Tube cross-reference
4BC8 alternatives, equivalents, and replacements
Review exact electrical variations and directional substitutions recorded for the 4BC8 voltage - dual triode (similar high frequency). Compare core specifications and verify every restriction before using a replacement.
Exact variations of 4BC8
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.
4RHH2 Voltage - Dual Triode (similar high frequency)
- Base
- E9-1
- Socket
- Not recorded
- Base pins
- 9
- Sections
- 2
- Heater voltage
- 4.2 V
- Heater current
- 0.6 A
Replacement tubes for 4BC8
The following tubes are recorded as possible replacements for 4BC8. This direction does not establish that 4BC8 can replace them.
Voltage - Dual Triode (similar high frequency)
The database records 4BQ7A as a possible replacement for4BC8.
No special restrictions are recorded for this substitution.
| Specification | Original tube | Replacement |
|---|---|---|
| Tube type | Voltage - Dual Triode (similar high frequency) | Voltage - Dual Triode (similar high frequency) |
| Construction | Triode-Triode | Triode-Triode |
| Base | 9AJ | 9AY |
| Socket | B9A | B9A |
| Base pins | 9 | 9 |
| Sections | 2 | 2 |
| Heater voltage | 4.2 V | 4.2 V |
| Heater current | 0.6 A | 0.6 A |
Voltage - Dual Triode (similar high frequency)
The database records 4BS8 as a possible replacement for4BC8.
No special restrictions are recorded for this substitution.
| Specification | Original tube | Replacement |
|---|---|---|
| Tube type | Voltage - Dual Triode (similar high frequency) | Voltage - Dual Triode (similar high frequency) |
| Construction | Triode-Triode | Triode-Triode |
| Base | 9AJ | Not recorded |
| Socket | B9A | B9A |
| Base pins | 9 | 9 |
| Sections | 2 | 2 |
| Heater voltage | 4.2 V | 4.5 V |
| Heater current | 0.6 A | 0.6 A |
Voltage - Dual Triode (similar high frequency)
The database records 4BZ7 as a possible replacement for4BC8.
No special restrictions are recorded for this substitution.
| Specification | Original tube | Replacement |
|---|---|---|
| Tube type | Voltage - Dual Triode (similar high frequency) | Voltage - Dual Triode (similar high frequency) |
| Construction | Triode-Triode | Triode-Triode |
| Base | 9AJ | 9AJ |
| Socket | B9A | B9A |
| Base pins | 9 | 9 |
| Sections | 2 | 2 |
| Heater voltage | 4.2 V | 4.2 V |
| Heater current | 0.6 A | 0.6 A |
Voltage - Dual Triode (similar high frequency)
The database records 5BK7A as a possible replacement for4BC8.
No special restrictions are recorded for this substitution.
| Specification | Original tube | Replacement |
|---|---|---|
| Tube type | Voltage - Dual Triode (similar high frequency) | Voltage - Dual Triode (similar high frequency) |
| Construction | Triode-Triode | Triode-Triode |
| Base | 9AJ | 9AJ |
| Socket | B9A | B9A |
| Base pins | 9 | 9 |
| Sections | 2 | 2 |
| Heater voltage | 4.2 V | 4.7 V |
| Heater current | 0.6 A | 0.6 A |
Where 4BC8 can be used as the replacement
In these recorded relationships, 4BC8 is the replacement tube. The listed original tubes are not automatically suitable as replacements for 4BC8.
Voltage - Dual Triode (similar high frequency)
The database records 4BC8 as a possible replacement for4BQ7A.
No special restrictions are recorded for this substitution.
| Specification | 4BC8 replacement | Original tube |
|---|---|---|
| Tube type | Voltage - Dual Triode (similar high frequency) | Voltage - Dual Triode (similar high frequency) |
| Construction | Triode-Triode | Triode-Triode |
| Base | 9AJ | 9AY |
| Socket | B9A | B9A |
| Base pins | 9 | 9 |
| Sections | 2 | 2 |
| Heater voltage | 4.2 V | 4.2 V |
| Heater current | 0.6 A | 0.6 A |
Voltage - Dual Triode (similar high frequency)
The database records 4BC8 as a possible replacement for4BS8.
No special restrictions are recorded for this substitution.
| Specification | 4BC8 replacement | Original tube |
|---|---|---|
| Tube type | Voltage - Dual Triode (similar high frequency) | Voltage - Dual Triode (similar high frequency) |
| Construction | Triode-Triode | Triode-Triode |
| Base | 9AJ | Not recorded |
| Socket | B9A | B9A |
| Base pins | 9 | 9 |
| Sections | 2 | 2 |
| Heater voltage | 4.2 V | 4.5 V |
| Heater current | 0.6 A | 0.6 A |
Voltage - Dual Triode (similar high frequency)
The database records 4BC8 as a possible replacement for4BZ7.
No special restrictions are recorded for this substitution.
| Specification | 4BC8 replacement | Original tube |
|---|---|---|
| Tube type | Voltage - Dual Triode (similar high frequency) | Voltage - Dual Triode (similar high frequency) |
| Construction | Triode-Triode | Triode-Triode |
| Base | 9AJ | 9AJ |
| Socket | B9A | B9A |
| Base pins | 9 | 9 |
| Sections | 2 | 2 |
| Heater voltage | 4.2 V | 4.2 V |
| Heater current | 0.6 A | 0.6 A |
Voltage - Dual Triode (similar high frequency)
The database records 4BC8 as a possible replacement for5BK7A.
No special restrictions are recorded for this substitution.
| Specification | 4BC8 replacement | Original tube |
|---|---|---|
| Tube type | Voltage - Dual Triode (similar high frequency) | Voltage - Dual Triode (similar high frequency) |
| Construction | Triode-Triode | Triode-Triode |
| Base | 9AJ | 9AJ |
| Socket | B9A | B9A |
| Base pins | 9 | 9 |
| Sections | 2 | 2 |
| Heater voltage | 4.2 V | 4.7 V |
| Heater current | 0.6 A | 0.6 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 4BC8 specifications →