amplification vs step-up

amplification and step-up both are nouns.

Word	Noun	Adjective	Verb	Adverb
amplification	Yes	No	No	No
step-up	Yes	No	No	No

As nouns, step-up is a hypernym of amplification; that is, step-up is a word with a broader meaning than amplification:

amplification: (electronics) the act of increasing voltage or power or current
step-up: the act of increasing something

Other hypernyms of amplification include increase.

amplification (noun)	step-up (noun)
(electronics) the act of increasing voltage or power or current	the act of increasing something
addition of extra material or illustration or clarifying detail
the amount of increase in signal power or voltage or current expressed as the ratio of output to input