8056
The 8056 is a low-voltage Nuvistor triode with a 6.3 V heater.
It is used in the 10A1, 422 and the 5T3. It can sometimes be replaced with a MPF102 FET.
The 8056 has a maximum plate-to-cathode voltage of 50V. Contrast this with another Nuvistor triode, the 7586, which has a maximum plate-to-cathode voltage of 110V. The 7586 and 8056 have the same pinout, but the two tubes are not interchangable since they have different voltage ratings. For example, in the front-end differential amplifiers of the 3A1, the plate voltage of the 7586 tubes, V113 and V123, is 55 V, and possibly a bit higher during warm-up. This exceeds the maximum plate voltage of the 8056, unless the 3A1 is modified for lower front-end plate voltages.
Links
- RCA 8056 Datasheet (PDF)
- Siemens 8056 Datasheet (PDF)
- RCA Nuvistor Reference (PDF)
- 8056 @ radiomuseum.org