I doubt it's clipping since it happens on moderate volumes as well.

If I power up the 970 first, there is no popping. But this is my second 970 (returned first), and never had popping when my amp was on before the 970, with my first 970.

There seems to be an incosistancy with the quality of the units Outlaw is selling. I've noticed different issues between my two 970's.