Tube cross-reference
4BU8 alternatives, equivalents, and replacements
Review exact electrical variations and directional substitutions recorded for the 4BU8 voltage dual pentode. Compare core specifications and verify every restriction before using a replacement.
Exact variations of 4BU8
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.
4GS8 Voltage Dual Pentode
- Base
- Not recorded
- Socket
- B9A
- Base pins
- 9
- Sections
- 2
- Heater voltage
- 4.2 V
- Heater current
- 0.45 A
Replacement tubes for 4BU8
The following tubes are recorded as possible replacements for 4BU8. This direction does not establish that 4BU8 can replace them.
Voltage Dual Pentode
The database records 4GS8 as a possible replacement for4BU8.
No special restrictions are recorded for this substitution.
| Specification | Original tube | Replacement |
|---|---|---|
| Tube type | Voltage Dual Pentode | Voltage Dual Pentode |
| Construction | Pentode-Pentode | Pentode-Pentode |
| Base | Not recorded | Not recorded |
| Socket | B9A | B9A |
| Base pins | 9 | 9 |
| Sections | 2 | 2 |
| Heater voltage | 4.2 V | 4.2 V |
| Heater current | 0.45 A | 0.45 A |
Voltage Dual Pentode
The database records 4HS8 as a possible replacement for4BU8.
No special restrictions are recorded for this substitution.
| Specification | Original tube | Replacement |
|---|---|---|
| Tube type | Voltage Dual Pentode | Voltage Dual Pentode |
| Construction | Pentode-Pentode | Pentode-Pentode |
| Base | Not recorded | Not recorded |
| Socket | B9A | B9A |
| Base pins | 9 | 9 |
| Sections | 2 | 2 |
| Heater voltage | 4.2 V | 4.2 V |
| Heater current | 0.45 A | 0.45 A |
Voltage Radio Detector Converter
The database records 4KE8 as a possible replacement for4BU8.
No special restrictions are recorded for this substitution.
| Specification | Original tube | Replacement |
|---|---|---|
| Tube type | Voltage Dual Pentode | Voltage Radio Detector Converter |
| Construction | Pentode-Pentode | Pentode-Triode |
| Base | Not recorded | 9DC |
| Socket | B9A | B9A |
| Base pins | 9 | 9 |
| Sections | 2 | 2 |
| Heater voltage | 4.2 V | 4.5 V |
| Heater current | 0.45 A | 0.6 A |
Voltage Dual Pentode
The database records 4MK8 as a possible replacement for4BU8.
No special restrictions are recorded for this substitution.
| Specification | Original tube | Replacement |
|---|---|---|
| Tube type | Voltage Dual Pentode | Voltage Dual Pentode |
| Construction | Pentode-Pentode | Pentode-Pentode |
| Base | Not recorded | 9F6 |
| Socket | B9A | B9A |
| Base pins | 9 | 9 |
| Sections | 2 | 2 |
| Heater voltage | 4.2 V | 4.2 V |
| Heater current | 0.45 A | 0.45 A |
Where 4BU8 can be used as the replacement
In these recorded relationships, 4BU8 is the replacement tube. The listed original tubes are not automatically suitable as replacements for 4BU8.
Voltage Dual Pentode
The database records 4BU8 as a possible replacement for4GS8.
No special restrictions are recorded for this substitution.
| Specification | 4BU8 replacement | Original tube |
|---|---|---|
| Tube type | Voltage Dual Pentode | Voltage Dual Pentode |
| Construction | Pentode-Pentode | Pentode-Pentode |
| Base | Not recorded | Not recorded |
| Socket | B9A | B9A |
| Base pins | 9 | 9 |
| Sections | 2 | 2 |
| Heater voltage | 4.2 V | 4.2 V |
| Heater current | 0.45 A | 0.45 A |
Voltage Dual Pentode
The database records 4BU8 as a possible replacement for4HS8.
No special restrictions are recorded for this substitution.
| Specification | 4BU8 replacement | Original tube |
|---|---|---|
| Tube type | Voltage Dual Pentode | Voltage Dual Pentode |
| Construction | Pentode-Pentode | Pentode-Pentode |
| Base | Not recorded | Not recorded |
| Socket | B9A | B9A |
| Base pins | 9 | 9 |
| Sections | 2 | 2 |
| Heater voltage | 4.2 V | 4.2 V |
| Heater current | 0.45 A | 0.45 A |
Voltage Dual Pentode
The database records 4BU8 as a possible replacement for4MK8.
No special restrictions are recorded for this substitution.
| Specification | 4BU8 replacement | Original tube |
|---|---|---|
| Tube type | Voltage Dual Pentode | Voltage Dual Pentode |
| Construction | Pentode-Pentode | Pentode-Pentode |
| Base | Not recorded | 9F6 |
| Socket | B9A | B9A |
| Base pins | 9 | 9 |
| Sections | 2 | 2 |
| Heater voltage | 4.2 V | 4.2 V |
| Heater current | 0.45 A | 0.45 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 4BU8 specifications →