Let me try , I could be all wet here , it's been a very long time !
Volts X Amps = Watts , the basic electrical power formula if I remember correctly .
Now you can get 100 watts with 20 volts and 5 amps - 20v X 5a = 100w , high voltage watts .
And you can get 100 watts with 5 volts and 20 amps - 5v X 20a = 100w , high amperage watts .
Correct ?
Further , really going out on a limb here ... I believe that the differences in these two examples is achieved within the power supply , ie. the output transformer , and the way that it is constructed .
I believe that the transformers' size and configuration will govern how much amperage is produced with a given amount of voltage . It takes a larger/heavier transformer to make big amperage as opposed to a smaller/lighter transformer to make small amperage .
Isn't this the reason that a 5.1 A/V receiver , with its smaller transformers , can weigh in at 25lbs. and a 2 channel amp , with larger transformers , can weigh in at 50lbs. while both putting out 100 watts/channel ? The A/V receiver will give you anemic sound under a tough load whereas the 2ch. amp is capable of giving sound with much more drive and authority .
These transformer primary and secondary windings , and their proportions , are the reason that when you cross the speaker cables on that receiver you get a light show and probably trip a breaker or blow a fuse . Do it on a welder and you can melt metal together . Both driven by a 120v/20a circuit .
Now I understand that the speaker will require X number of watts to operate that tough load . But it is the configuration of those watts that determines how that tough load is handled .
Am I making any sense here ? Kindness counts !