Tube cross-reference
56 alternatives, equivalents, and replacements
Review exact electrical variations and directional substitutions recorded for the 56 voltage - triode (single). Compare core specifications and verify every restriction before using a replacement.
Exact variations of 56
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.
Replacement tubes for 56
The following tubes are recorded as possible replacements for 56. This direction does not establish that 56 can replace them.
Voltage - Triode (single)
The database records 27 as a possible replacement for56.
No special restrictions are recorded for this substitution.
| Specification | Original tube | Replacement |
|---|---|---|
| Tube type | Voltage - Triode (single) | Voltage - Triode (single) |
| Construction | Triode | Triode |
| Base | 5A | 5A |
| Socket | UX5 | UX5 |
| Base pins | 5 | 5 |
| Sections | 1 | 1 |
| Heater voltage | 2.5 V | 2.5 V |
| Heater current | 1 A | 1.75 A |
Where 56 can be used as the replacement
In these recorded relationships, 56 is the replacement tube. The listed original tubes are not automatically suitable as replacements for 56.
Voltage - Triode (single)
The database records 56 as a possible replacement for27.
No special restrictions are recorded for this substitution.
| Specification | 56 replacement | Original tube |
|---|---|---|
| Tube type | Voltage - Triode (single) | Voltage - Triode (single) |
| Construction | Triode | Triode |
| Base | 5A | 5A |
| Socket | UX5 | UX5 |
| Base pins | 5 | 5 |
| Sections | 1 | 1 |
| Heater voltage | 2.5 V | 2.5 V |
| Heater current | 1 A | 1.75 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 56 specifications →