R
Raoul Duke
Thanks for the explanation.Not exactly. With respect to audio amplifiers, tubes create gain by magnifying voltage swing. Transistor amplifiers work primarily by increasing current.
So in that beast of a 90 volt battery, you'd have 60 tiny 1.5 volt carbon zinc cells, wired in series. There's high voltage, but low current. In all likelihood, the absolute amperage available from the B+ supply, was less than that available in today's smartphones