Tube cross-reference
6BL4 alternatives, equivalents, and replacements
Review exact electrical variations and directional substitutions recorded for the 6BL4 rectifier - damper diode. Compare core specifications and verify every restriction before using a replacement.
Replacement tubes for 6BL4
The following tubes are recorded as possible replacements for 6BL4. This direction does not establish that 6BL4 can replace them.
Rectifier - Damper Diode
The database records 6AU4GTA as a possible replacement for6BL4.
- Parallel heater circuits only
| Specification | Original tube | Replacement |
|---|---|---|
| Tube type | Rectifier - Damper Diode | Rectifier - Damper Diode |
| Construction | Rectifier | Rectifier |
| Base | 8GB | 4CG |
| Socket | Not recorded | IO |
| Base pins | 8 | 8 |
| Sections | 1 | 1 |
| Heater voltage | 6.3 V | 6.3 V |
| Heater current | 3 A | 1.8 A |
Rectifier - Damper Diode
The database records 6CQ4 as a possible replacement for6BL4.
- Parallel heater circuits only
| Specification | Original tube | Replacement |
|---|---|---|
| Tube type | Rectifier - Damper Diode | Rectifier - Damper Diode |
| Construction | Rectifier | Rectifier |
| Base | 8GB | 4L6 |
| Socket | Not recorded | B9A |
| Base pins | 8 | 9 |
| Sections | 1 | 1 |
| Heater voltage | 6.3 V | 6.3 V |
| Heater current | 3 A | 1.6 A |
Rectifier - Damper Diode
The database records 6DM4A as a possible replacement for6BL4.
- Parallel heater circuits only
| Specification | Original tube | Replacement |
|---|---|---|
| Tube type | Rectifier - Damper Diode | Rectifier - Damper Diode |
| Construction | Rectifier | Rectifier |
| Base | 8GB | 4CG |
| Socket | Not recorded | IO |
| Base pins | 8 | 8 |
| Sections | 1 | 1 |
| Heater voltage | 6.3 V | 6.3 V |
| Heater current | 3 A | 1.2 A |
Rectifier - Damper Diode
The database records 6DT4 as a possible replacement for6BL4.
- Parallel heater circuits only
| Specification | Original tube | Replacement |
|---|---|---|
| Tube type | Rectifier - Damper Diode | Rectifier - Damper Diode |
| Construction | Rectifier | Rectifier |
| Base | 8GB | 4CG |
| Socket | Not recorded | IO |
| Base pins | 8 | 5 |
| Sections | 1 | 1 |
| Heater voltage | 6.3 V | 6.3 V |
| Heater current | 3 A | 1.2 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 6BL4 specifications →