Tube cross-reference
1B5 alternatives, equivalents, and replacements
Review exact electrical variations and directional substitutions recorded for the 1B5 voltage - triode (with diode, heptode or hexode). Compare core specifications and verify every restriction before using a replacement.
Exact variations of 1B5
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.
25S Voltage - Triode (with diode, heptode or hexode)
- Base
- Not recorded
- Socket
- UX6
- Base pins
- 6
- Sections
- 3
- Heater voltage
- 2 V
- Heater current
- 0.06 A
Replacement tubes for 1B5
The following tubes are recorded as possible replacements for 1B5. This direction does not establish that 1B5 can replace them.
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 | 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 | 6M | Not recorded |
| Socket | Not recorded | UX6 |
| Base pins | 6 | 6 |
| Sections | 3 | 3 |
| Heater voltage | 2 V | 2 V |
| Heater current | 0.06 A | 0.06 A |
Where 1B5 can be used as the replacement
In these recorded relationships, 1B5 is the replacement tube. The listed original tubes are not automatically suitable as replacements for 1B5.
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 | 1B5 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 | 6M | Not recorded |
| Socket | Not recorded | UX6 |
| 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 1B5 specifications →