Tube cross-reference
6R4 alternatives, equivalents, and replacements
Review exact electrical variations and directional substitutions recorded for the 6R4 voltage - triode (single high frequency). Compare core specifications and verify every restriction before using a replacement.
Exact variations of 6R4
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.
EC81 Power - Triode Single (under 10W)
- Base
- Not recorded
- Socket
- B9A
- Base pins
- 9
- Sections
- 1
- Heater voltage
- 6.3 V
- Heater current
- 0.24 A
Replacement tubes for 6R4
The following tubes are recorded as possible replacements for 6R4. This direction does not establish that 6R4 can replace them.
Power - Triode Single (under 10W)
The database records EC81 as a possible replacement for6R4.
No special restrictions are recorded for this substitution.
| Specification | Original tube | Replacement |
|---|---|---|
| Tube type | Voltage - Triode (single high frequency) | Power - Triode Single (under 10W) |
| Construction | Triode | Triode |
| Base | Not recorded | Not recorded |
| Socket | Not recorded | B9A |
| Base pins | Not recorded | 9 |
| Sections | 1 | 1 |
| Heater voltage | 6.3 V | 6.3 V |
| Heater current | 0.24 A | 0.24 A |
Where 6R4 can be used as the replacement
In these recorded relationships, 6R4 is the replacement tube. The listed original tubes are not automatically suitable as replacements for 6R4.
Power - Triode Single (under 10W)
The database records 6R4 as a possible replacement forEC81.
No special restrictions are recorded for this substitution.
| Specification | 6R4 replacement | Original tube |
|---|---|---|
| Tube type | Voltage - Triode (single high frequency) | Power - Triode Single (under 10W) |
| Construction | Triode | Triode |
| Base | Not recorded | Not recorded |
| Socket | Not recorded | B9A |
| Base pins | Not recorded | 9 |
| Sections | 1 | 1 |
| Heater voltage | 6.3 V | 6.3 V |
| Heater current | 0.24 A | 0.24 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 6R4 specifications →