Tube cross-reference
78 alternatives, equivalents, and replacements
Review exact electrical variations and directional substitutions recorded for the 78 voltage pentode - remote cutoff (single). Compare core specifications and verify every restriction before using a replacement.
Replacement tubes for 78
The following tubes are recorded as possible replacements for 78. This direction does not establish that 78 can replace them.
Voltage Radio Detector Converter
The database records 6D6 as a possible replacement for78.
No special restrictions are recorded for this substitution.
| Specification | Original tube | Replacement |
|---|---|---|
| Tube type | Voltage Pentode - Remote Cutoff (single) | Voltage Radio Detector Converter |
| Construction | Pentode | Pentode |
| Base | 8F | 6F |
| Socket | UX6 | UX6 |
| Base pins | 6 | 6 |
| Sections | 1 | 1 |
| Heater voltage | 6.3 V | 6.3 V |
| Heater current | 0.3 A | 0.3 A |
Where 78 can be used as the replacement
In these recorded relationships, 78 is the replacement tube. The listed original tubes are not automatically suitable as replacements for 78.
Voltage Radio Detector Converter
The database records 78 as a possible replacement for6D6.
No special restrictions are recorded for this substitution.
| Specification | 78 replacement | Original tube |
|---|---|---|
| Tube type | Voltage Pentode - Remote Cutoff (single) | Voltage Radio Detector Converter |
| Construction | Pentode | Pentode |
| Base | 8F | 6F |
| Socket | UX6 | UX6 |
| Base pins | 6 | 6 |
| Sections | 1 | 1 |
| Heater voltage | 6.3 V | 6.3 V |
| Heater current | 0.3 A | 0.3 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 78 specifications →