Raybo76,
Assuming the hum you are hearing from the speakers is due to a ground loop you need to start from each amp and build out to the source/s.
Start with only one amp connected to the preamp. (Unplug all other ics from the preamp's inputs as well as outputs.
Unplug all other associated equipment from the AC power outlets.) Isolate everything else from these two pieces of AC powered equipment.
If no hum...
Connect the second amp to the preamp. Check for hum.
If no hum...
Connect one front end source to the preamp. Check for hum.
