dave wrote:
You forgot to turn on the BFO. BFO level is frequently too low for
demodding SSB hence the need to reduce RF gain.

Yep, easy to see from the jpeg that there's a BFO present.

I seem to remember having to repair an old KnightKit
tube radio that worked OK otherwise - bad capacitor in
the BFO. Person I bought it from didn't know what one
was so he wouldn't have had any reason to know it wasn't
working when he owned it.