What are the difference between step up audio transformer and an audio amplifier?

Question

What are the difference between step up audio transformer and an audio amplifier?

Answer 1

A setup transformer changes the impeadance there is not a change in power (other than minor loss ) between the input and output of the transformer.  

For the increase in voltage there is a corresponding decrease in current resulting in the relatively same power. You put 1 watt into a transformer you get basically 1 watt out.

The transformer is used when you want to convert a current to a useful voltage level. (or vise' versa)

An amplifier on the other hand,  does increase power between the input and output. A amp with a gain of 10 with an  input of 1/10th of a watt will output a 1watt signal.