Tube cross-reference
OA3 alternatives, equivalents, and replacements
Review exact electrical variations and directional substitutions recorded for the OA3 voltage regulator. Compare core specifications and verify every restriction before using a replacement.
Where OA3 can be used as the replacement
In these recorded relationships, OA3 is the replacement tube. The listed original tubes are not automatically suitable as replacements for OA3.
Voltage Regulator
The database records OA3 as a possible replacement forVR75.
No special restrictions are recorded for this substitution.
| Specification | OA3 replacement | Original tube |
|---|---|---|
| Tube type | Voltage Regulator | Voltage Regulator |
| Construction | VoltageRegulator | VoltageRegulator |
| Base | 4AJ | 4AJ |
| Socket | IO | Not recorded |
| Base pins | 8 | 4 |
| Sections | 1 | 1 |
| Heater voltage | Not recorded | Not recorded |
| Heater current | Not recorded | Not recorded |
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 OA3 specifications →