Lord have mercy please don't use the word push when describing the capability of an amplifier. Watts is truly a useless specification out of context but in no context is there any difference between two equally speced amplifiers unless power is doubled. Amplifiers supply or source power. They do not push anything.
The loudspeaker is a weak, fickle, some might say floppy, creature that really doesn't know what it's about. Its (complex, very complex?) impedance varies all over the place and even is subject to things outside itself. The amplifier is the consummate, some might say brutal, voltage source, that forces its will upon the facile loudspeaker. This ultimate dominance is only attenuated by too thin speaker cables or crappy connectors. Alas, or maybe for the best, this relationship obeys conventional laws of physics and can be modeled accurately enough by assuming that the amplifier is a voltage source capable of a maximum voltage and maximum current (long-term thermal limits not withstanding). The loudspeaker can be assumed to be a resistor equal to its nominal impedance and any intervening transformers can assumed to be ideal, trading voltage for current in equal proportion perfectly. Forget about 70V, 100 V, whatever, and do the damn math. You'll be close enough.
Happy New Year. Hope we all get back to work and play soon.
--Frank
