[Milsurplus] BC-348-C Modifications

[Ian Wilson]

The 6AC7 has more than one mode of operation. To quote someone else's
posting on Glowbugs:

Footnotes in the specs mention that a fixed-voltage screen supply
yields a sharp-cutoff characteristic, while series screen resistance
produces an "..Extended cutoff characteristic where gain is controlled by
grid bias...."

So it may not be necessary to replace the 6AC7 just for the AVC.

73, ian K3IMW