[ARC5] 10 meter BC-454 - yet more

[Ian Wilson]

The 6AC7, according to the data sheet, is either sharp cutoff or remote
cutoff depending on how you control the screen grid:

*When a fixed screen voltage is used, as shown in condition 1, a
sharp-cutoff*
*characteristic is obtained.*
*
*
*When a screen resistor is used, as shown in condition 2, an extended cutoff
*
*characteristic is obtained which may be utilized in applications where the*
*gain is controlled by variation of the grid bias.*

(GE data sheet).
Condition 1: 150v fixed screen voltage.
Condition 2: 60k screen resistor to +300v.

73, ian K3IMW