Tube cross-reference
8278 alternatives, equivalents, and replacements
Review exact electrical variations and directional substitutions recorded for the 8278 power - beam (not sweep). Compare core specifications and verify every restriction before using a replacement.
Exact variations of 8278
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.
EL503 Power - Pentode (NOT beam)
- Base
- 9C18
- Socket
- B9D
- Base pins
- 9
- Sections
- 1
- Heater voltage
- 6.3 V
- Heater current
- 1.05 A
Replacement tubes for 8278
The following tubes are recorded as possible replacements for 8278. This direction does not establish that 8278 can replace them.
Power - Pentode (NOT beam)
The database records EL503 as a possible replacement for8278.
No special restrictions are recorded for this substitution.
| Specification | Original tube | Replacement |
|---|---|---|
| Tube type | Power - Beam (NOT sweep) | Power - Pentode (NOT beam) |
| Construction | BeamPower | Pentode |
| Base | Not recorded | 9C18 |
| Socket | Not recorded | B9D |
| Base pins | Not recorded | 9 |
| Sections | 1 | 1 |
| Heater voltage | 6.3 V | 6.3 V |
| Heater current | 1.2 A | 1.05 A |
Where 8278 can be used as the replacement
In these recorded relationships, 8278 is the replacement tube. The listed original tubes are not automatically suitable as replacements for 8278.
Power - Pentode (NOT beam)
The database records 8278 as a possible replacement forEL503.
No special restrictions are recorded for this substitution.
| Specification | 8278 replacement | Original tube |
|---|---|---|
| Tube type | Power - Beam (NOT sweep) | Power - Pentode (NOT beam) |
| Construction | BeamPower | Pentode |
| Base | Not recorded | 9C18 |
| Socket | Not recorded | B9D |
| Base pins | Not recorded | 9 |
| Sections | 1 | 1 |
| Heater voltage | 6.3 V | 6.3 V |
| Heater current | 1.2 A | 1.05 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 8278 specifications →