Tube cross-reference
6391 alternatives, equivalents, and replacements
Review exact electrical variations and directional substitutions recorded for the 6391 voltage pentode. Compare core specifications and verify every restriction before using a replacement.
Replacement tubes for 6391
The following tubes are recorded as possible replacements for 6391. This direction does not establish that 6391 can replace them.
Voltage Pentode
The database records EF74 as a possible replacement for6391.
No special restrictions are recorded for this substitution.
| Specification | Original tube | Replacement |
|---|---|---|
| Tube type | Voltage Pentode | Voltage Pentode |
| Construction | Pentode | Pentode |
| Base | 6391 | B8D/F |
| Socket | SUBMINIATURE8 | WIRE8 |
| Base pins | 8 | 8 |
| Sections | 1 | 1 |
| Heater voltage | 6.3 V | 6.3 V |
| Heater current | 0.2 A | 0.2 A |
Where 6391 can be used as the replacement
In these recorded relationships, 6391 is the replacement tube. The listed original tubes are not automatically suitable as replacements for 6391.
Voltage Pentode
The database records 6391 as a possible replacement forEF74.
No special restrictions are recorded for this substitution.
| Specification | 6391 replacement | Original tube |
|---|---|---|
| Tube type | Voltage Pentode | Voltage Pentode |
| Construction | Pentode | Pentode |
| Base | 6391 | B8D/F |
| Socket | SUBMINIATURE8 | WIRE8 |
| Base pins | 8 | 8 |
| Sections | 1 | 1 |
| Heater voltage | 6.3 V | 6.3 V |
| Heater current | 0.2 A | 0.2 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 6391 specifications →