What is the 250TL vacuum tube?

The 250TL (250TL / VT-130) is a triode vacuum tube designed for transmitting (set) applications. Eimac transmitting triode. Extreme power SET..

What is a 250TL substitute or equivalent?

Direct equivalents to the 250TL include VT-130. 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 250TL?

Amplification factor μ ≈ 14, transconductance gm ≈ 2.65 mA/V, plate resistance rp ≈ 5.3 kΩ, max plate voltage 4000 V, max plate dissipation 250 W, heater 5 V / 10.5 A.

Is the 250TL still in production?

Production status varies by year and manufacturer. The current Amperatubes catalog classifies the 250TL as Rare 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 250TL sound like?

Eimac transmitting triode. Extreme power SET.. 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.

250TL VT-130 Triode Vacuum Tube

Also known as VT-130

Power triode delivering 250W for push-pull and SET designs

TriodeHeater 5 V · 10.5 AUX-4Eimac 1938

Plate dissipation: 250W
Max plate voltage: 4000V
Transconductance: 2.65mA/V

250TL

Characteristics

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

HeaterDirectly heated

Specifications of 250TL — Heater
Heater voltageVh	5 V
Heater currentIh	10.5 A

Limiting valuesDatasheet maximum ratings — not to be exceeded

Specifications of 250TL — Limiting values
Plate voltageVa max	4000 V
Plate dissipationPa max	250 W

Mechanical

Specifications of 250TL — Mechanical
Base	UX-4
Rarity	Rare
Pinout

Small signalDatasheet parameters at the reference operating point — not limits

Specifications of 250TL — Small signal
Transconductance	2.65 mA/V
Plate resistance	5.3 kΩ
Amplification factor	14

Capacitances

Specifications of 250TL — Capacitances
Grid–cathode	3.7 pF
Grid–plate	3 pF
Plate–cathode	0.7 pF

Charactereditorial reading, not a measurement

Specifications of 250TL — Character
Gain	14%
Power	100%
Drive	95%
Linearity	93%

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

Using this tube

Interactive loadline calculator not available for this tube yet — it needs calibrated Koren or Ayumi parameters.

Applications

SET output
Push-pull output

Generic triode transmitting (set) stage

PA/public address

Replace or compare

Sources

By Jean-Michel Falligan DevergneReviewed May 29, 2026

Manufacturer datasheets

3 manufacturer datasheets cross-checked for 250TL / VT-1303 verified

250TL DatasheetLocal mirror · PDF

SPICE models

Revision and verification status

Source: Eimac
Reviewed: 2026-05-29
Status: DataModelCalc
Model: under review

Context

The 250TL is a directly-heated triode from Eimac, introduced around 1938. It provides a gain factor (μ) of 14 with 5283Ω plate resistance. Commonly used in transmitting (set) applications. Eimac transmitting triode. Extreme power SET.

History

Introduced: 1938
Manufacturer: Eimac
Era: Pre-War

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