Picking up on the turn/off pops on Hypex amps would it possible for amirm to also do this measurement when turning off the amp after it has reached a "normal" operating temperature (say 30deg C+) as the results could potentially be quite different. Mine seem to be as dependant on temperature as much as time.
For example, my four NC502MP modules behave quite differently depending on time and temperature. On power up (already on standby and using Octo Research DAC8 PRO as the preceeding equipment) there is no power up noise at all. If I power down to standby after about 7 minutes (from cold) there is a quite loud pop from the left channels, but nothing from the right channels. Conversely, after reaching 30deg C and then powering down there is no noise from the left channels at all and a quieter pop from the right channels.
As these modules are in one case I guess it is possible that there is some interaction between them at turn off. Each pair of modules have their own power cords and standby switches.