullard, introduced around 1958. Commonly used in power / driver applications. E55L by another name. Frame-grid legend.

APPLICATIONS

Power output

Generic pentode power / driver stage

VS E55L

Pd 0%Full comparison →

HISTORY

Introduced1958ManufacturerPhilips·Mullard

Golden Age

8233 Datasheet

Frank's Electron Tube Pages · PDF

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METRIX TESTER

Test this tube on a Metrix

SPICE model not yet available. Loadline calculator requires calibrated Koren parameters.

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