bought this to replace an aging Sony Home Theatre receiver connected to my PC. I've purchased cheap amp's to power passive speakers in the past but those all have a hiss sound when there's nothing playing. This unit does not have a hiss sound so long as it's connected to a source that it powered on. When the computer is off and this amp is turned on, you'll hear a hissing sound (which can easily be turned off). Works really well as a hook up to my PC and passive speakers. only wish the aux out had a stronger subwoofer output.