Tube cross-reference
25S alternatives, equivalents, and replacements
Review exact electrical variations and directional substitutions recorded for the 25S voltage - triode (with diode, heptode or hexode). Compare core specifications and verify every restriction before using a replacement.
Exact variations of 25S
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.
1B5 Voltage - Triode (with diode, heptode or hexode)
- Base
- 6M
- Socket
- Not recorded
- Base pins
- 6
- Sections
- 3
- Heater voltage
- 2 V
- Heater current
- 0.06 A
Replacement tubes for 25S
The following tubes are recorded as possible replacements for 25S. This direction does not establish that 25S can replace them.
Voltage - Triode (with diode, heptode or hexode)
The database records 1B5 as a possible replacement for25S.
No special restrictions are recorded for this substitution.
| Specification | Original tube | Replacement |
|---|---|---|
| Tube type | Voltage - Triode (with diode, heptode or hexode) | Voltage - Triode (with diode, heptode or hexode) |
| Construction | Diode-Diode-Triode | Diode-Diode-Triode |
| Base | Not recorded | 6M |
| Socket | UX6 | Not recorded |
| Base pins | 6 | 6 |
| Sections | 3 | 3 |
| Heater voltage | 2 V | 2 V |
| Heater current | 0.06 A | 0.06 A |
Where 25S can be used as the replacement
In these recorded relationships, 25S is the replacement tube. The listed original tubes are not automatically suitable as replacements for 25S.
Voltage - Triode (with diode, heptode or hexode)
The database records 25S as a possible replacement for1B5.
No special restrictions are recorded for this substitution.
| Specification | 25S replacement | Original tube |
|---|---|---|
| Tube type | Voltage - Triode (with diode, heptode or hexode) | Voltage - Triode (with diode, heptode or hexode) |
| Construction | Diode-Diode-Triode | Diode-Diode-Triode |
| Base | Not recorded | 6M |
| Socket | UX6 | Not recorded |
| Base pins | 6 | 6 |
| Sections | 3 | 3 |
| Heater voltage | 2 V | 2 V |
| Heater current | 0.06 A | 0.06 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 25S specifications →