Screen grid voltage at full B+?

[Rhodesplyr]

I look at it from the other end. I don't find that after a certain date they started to lower screen voltages, but that they started a power race and started raising +V voltages beyond (some cases WELL beyond) tube manual recommendations.

I don't disagree, but I think that there was a moment (around 1952 or so) where most amp designers seemed to collectively abandon the idea of running the screens directly from the B+ supply to the OPT. Hammond and Leslie continued making basically the same amps, but they now supplied the screens from a lower voltage stage. As the 50s continued, the output power race was on.

At the same time, I swear that I've seen a couple of 1950s amps (Premier 120) where the output power was purposefully limited, possibly to keep from blowing inexpensive speakers. Two Premier 120s I've worked on lacked cathode bypass caps on the output stage. They definitely had more power when bypasses were added, but I didn't ultimately add full-range bypasses because it seemed to me that doing so risked damaging the original speaker cones via excessive excursion. As far as I've heard, the amp power race got ahead of the speaker power race, especially around the early 60s.

Thinking about this Dumont amp from a phono console, might its output power have been limited by design to avoid acoustic feedback via the phono cartridge?