What is the 7027A vacuum tube?

The 7027A is a tetrode vacuum tube designed for power (pp) applications. High-voltage 6L6. Ampeg bass tone..

What is a 7027A substitute or equivalent?

Direct equivalents to the 7027A include 6L6GC (higher voltage). 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 7027A?

Transconductance gm ≈ 6 mA/V, plate resistance rp ≈ 22.5 kΩ, max plate voltage 600 V, max plate dissipation 35 W, heater 6.3 V / 0.9 A.

Is the 7027A still in production?

Production status varies by year and manufacturer. The current Amperatubes catalog classifies the 7027A 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 7027A sound like?

High-voltage 6L6. Ampeg bass tone.. 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.

7027A Tetrode Vacuum Tube

Also known as 6L6GC (higher voltage)

Beam power tetrode rated at 35W for high-power output stages

TetrodeHeater 6.3 V · 0.9 AOctalRCA 1958

Plate dissipation: 35W
Max plate voltage: 600V
Transconductance: 6mA/V

7027A

Characteristics

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

HeaterIndirectly heated

Specifications of 7027A — Heater
Heater voltageVh	6.3 V
Heater currentIh	0.9 A

Limiting valuesDatasheet maximum ratings — not to be exceeded

Specifications of 7027A — Limiting values
Plate voltageVa max	600 V
Plate dissipationPa max	35 W

Mechanical

Specifications of 7027A — Mechanical
Base	Octal
Rarity	Sought-after
Pinout

Small signalDatasheet parameters at the reference operating point — not limits

Specifications of 7027A — Small signal
Transconductance	6 mA/V
Plate resistance	22.5 kΩ

Capacitances

Specifications of 7027A — Capacitances
Input	10 pF
Grid–plate	1.5 pF
Output	7.5 pF

Charactereditorial reading, not a measurement

Specifications of 7027A — Character
Gain	0%
Power	88%
Drive	78%
Linearity	75%

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

Typical operation

Conditions published by the manufacturers, one row per condition. Nothing is computed.

Typical operation
Setup	Va	Ia	gm	Source
Class A, single-endedpentode connection	250 V	72 mA	6 mA/V	OCR, to be checked RCA · 1959 · p. 1 · transcript

Using this tube

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

Applications

High-power output

Generic tetrode power (pp) stage

PA/public address

Replace or compare

Sources

By Jean-Michel Falligan DevergneReviewed May 29, 2026

Manufacturer datasheets

1 manufacturer datasheets cross-checked for 7027A1 verified

7027A DatasheetLocal mirror · PDF

SPICE models

Revision and verification status

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

Context

The 7027A is a indirectly-heated beam tetrode from RCA, introduced around 1958. Commonly used in power (pp) applications. High-voltage 6L6. Ampeg bass tone.

History

Introduced: 1958
Manufacturer: RCA
Era: Golden Age

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