Tube cross-reference
U78 alternatives, equivalents, and replacements
Review exact electrical variations and directional substitutions recorded for the U78 rectifier - full wave. Compare core specifications and verify every restriction before using a replacement.
Replacement tubes for U78
The following tubes are recorded as possible replacements for U78. This direction does not establish that U78 can replace them.
Rectifier - Full Wave
The database records 6X4 as a possible replacement forU78.
- Parallel heater circuits only
| Specification | Original tube | Replacement |
|---|---|---|
| Tube type | Rectifier - Full Wave | Rectifier - Full Wave |
| Construction | Rectifier-Rectifier | Rectifier-Rectifier |
| Base | Not recorded | 5S |
| Socket | B7G | B7G |
| Base pins | Not recorded | 7 |
| Sections | 2 | 2 |
| Heater voltage | 6.3 V | 6.3 V |
| Heater current | 0.6 A | 0.6 A |
Where U78 can be used as the replacement
In these recorded relationships, U78 is the replacement tube. The listed original tubes are not automatically suitable as replacements for U78.
Rectifier - Full Wave
The database records U78 as a possible replacement for5993.
No special restrictions are recorded for this substitution.
| Specification | U78 replacement | Original tube |
|---|---|---|
| Tube type | Rectifier - Full Wave | Rectifier - Full Wave |
| Construction | Rectifier-Rectifier | Rectifier-Rectifier |
| Base | Not recorded | Not recorded |
| Socket | B7G | B9A |
| Base pins | Not recorded | 9 |
| Sections | 2 | 2 |
| Heater voltage | 6.3 V | 6 V |
| Heater current | 0.6 A | 0.8 A |
Rectifier - Full Wave
The database records U78 as a possible replacement for6063.
No special restrictions are recorded for this substitution.
| Specification | U78 replacement | Original tube |
|---|---|---|
| Tube type | Rectifier - Full Wave | Rectifier - Full Wave |
| Construction | Rectifier-Rectifier | Rectifier-Rectifier |
| Base | Not recorded | 5BS |
| Socket | B7G | B7G |
| Base pins | Not recorded | 7 |
| Sections | 2 | 2 |
| Heater voltage | 6.3 V | 6.3 V |
| Heater current | 0.6 A | 0.6 A |
Rectifier - Full Wave
The database records U78 as a possible replacement for6202.
No special restrictions are recorded for this substitution.
| Specification | U78 replacement | Original tube |
|---|---|---|
| Tube type | Rectifier - Full Wave | Rectifier - Full Wave |
| Construction | Rectifier-Rectifier | Rectifier-Rectifier |
| Base | Not recorded | E7-1 |
| Socket | B7G | B7G |
| Base pins | Not recorded | 7 |
| Sections | 2 | 2 |
| Heater voltage | 6.3 V | 6.3 V |
| Heater current | 0.6 A | 0.6 A |
Rectifier - Full Wave
The database records U78 as a possible replacement for6203.
No special restrictions are recorded for this substitution.
| Specification | U78 replacement | Original tube |
|---|---|---|
| Tube type | Rectifier - Full Wave | Rectifier - Full Wave |
| Construction | Rectifier-Rectifier | Rectifier-Rectifier |
| Base | Not recorded | E9-1 |
| Socket | B7G | B9A |
| Base pins | Not recorded | 9 |
| Sections | 2 | 2 |
| Heater voltage | 6.3 V | 6.3 V |
| Heater current | 0.6 A | 0.9 A |
Rectifier - Full Wave
The database records U78 as a possible replacement for6X4.
- Parallel heater circuits only
| Specification | U78 replacement | Original tube |
|---|---|---|
| Tube type | Rectifier - Full Wave | Rectifier - Full Wave |
| Construction | Rectifier-Rectifier | Rectifier-Rectifier |
| Base | Not recorded | 5S |
| Socket | B7G | B7G |
| Base pins | Not recorded | 7 |
| Sections | 2 | 2 |
| Heater voltage | 6.3 V | 6.3 V |
| Heater current | 0.6 A | 0.6 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 U78 specifications →