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Tube Tinker — Electron Tube Database

Tube cross-reference

6U8 alternatives, equivalents, and replacements

Review exact electrical variations and directional substitutions recorded for the 6U8 voltage radio detector converter. Compare core specifications and verify every restriction before using a replacement.

Exact variations of 6U8

These designations belong to the same electrical variation group. Their names may differ because of international standards, manufacturing tolerances, or materials, but they are recorded as electrically equivalent—not merely substitutes.

  • ECF82

    Voltage Radio Detector Converter

    Base
    B9A
    Socket
    B9A
    Base pins
    9
    Sections
    2
    Heater voltage
    6.3 V
    Heater current
    0.45 A

Replacement tubes for 6U8

The following tubes are recorded as possible replacements for 6U8. This direction does not establish that 6U8 can replace them.

ECF80

Voltage Triode Pentode

Foreign To American

The database records ECF80 as a possible replacement for6U8.

No special restrictions are recorded for this substitution.

SpecificationOriginal tubeReplacement
Tube typeVoltage Radio Detector ConverterVoltage Triode Pentode
ConstructionPentode-TriodePentode-Triode
Base9AE9C12
SocketB9AB9A
Base pins99
Sections22
Heater voltage6.3 V6.3 V
Heater current0.45 A0.43 A
ECF82

Voltage Radio Detector Converter

Foreign To American

The database records ECF82 as a possible replacement for6U8.

No special restrictions are recorded for this substitution.

SpecificationOriginal tubeReplacement
Tube typeVoltage Radio Detector ConverterVoltage Radio Detector Converter
ConstructionPentode-TriodePentode-Triode
Base9AEB9A
SocketB9AB9A
Base pins99
Sections22
Heater voltage6.3 V6.3 V
Heater current0.45 A0.45 A
6678

Voltage Radio Detector Converter

Receiving To Industrial Tubes

The database records 6678 as a possible replacement for6U8.

No special restrictions are recorded for this substitution.

SpecificationOriginal tubeReplacement
Tube typeVoltage Radio Detector ConverterVoltage Radio Detector Converter
ConstructionPentode-TriodePentode-Triode
Base9AENot recorded
SocketB9AIO
Base pins98
Sections22
Heater voltage6.3 V6.3 V
Heater current0.45 A0.45 A
7731

Voltage Triode Pentode

Receiving To Industrial Tubes

The database records 7731 as a possible replacement for6U8.

No special restrictions are recorded for this substitution.

SpecificationOriginal tubeReplacement
Tube typeVoltage Radio Detector ConverterVoltage Triode Pentode
ConstructionPentode-TriodePentode-Triode
Base9AEE9-1 / 9AE
SocketB9AB9A
Base pins99
Sections22
Heater voltage6.3 V6.3 V
Heater current0.45 A0.45 A
6CQ8

Voltage Radio Detector Converter

Receiving Tubes

The database records 6CQ8 as a possible replacement for6U8.

  • Not suitable for all circuits
SpecificationOriginal tubeReplacement
Tube typeVoltage Radio Detector ConverterVoltage Radio Detector Converter
ConstructionPentode-TriodeTetrode-Triode
Base9AE9GE
SocketB9AB9A
Base pins99
Sections22
Heater voltage6.3 V6.3 V
Heater current0.45 A0.45 A
6EA8

Voltage Radio Detector Converter

Receiving Tubes

The database records 6EA8 as a possible replacement for6U8.

No special restrictions are recorded for this substitution.

SpecificationOriginal tubeReplacement
Tube typeVoltage Radio Detector ConverterVoltage Radio Detector Converter
ConstructionPentode-TriodePentode-Triode
Base9AENot recorded
SocketB9AB9A
Base pins99
Sections22
Heater voltage6.3 V6.3 V
Heater current0.45 A0.45 A
6KD8

Voltage Radio Detector Converter

Receiving Tubes

The database records 6KD8 as a possible replacement for6U8.

  • Parallel heater circuits only
SpecificationOriginal tubeReplacement
Tube typeVoltage Radio Detector ConverterVoltage Radio Detector Converter
ConstructionPentode-TriodePentode-Triode
Base9AE9AE
SocketB9AB9A
Base pins99
Sections22
Heater voltage6.3 V6.3 V
Heater current0.45 A0.4 A
6LN8

Voltage Radio Detector Converter

Receiving Tubes

The database records 6LN8 as a possible replacement for6U8.

No special restrictions are recorded for this substitution.

SpecificationOriginal tubeReplacement
Tube typeVoltage Radio Detector ConverterVoltage Radio Detector Converter
ConstructionPentode-TriodePentode-Triode
Base9AE9DC
SocketB9AB9A
Base pins99
Sections22
Heater voltage6.3 V6 V
Heater current0.45 A0.45 A
6MQ8

Voltage Triode Pentode

Receiving Tubes

The database records 6MQ8 as a possible replacement for6U8.

