Philco 41-280 question

[old_coot88]

Originally Posted by DavGoodlin

Old Coot, I must try that. I have a 240/120-6.3v filament transformer.

Um.. you're referring to single-ended application, right? Not sure that would work too good, because the line-voltage primary won't present high enough impedance to the AF output tube.
Whereas the center-tapped HV winding in a power xfmr is a usable match for p-p output tubes (and the split winding supplies flux cancellation).

Power trannys will pass decent broadcast-quality audio, with sharp roll-off above 5Khz or so. As a kid scrounging make-do parts for projects, i used them strapped back-to-back for Heising modulation in transmitters.