Step response can tell you everything you need to know about an amplifier, but criteria are not well defined. From what points do you measure rise time? 10 percent to 90 percent of max amplitude? How many overshoots? How big does the overshoot have to be to be counted? Etc. Etc. You can look at a scope trace and say "that's good" or "thats bad", but that is not very definitive.
Frequency response is not the same thing as step function response, but it is correlated. And a lot easier to measure. If an amp is 0.5 dB down at 100 Kc it probably has good step response.
Negative feedback is most often thought of as a way to reduce distortion, and it does do that. However, it also extends bandwidth, most notably in the case of pentode tube amp output transformers, where the feedback is provided by dedicated windings of the transformer that are connected to auxillary grids of the output tubes.
Frequency response is not the same thing as step function response, but it is correlated. And a lot easier to measure. If an amp is 0.5 dB down at 100 Kc it probably has good step response.
Negative feedback is most often thought of as a way to reduce distortion, and it does do that. However, it also extends bandwidth, most notably in the case of pentode tube amp output transformers, where the feedback is provided by dedicated windings of the transformer that are connected to auxillary grids of the output tubes.