Tube cross-reference
21DAP4 alternatives, equivalents, and replacements
Review exact electrical variations and directional substitutions recorded for the 21DAP4 specialized - cathode ray. Compare core specifications and verify every restriction before using a replacement.
Replacement tubes for 21DAP4
The following tubes are recorded as possible replacements for 21DAP4. This direction does not establish that 21DAP4 can replace them.
Specialized - Cathode Ray
The database records 21DMP4 as a possible replacement for21DAP4.
No special restrictions are recorded for this substitution.
| Specification | Original tube | Replacement |
|---|---|---|
| Tube type | Specialized - Cathode Ray | Specialized - Cathode Ray |
| Construction | CathodeRay | CathodeRay |
| Base | Not recorded | 8HR |
| Socket | DUODECAL5 | NEOEIGHTAR7 |
| Base pins | Not recorded | 8 |
| Sections | 1 | 1 |
| 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 21DAP4 specifications →