Are the 1H4, 30, 99 electron tubes suitable for 1.2V plate supply?

The 1H4 should be retested. The 30, 99 are described on the Sylvania green manual as similar.


If memory is correct current was very low at very low plate potential. But so is with a 7586 Nuvistor, but the 7586 Pleiades V6 amplifier operates.


So it may be a good idea to retry 1H4 in real conditions, directly on the Pleiades V6 circuit operating with 1.2V.