Tube cross-reference
420A alternatives, equivalents, and replacements
Review exact electrical variations and directional substitutions recorded for the 420A voltage - dual triode (similar). Compare core specifications and verify every restriction before using a replacement.
Exact variations of 420A
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.
5755 Voltage - Dual Triode (similar)
- Base
- Not recorded
- Socket
- B9A
- Base pins
- 9
- Sections
- 2
- Heater voltage
- 6.3 V
- Heater current
- 0.36 A
Replacement tubes for 420A
The following tubes are recorded as possible replacements for 420A. This direction does not establish that 420A can replace them.
Voltage - Dual Triode (similar)
The database records 5755 as a possible replacement for420A.
No special restrictions are recorded for this substitution.
| Specification | Original tube | Replacement |
|---|---|---|
| Tube type | Voltage - Dual Triode (similar) | Voltage - Dual Triode (similar) |
| Construction | Triode-Triode | Triode-Triode |
| Base | Not recorded | Not recorded |
| Socket | UX4 | B9A |
| Base pins | 9 | 9 |
| Sections | 2 | 2 |
| Heater voltage | 6.3 V | 6.3 V |
| Heater current | 0.36 A | 0.36 A |
Where 420A can be used as the replacement
In these recorded relationships, 420A is the replacement tube. The listed original tubes are not automatically suitable as replacements for 420A.
Voltage - Dual Triode (similar)
The database records 420A as a possible replacement for5755.
No special restrictions are recorded for this substitution.
| Specification | 420A replacement | Original tube |
|---|---|---|
| Tube type | Voltage - Dual Triode (similar) | Voltage - Dual Triode (similar) |
| Construction | Triode-Triode | Triode-Triode |
| Base | Not recorded | Not recorded |
| Socket | UX4 | B9A |
| Base pins | 9 | 9 |
| Sections | 2 | 2 |
| Heater voltage | 6.3 V | 6.3 V |
| Heater current | 0.36 A | 0.36 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 420A specifications →