i am currently testing an Adcom GFS7400 to drive my mains and center. when i turn the power on my speakers pop, same when i turn them off. i have it plugged into a Monster HTS1000. is this normal, and it there anything i can do to prevent it. any impressions on Adcom amps??? this thing sounds great, brought out elements in music and movies i have never heard before. really kicked up the low end.