Tube cross-reference
409A alternatives, equivalents, and replacements
Review exact electrical variations and directional substitutions recorded for the 409A voltage pentode. Compare core specifications and verify every restriction before using a replacement.
Replacement tubes for 409A
The following tubes are recorded as possible replacements for 409A. This direction does not establish that 409A can replace them.
Voltage Pentode - Sharp Cutoff (single)
The database records 6AS6 as a possible replacement for409A.
No special restrictions are recorded for this substitution.
| Specification | Original tube | Replacement |
|---|---|---|
| Tube type | Voltage Pentode | Voltage Pentode - Sharp Cutoff (single) |
| Construction | Pentode | Pentode |
| Base | E7-1 | E7-1 |
| Socket | B7G | B7G |
| Base pins | 7 | 7 |
| Sections | 1 | 1 |
| Heater voltage | 6.3 V | 6.3 V |
| Heater current | 0.175 A | 0.175 A |
Where 409A can be used as the replacement
In these recorded relationships, 409A is the replacement tube. The listed original tubes are not automatically suitable as replacements for 409A.
Voltage Pentode - Sharp Cutoff (single)
The database records 409A as a possible replacement for6AS6.
No special restrictions are recorded for this substitution.
| Specification | 409A replacement | Original tube |
|---|---|---|
| Tube type | Voltage Pentode | Voltage Pentode - Sharp Cutoff (single) |
| Construction | Pentode | Pentode |
| Base | E7-1 | E7-1 |
| Socket | B7G | B7G |
| Base pins | 7 | 7 |
| Sections | 1 | 1 |
| Heater voltage | 6.3 V | 6.3 V |
| Heater current | 0.175 A | 0.175 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 409A specifications →