frequency response can also be manually measured using this simple set up:
a scope would be even better as you can measure power at onset of clipping.
this signal gen has been with me for more than 20 years, and has undergone several mods, the dummy load resistors are 8ohms 50watts wirewound types, which i soak in watter when testing amps with 250 watts continuos average power per channel, both channels driven.
