Start with process of elimination diagnostics.
Unplug everything (including interconnects as well as power cords) except the amp to the speakers. Do the speakers still hum? Is it one channel or both? If it hums with nothing else hooked up, then you probably need the amp looked at.
If there is no hum with the amp only, start adding components back one at a time. When the hum returns, try some other combinations of equipment to see if you can further isolate the source.
Try a different set of interconnects and power cords to see if you might have a bad cable. If you get to where it works, then you may have located either a defective cable or one that simply isn't suitable for your setup.
There are additional things you can try (floating grounds, using one power outlet or using two different ones, etc.) but the initial goal is to simply isolate the problem. Once you've found the hum source then you can start working on the solution.
Unplug everything (including interconnects as well as power cords) except the amp to the speakers. Do the speakers still hum? Is it one channel or both? If it hums with nothing else hooked up, then you probably need the amp looked at.
If there is no hum with the amp only, start adding components back one at a time. When the hum returns, try some other combinations of equipment to see if you can further isolate the source.
Try a different set of interconnects and power cords to see if you might have a bad cable. If you get to where it works, then you may have located either a defective cable or one that simply isn't suitable for your setup.
There are additional things you can try (floating grounds, using one power outlet or using two different ones, etc.) but the initial goal is to simply isolate the problem. Once you've found the hum source then you can start working on the solution.