  • Parallel heater circuits only
SpecificationOriginal tubeReplacement
Tube typeVoltage Radio Detector ConverterVoltage Triode Pentode
ConstructionPentode-TriodePentode-Triode
Base9AENot recorded
SocketB9AB9A
Base pins99
Sections22
Heater voltage6.3 V6.3 V
Heater current0.45 A0.535 A
6U8A

Voltage Radio Detector Converter

Receiving Tubes

The database records 6U8A as a possible replacement for6U8.

No special restrictions are recorded for this substitution.

SpecificationOriginal tubeReplacement
Tube typeVoltage Radio Detector ConverterVoltage Radio Detector Converter
ConstructionPentode-TriodePentode-Triode
Base9AEEIA 9AE
SocketB9AB9A
Base pins99
Sections22
Heater voltage6.3 V6.3 V
Heater current0.45 A0.45 A

Where 6U8 can be used as the replacement

In these recorded relationships, 6U8 is the replacement tube. The listed original tubes are not automatically suitable as replacements for 6U8.

ECF82

Voltage Radio Detector Converter

American To Foreign

The database records 6U8 as a possible replacement forECF82.

No special restrictions are recorded for this substitution.

Specification6U8 replacementOriginal tube
Tube typeVoltage Radio Detector ConverterVoltage Radio Detector Converter
ConstructionPentode-TriodePentode-Triode
Base9AEB9A
SocketB9AB9A
Base pins99
Sections22
Heater voltage6.3 V6.3 V
Heater current0.45 A0.45 A
6AX8

Voltage Pentode - Sharp Cutoff (single)

Receiving Tubes

The database records 6U8 as a possible replacement for6AX8.

No special restrictions are recorded for this substitution.

Specification6U8 replacementOriginal tube
Tube typeVoltage Radio Detector ConverterVoltage Pentode - Sharp Cutoff (single)
ConstructionPentode-TriodePentode-Triode
Base9AE9AE
SocketB9AB9A
Base pins99
Sections22
Heater voltage6.3 V6.3 V
Heater current0.45 A0.45 A
6GH8

Voltage Triode Pentode

Receiving Tubes

The database records 6U8 as a possible replacement for6GH8.

  • Parallel heater circuits only
  • No-warmup series circuits only
Specification6U8 replacementOriginal tube
Tube typeVoltage Radio Detector ConverterVoltage Triode Pentode
ConstructionPentode-TriodePentode-Triode
Base9AE9AE
SocketB9AB9A
Base pins99
Sections22
Heater voltage6.3 V6.3 V
Heater current0.45 A0.45 A
6GH8A

Voltage Triode Pentode

Receiving Tubes

The database records 6U8 as a possible replacement for6GH8A.

  • Parallel heater circuits only
  • No-warmup series circuits only
Specification6U8 replacementOriginal tube
Tube typeVoltage Radio Detector ConverterVoltage Triode Pentode
ConstructionPentode-TriodePentode-Triode
Base9AE9AE
SocketB9AB9A
Base pins99
Sections22
Heater voltage6.3 V6.3 V
Heater current0.45 A0.45 A
6GJ8

Voltage Triode Pentode

Receiving Tubes

The database records 6U8 as a possible replacement for6GJ8.

  • Parallel heater circuits only
Specification6U8 replacementOriginal tube
Tube typeVoltage Radio Detector ConverterVoltage Triode Pentode
ConstructionPentode-TriodePentode-Triode
Base9AENot recorded
SocketB9AB9A
Base pins99
Sections22
Heater voltage6.3 V6.3 V
Heater current0.45 A0.6 A
6KD8

Voltage Radio Detector Converter

Receiving Tubes

The database records 6U8 as a possible replacement for6KD8.

No special restrictions are recorded for this substitution.

Specification6U8 replacementOriginal tube
Tube typeVoltage Radio Detector ConverterVoltage Radio Detector Converter
ConstructionPentode-TriodePentode-Triode
Base9AE9AE
SocketB9AB9A
Base pins99
Sections22
Heater voltage6.3 V6.3 V
Heater current0.45 A0.4 A
6MQ8

Voltage Triode Pentode

Receiving Tubes

The database records 6U8 as a possible replacement for6MQ8.

  • Parallel heater circuits only
Specification6U8 replacementOriginal tube
Tube typeVoltage Radio Detector ConverterVoltage Triode Pentode
ConstructionPentode-TriodePentode-Triode
Base9AENot recorded
SocketB9AB9A
Base pins99
Sections22
Heater voltage6.3 V6.3 V
Heater current0.45 A0.535 A
6U8A

Voltage Radio Detector Converter

Receiving Tubes

The database records 6U8 as a possible replacement for6U8A.

  • Parallel heater circuits only
  • No-warmup series circuits only
Specification6U8 replacementOriginal tube
Tube typeVoltage Radio Detector ConverterVoltage Radio Detector Converter
ConstructionPentode-TriodePentode-Triode
Base9AEEIA 9AE
SocketB9AB9A
Base pins99
Sections22
Heater voltage6.3 V6.3 V
Heater current0.45 A0.45 A

Verify before substituting

Matching a base or heater voltage is not enough to prove that two tubes are interchangeable. Check pin connections, heater current, maximum ratings, bias requirements, warm-up behavior, and the equipment manufacturer’s service documentation before making a substitution.

View the complete 6U8 specifications →