One of the most important points is checking the response speed. When highly accurate output waveform is needed, it is important to confirm whether or not the amplifier offers sufficient response speed.
It is definitely necessary to have "higher frequency compared to the actual value at operation". In other words, as for sine wave, you need to select the power supply with the frequency three to five times higher than the actual value in use. Regarding short wave, you should secure the power supply with the frequency higher than the actual use by nearly ten times.