The idea in "star-grounding" is to leave the component with the highest voltage potential -- the amp -- grounded, and to unground everything (everything) connected to it.
BUT, if you want to determine if the hum is intrinsic to the amp, just disconnect all inputs, so that the integrated has ONLY the speakers still connected. If there's hum through the speakers when you turn the unit on, then you'll know that the problem is not due to a ground loop. If there's no hum, then you may want to try star-grounding.
BUT, if you want to determine if the hum is intrinsic to the amp, just disconnect all inputs, so that the integrated has ONLY the speakers still connected. If there's hum through the speakers when you turn the unit on, then you'll know that the problem is not due to a ground loop. If there's no hum, then you may want to try star-grounding.