What is the 816 vacuum tube?

The 816 is a rectifier vacuum tube designed for rectifier applications. Mercury vapor half-wave. Blue glow magic..

What is a 816 substitute or equivalent?

Direct equivalents to the 816 include VT-216. 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.

Is the 816 still in production?

Production status varies by year and manufacturer. The current Amperatubes catalog classifies the 816 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 816 sound like?

Mercury vapor half-wave. Blue glow 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.

816 Rectifier Vacuum Tube

Also known as VT-216

Full-wave rectifier for vacuum tube power supply designs

RectifierHeater 2.5 V · 2 AUX-4RCA·Sylvania 1936

Max DC output current: 125mA
Peak inverse voltage: 7500V
Peak anode current: 500mA
Max plate voltage: 1500V

816

Characteristics

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

HeaterDirectly heated

Specifications of 816 — Heater
Heater voltageVh	2.5 V
Heater currentIh	2 A

Rectifier limitsDatasheet maximum ratings — not to be exceeded

Specifications of 816 — Rectifier limits
Io max (DC output current)	125 mA
Peak inverse voltage (PIV)	7500 V
Peak anode current	500 mA
Tube voltage drop at Io	15 V
Max Plate V	1500 V

Mechanical

Specifications of 816 — Mechanical
Base	UX-4
Rarity	Sought-after
Pinout

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

Power supply rectification

Generic rectifier rectifier stage

Replace or compare

Sources

By Jean-Michel Falligan DevergneReviewed May 29, 2026Source : cap audit 2026-05-09

Manufacturer datasheets

1 manufacturer datasheets cross-checked for 8161 verified

816 DatasheetLocal mirror · PDF

SPICE models

Revision and verification status

Source: cap audit 2026-05-09
Reviewed: 2026-05-29
Status: DataModelCalc
Model: under review

Context

The 816 is a directly-heated rectifier from RCA·Sylvania, introduced around 1936. Commonly used in rectifier applications. Mercury vapor half-wave. Blue glow magic.

History

Introduced: 1936
Manufacturer: RCA·Sylvania
Era: Pre-War

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