What is the 26 vacuum tube?

The 26 (26 / UX-226) is a triode vacuum tube designed for preamp applications. Creamy tone. Early DHT magic..

What is a 26 substitute or equivalent?

Direct equivalents to the 26 include UX-226, CX-326. 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 26?

Amplification factor μ ≈ 8, transconductance gm ≈ 1.1 mA/V, plate resistance rp ≈ 7.6 kΩ, max plate voltage 180 V, max plate dissipation 1.5 W, heater 1.5 V / 1.05 A.

Is the 26 still in production?

Production status varies by year and manufacturer. The current Amperatubes catalog classifies the 26 as Collector 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 26 sound like?

Creamy tone. Early DHT magic.. 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

←26

← 250TL 27 →Compare…

26 26 / UX-226 Triode Vacuum Tube

Triode1.5V / 1.05AUX-4

SourceRCA·GEReviewed2026-05-29StatusDataModelCalcModelunder reviewPDF

Low-mu triode with excellent linearity for driver and line stages

Datasheet ↗

26 / UX-226 — RCA·GE — triode vacuum tube — (1926)

7.6kΩ

1.1mA/V

2.8pF

8.1pF

2.50pF

GAIN8%

POWER4%

DRIVE92%

LINEARITY95%

SPECIFICATIONS

Heater1.5 V · 1.05 A

Max Plate Voltage180 V

Pa max1.5 W

Gain Factor8

gm1.1 mA/V

rp7.6 kΩ

Inter-electrode capacitances

Cgk2.8 pF

Cgp8.1 pF

Cpk2.5 pF

PinoutUX-4

Era1926

RarityCollector

HEATER1.5V / 1.05A

MAX PLATE180V / 1.5W

BASEux4

Source datasheets

5 manufacturer datasheets cross-checked for 26 / UX-226

5 verified

EXECUTIVE SUMMARY

The 26 is a directly-heated triode from RCA·GE, introduced around 1926. It provides a gain factor (μ) of 8 with 7600Ω plate resistance. Commonly used in preamp applications. Creamy tone. Early DHT magic.

APPLICATIONS

Voltage amplifierLine stage

Generic triode preamp stage

• Hi-Fi stereo• Headphone amp

HISTORY

Introduced1926ManufacturerRCA·GE

Pre-War

26 Datasheet

Local mirror · 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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