Home amplifier

Question

I have a technical pro home amplifier i'm getting a humming noise from it? I have it connected to a surge protecter/filter and also have 30.5m high density speaker wire. And i still get the light hum from it! This amp is a intergrated power amp. It has a cooling fan on the back that pulls the heat out i'm wondering if that is were the noise is comeing from? The rated output power is channel A:1KHz.8? i dont know if the symbol after the 8 means ohms.And channel B is the same. would that be the problem if my speakers only have 4 ohms.