What is the 6888 vacuum tube?

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

What is a 6888 substitute or equivalent?

Direct equivalents to the 6888 include None. 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 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.

By Jean-Michel Falligan Devergne · Reviewed May 29, 2026

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6888 Pentode Vacuum Tube

Pentode6.3V / 0.8A7-pin MiniatureSPICE

SourceSurplus Sales / Radiomuseum 6888 (octal Sylvania)Reviewed2026-05-29StatusDataModelCalcModelKoren pentodePDF

Small-signal pentode for low-noise voltage amplification

Datasheet ↗SPICE

6888 — RCA — pentode vacuum tube — (1960)

5.0mA/V

12.0pF

0.7pF

6.50pF

GAIN10%

POWER20%

DRIVE50%

LINEARITY95%

SPECIFICATIONS

Heater6.3 V · 0.8 A

Max Plate Voltage250 V

Pa max8 W

Gain Factor10

gm5 mA/V

rp—

Inter-electrode capacitances

Cgk12 pF

Cgp0.7 pF

Cpk6.5 pF

Pinout7-pin Miniature

Era1960

RarityModerate

HEATER6.3V / 0.8A

MAX PLATE250V / 8W

BASEb7g

Source datasheets

1 manufacturer datasheets cross-checked for 6888

1 verified

EXECUTIVE SUMMARY

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

HISTORY

Introduced1960ManufacturerRCA

Late Production

6888 Datasheet

Local mirror · PDF

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METRIX TESTER

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