Tube cross-reference
12FX8 alternatives, equivalents, and replacements
Review exact electrical variations and directional substitutions recorded for the 12FX8 voltage - triode (with diode, heptode or hexode). Compare core specifications and verify every restriction before using a replacement.
Replacement tubes for 12FX8
The following tubes are recorded as possible replacements for 12FX8. This direction does not establish that 12FX8 can replace them.
Voltage - Triode (with diode, heptode or hexode)
The database records 12FX8A as a possible replacement for12FX8.
No special restrictions are recorded for this substitution.
| Specification | Original tube | Replacement |
|---|---|---|
| Tube type | Voltage - Triode (with diode, heptode or hexode) | Voltage - Triode (with diode, heptode or hexode) |
| Construction | Heptode-Triode | Heptode-Triode |
| Base | 9KV | 9KV |
| Socket | B9A | B9A |
| Base pins | 9 | 9 |
| Sections | 2 | 2 |
| Heater voltage | 12.6 V | 12.6 V |
| Heater current | 0.27 A | 0.27 A |
Where 12FX8 can be used as the replacement
In these recorded relationships, 12FX8 is the replacement tube. The listed original tubes are not automatically suitable as replacements for 12FX8.
Voltage - Triode (with diode, heptode or hexode)
The database records 12FX8 as a possible replacement for12FX8A.
No special restrictions are recorded for this substitution.
| Specification | 12FX8 replacement | Original tube |
|---|---|---|
| Tube type | Voltage - Triode (with diode, heptode or hexode) | Voltage - Triode (with diode, heptode or hexode) |
| Construction | Heptode-Triode | Heptode-Triode |
| Base | 9KV | 9KV |
| Socket | B9A | B9A |
| Base pins | 9 | 9 |
| Sections | 2 | 2 |
| Heater voltage | 12.6 V | 12.6 V |
| Heater current | 0.27 A | 0.27 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 12FX8 specifications →