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Tube cross-reference

6LM8 alternatives, equivalents, and replacements

Review exact electrical variations and directional substitutions recorded for the 6LM8 voltage triode pentode. Compare core specifications and verify every restriction before using a replacement.

Replacement tubes for 6LM8

The following tubes are recorded as possible replacements for 6LM8. This direction does not establish that 6LM8 can replace them.

6AX8

Voltage Pentode - Sharp Cutoff (single)

Receiving Tubes

The database records 6AX8 as a possible replacement for6LM8.

No special restrictions are recorded for this substitution.

SpecificationOriginal tubeReplacement
Tube typeVoltage Triode PentodeVoltage Pentode - Sharp Cutoff (single)
ConstructionPentode-TriodePentode-Triode
Base9AE9AE
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 for6LM8.

  • Not suitable for all circuits
SpecificationOriginal tubeReplacement
Tube typeVoltage Triode PentodeVoltage Radio Detector Converter
ConstructionPentode-TriodeTetrode-Triode
Base9AE9GE
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 6GH8 as a possible replacement for6LM8.

No special restrictions are recorded for this substitution.

SpecificationOriginal tubeReplacement
Tube typeVoltage Triode PentodeVoltage 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 6GH8A as a possible replacement for6LM8.

No special restrictions are recorded for this substitution.

SpecificationOriginal tubeReplacement
Tube typeVoltage Triode PentodeVoltage Triode Pentode
ConstructionPentode-TriodePentode-Triode
Base9AE9AE
SocketB9AB9A
Base pins99
Sections22
Heater voltage6.3 V6.3 V
Heater current0.45 A0.45 A

Where 6LM8 can be used as the replacement

In these recorded relationships, 6LM8 is the replacement tube. The listed original tubes are not automatically suitable as replacements for 6LM8.

6AX8

Voltage Pentode - Sharp Cutoff (single)

Receiving Tubes

The database records 6LM8 as a possible replacement for6AX8.

No special restrictions are recorded for this substitution.

Specification6LM8 replacementOriginal tube
Tube typeVoltage Triode PentodeVoltage 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 6LM8 as a possible replacement for6GH8.

  • Parallel heater circuits only
  • No-warmup series circuits only
Specification6LM8 replacementOriginal tube
Tube typeVoltage Triode PentodeVoltage 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 6LM8 as a possible replacement for6GH8A.

  • Parallel heater circuits only
  • No-warmup series circuits only
Specification6LM8 replacementOriginal tube
Tube typeVoltage Triode PentodeVoltage Triode Pentode
ConstructionPentode-TriodePentode-Triode
Base9AE9AE
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 6LM8 specifications →