Tube cross-reference
5998 alternatives, equivalents, and replacements
Review exact electrical variations and directional substitutions recorded for the 5998 power - triode. Compare core specifications and verify every restriction before using a replacement.
Where 5998 can be used as the replacement
In these recorded relationships, 5998 is the replacement tube. The listed original tubes are not automatically suitable as replacements for 5998.
Power - Triode
The database records 5998 as a possible replacement for421A.
No special restrictions are recorded for this substitution.
| Specification | 5998 replacement | Original tube |
|---|---|---|
| Tube type | Power - Triode | Power - Triode |
| Construction | Triode-Triode | Triode-Triode |
| Base | B8-11 | B8-11 |
| Socket | IO | UX4 |
| Base pins | 8 | 8 |
| Sections | 2 | 2 |
| Heater voltage | 6.3 V | 6.3 V |
| Heater current | 2.4 A | 2.4 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 5998 specifications →