What is a 6021 substitute or equivalent?

Direct equivalents to the 6021 include 6111, 6112 (sister submini duals). 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 6021?

Amplification factor μ ≈ 35, transconductance gm ≈ 5.4 mA/V, plate resistance rp ≈ 6.5 kΩ, max plate voltage 165 V, max plate dissipation 0.7 W, heater 6.3 V / 0.3 A.

Is the 6021 still in production?

Production status varies by year and manufacturer. The current Amperatubes catalog classifies the 6021 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 6021 sound like?

Raytheon CK6021 subminiature dual triode (cousin of 6111). Flying-lead 8-pin construction, no socket. Designed for missile / aerospace gear, popular today for ultra-compact preamp builds.. 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.

6021 Triode Vacuum Tube

Q: What is the 6021 vacuum tube?

The 6021 is a triode vacuum tube designed for preamp / driver applications. Raytheon CK6021 subminiature dual triode (cousin of 6111). Flying-lead 8-pin construction, no socket. Designed for missile / aerospace gear, popular today for ultra-compact preamp builds..

Also known as 6111 · 6112 (sister submini duals)

Medium-gain triode for driver and line stage applications

Dual triodeHeater 6.3 V · 0.3 A8-pin Submini (flying leads)2 sectionsRaytheon·CBS 1955

Plate dissipation: 0.7W
Max plate voltage: 165V
Amplification factor: 35
Transconductance: 5.4mA/V
Plate resistance: 6.5kΩ

6021

Characteristics

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

HeaterIndirectly heated

Specifications of 6021 — Heater
Heater voltageVh	6.3 V
Heater currentIh	0.3 A

Limiting valuesDatasheet maximum ratings — not to be exceeded

Specifications of 6021 — Limiting values
Plate voltageVa max	165 V
Plate dissipationPa max	0.7 W
Grid resistorRg1 max	1.1 MΩ
Peak plate voltageVao	330 V
Heater–cathode voltageVhk max	200 V

Mechanical

Specifications of 6021 — Mechanical
Base	8-pin Submini (flying leads)
Rarity	Rare
Pinout

Small signalDatasheet parameters at the reference operating point — not limits

Specifications of 6021 — Small signal
Transconductance	5.4 mA/V
Plate resistance	6.5 kΩ
Amplification factor	35

Capacitances

Specifications of 6021 — Capacitances
Grid–cathode	2.4 pF
Grid–plate	1.5 pF
Plate–cathode	0.28 pF

Charactereditorial reading, not a measurement

Specifications of 6021 — Character
Gain	35%
Power	2%
Drive	94%
Linearity	83%

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

Typical operation

Canonical operating pointModel

B+: 150 V
Load: 13 kΩ
Va: 90 V
Ia: 3.37 mA
Vg: -1.5 V
Pd: 0.30 W
Gain: 25.5 dB

At Q: Norman Koren
μ: 32.2
gm: 3.45 mA/V
rp: 9.3 kΩ

Design a stage →

Using this tube

Applications

Voltage amplifier
Phase splitter

Generic triode preamp / driver stage

Hi-Fi stereo

Replace or compare

Sources

By Jean-Michel Falligan DevergneReviewed May 29, 2026Source : Raytheon CK6021 datasheetActive model : Norman Koren

Manufacturer datasheets

9 manufacturer datasheets cross-checked for 60219 verified

6021 DatasheetLocal mirror · PDF

SPICE models

Revision and verification status

Source: Raytheon CK6021 datasheet
Reviewed: 2026-05-29
Status: DataModelCalc
Model: Norman Koren

Context

The 6021 is a dual indirectly-heated triode from Raytheon·CBS, introduced around 1955. It provides a gain factor (μ) of 35 with 6500Ω plate resistance. Commonly used in preamp / driver applications. Raytheon CK6021 subminiature dual triode (cousin of 6111). Flying-lead 8-pin construction, no socket. Designed for missile / aerospace gear, popular today for ultra-compact preamp builds.

History

Introduced: 1955
Manufacturer: Raytheon·CBS
Era: Golden Age

METRIX TESTER