We can see plots of THD+N (SINAD) vs. power at almost all power amplifier reviews. My question is, why we do not see THD (without noise component) vs. power plots as well?
My point is as follows - for many amplifiers, noise component may mask the distortion behaviour. Distortion profile is thus masked and it is difficult to say, from cumulative THD+N, what is happening in the amplifier. As an example, please see the measurements of my A250W class AB amplifier compared to my NC252MP. Both THD vs. power and THD+N vs. power plots are shown. Measuring BW = 22kHz. Load 4 ohm. Both amps have similar power, 200W+.
Please note how the "N" component in the THD+N plots masks and hides distortion profile and behaviour at various signal frequencies. Please also note that the 1kHz measurement gives the best results.
My point is as follows - for many amplifiers, noise component may mask the distortion behaviour. Distortion profile is thus masked and it is difficult to say, from cumulative THD+N, what is happening in the amplifier. As an example, please see the measurements of my A250W class AB amplifier compared to my NC252MP. Both THD vs. power and THD+N vs. power plots are shown. Measuring BW = 22kHz. Load 4 ohm. Both amps have similar power, 200W+.
Please note how the "N" component in the THD+N plots masks and hides distortion profile and behaviour at various signal frequencies. Please also note that the 1kHz measurement gives the best results.