The ADAs incorporate multiple protection functions. One or more of these functions may be getting activated. It may be getting activated due to an ADA fault or speaker cross-over or wiring.
I've had one of my 1000s temporarily disconnect one of my M5s. It did what it was supposed to because the M5 is such a greedy swine.
Two 1000s and a 1500 shut down and I had to power them on and off to recover after a power line sag. According to Andrew, they should have recovered on their own. I don't plan to pursue this further at this point.
