Review on Monoprice Unity 100W Bridgeable Power Amplifier in Black by Damon Mertz

I bought this amp to power my Denon X4300H Dolby Atmos rear ceiling speakers but returned it for two reasons. 1) I couldn't use a 12V trigger without the 60Hz hum due to the ground loop. This amp is grounded unlike most AVRs. Also, it doesn't use an opto-isolator on the 12V trigger 2) Even with the 12V trigger disconnected, I still hear an audible hiss from the speakers when it's on. I ended up finding a used Niles SI-275 that didn't have any of these issues. It's a shame, because otherwise the amplifier has good features and is compact.