SINAD chart is only a measurment at 5W/4ohm with a 1kHz tone, am I right?
How about an amplifier with, lets say, a SINAD of 80db but with a lot more headroom. It would land right in the middle of the chart.
Newbies would say it's a so-so amp comparing to a 106db one (Topping PA5 for example)
But...