Tube cross-reference
4BL8 alternatives, equivalents, and replacements
Review exact electrical variations and directional substitutions recorded for the 4BL8 voltage radio detector converter. Compare core specifications and verify every restriction before using a replacement.
Exact variations of 4BL8
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.
XCF80 Voltage Radio Detector Converter
- Base
- 9DC
- Socket
- B9A
- Base pins
- 9
- Sections
- 2
- Heater voltage
- 6.3 V
- Heater current
- 0.3 A
Replacement tubes for 4BL8
The following tubes are recorded as possible replacements for 4BL8. This direction does not establish that 4BL8 can replace them.
Voltage Radio Detector Converter
The database records XCF80 as a possible replacement for4BL8.
No special restrictions are recorded for this substitution.
| Specification | Original tube | Replacement |
|---|---|---|
| Tube type | Voltage Radio Detector Converter | Voltage Radio Detector Converter |
| Construction | Pentode-Triode | Pentode-Triode |
| Base | 9DC | 9DC |
| Socket | B9A | B9A |
| Base pins | 9 | 9 |
| Sections | 2 | 2 |
| Heater voltage | 4.6 V | 6.3 V |
| Heater current | 0.6 A | 0.3 A |
Voltage Triode Tetrode
The database records 5CQ8 as a possible replacement for4BL8.
- Not suitable for all circuits
| Specification | Original tube | Replacement |
|---|---|---|
| Tube type | Voltage Radio Detector Converter | Voltage Triode Tetrode |
| Construction | Pentode-Triode | Tetrode-Triode |
| Base | 9DC | 9GE |
| Socket | B9A | B9A |
| Base pins | 9 | 9 |
| Sections | 2 | 2 |
| Heater voltage | 4.6 V | 4.7 V |
| Heater current | 0.6 A | 0.6 A |
Voltage Radio Detector Converter
The database records 5EA8 as a possible replacement for4BL8.
No special restrictions are recorded for this substitution.
| Specification | Original tube | Replacement |
|---|---|---|
| Tube type | Voltage Radio Detector Converter | Voltage Radio Detector Converter |
| Construction | Pentode-Triode | Pentode-Triode |
| Base | 9DC | 9AE |
| Socket | B9A | B9A |
| Base pins | 9 | 9 |
| Sections | 2 | 2 |
| Heater voltage | 4.6 V | 4.7 V |
| Heater current | 0.6 A | 0.6 A |
Voltage Radio Detector Converter
The database records 5U8 as a possible replacement for4BL8.
No special restrictions are recorded for this substitution.
| Specification | Original tube | Replacement |
|---|---|---|
| Tube type | Voltage Radio Detector Converter | Voltage Radio Detector Converter |
| Construction | Pentode-Triode | Pentode-Triode |
| Base | 9DC | 9AE |
| Socket | B9A | B9A |
| Base pins | 9 | 9 |
| Sections | 2 | 2 |
| Heater voltage | 4.6 V | 5 V |
| Heater current | 0.6 A | 0.6 A |
Where 4BL8 can be used as the replacement
In these recorded relationships, 4BL8 is the replacement tube. The listed original tubes are not automatically suitable as replacements for 4BL8.
Voltage Radio Detector Converter
The database records 4BL8 as a possible replacement forXCF80.
No special restrictions are recorded for this substitution.
| Specification | 4BL8 replacement | Original tube |
|---|---|---|
| Tube type | Voltage Radio Detector Converter | Voltage Radio Detector Converter |
| Construction | Pentode-Triode | Pentode-Triode |
| Base | 9DC | 9DC |
| Socket | B9A | B9A |
| Base pins | 9 | 9 |
| Sections | 2 | 2 |
| Heater voltage | 4.6 V | 6.3 V |
| Heater current | 0.6 A | 0.3 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 4BL8 specifications →