What is the 6888 vacuum tube?

The 6888 is a pentode vacuum tube designed for preamp applications. Enhanced pentode..

What are the key specifications of the 6888?

Amplification factor μ ≈ 10, transconductance gm ≈ 5 mA/V, max plate voltage 250 V, max plate dissipation 8 W, heater 6.3 V / 0.8 A.

Is the 6888 still in production?

Production status varies by year and manufacturer. The current Amperatubes catalog classifies the 6888 as Moderate 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 6888 sound like?

Enhanced pentode.. 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.

6888 Pentode Vacuum Tube

Small-signal pentode for low-noise voltage amplification

PentodeHeater 6.3 V · 0.8 A7-pin MiniatureRCA 1960

Plate dissipation: 8W
Max plate voltage: 250V
Transconductance: 5mA/V

6888

Characteristics

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

HeaterIndirectly heated

Specifications of 6888 — Heater
Heater voltageVh	6.3 V
Heater currentIh	0.8 A

Limiting valuesDatasheet maximum ratings — not to be exceeded

Specifications of 6888 — Limiting values
Plate voltageVa max	250 V
Plate dissipationPa max	8 W

Mechanical

Specifications of 6888 — Mechanical
Base	7-pin Miniature
Rarity	Moderate
Pinout

Small signalDatasheet parameters at the reference operating point — not limits

Specifications of 6888 — Small signal
Transconductance	5 mA/V
Amplification factor	10

Capacitances

Specifications of 6888 — Capacitances
Input	12 pF
Grid–plate	0.7 pF
Output	6.5 pF

Charactereditorial reading, not a measurement

Specifications of 6888 — Character
Gain	10%
Power	20%
Drive	50%
Linearity	95%

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

Using this tube

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Sources

By Jean-Michel Falligan DevergneReviewed May 29, 2026Source : Surplus Sales / Radiomuseum 6888 (octal Sylvania)Active model : Koren pentode

Manufacturer datasheets

1 manufacturer datasheets cross-checked for 68881 verified

6888 DatasheetLocal mirror · PDF

SPICE models

Revision and verification status

Source: Surplus Sales / Radiomuseum 6888 (octal Sylvania)
Reviewed: 2026-05-29
Status: DataModelCalc
Model: Koren pentode

Context

The 6888 is a indirectly-heated pentode from RCA, introduced around 1960. Commonly used in preamp applications. Enhanced pentode.

History

Introduced: 1960
Manufacturer: RCA
Era: Late Production

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