[Mondial]

Resistors 53 and 54 are bias resistors for the 41 output tubes. They don't affect the power output but they may alter the low frequency response. The 1 meg resistors will increase the bass slightly, which might have been necessary with a smaller speaker.

Same thing with the caps across the output transformer. These tune the output circuit affecting the high freq response. The smaller speaker will reproduce the high freqs better so the extra and larger value caps rolled off the treble to compensate.