I’m in the market for an amp to power 4 atmos speakers. I was looking around for a cheap used amp and came across a sherbourn pa 7-150. I don’t know much about them but found out more when I did some reading. So the price of the 7-150 is close to a new a500 with warranty. I like the power the 7-150 has to offer but worried if it ever breaks down, vs warranty and less power from the a500. Can anyone help me out here?