Hum in speakers

Are you using an integrated amp or an amp/pre-amp combo? If it is an amp/pre combo, try unplugging the pair of input cables from your pre-amp to the amp, (AFTER turning the amp off first)  and see if the hum stops. If it does, then the hum is coming through or from your pre-amp. If so, plug it back in, turn the amp on, and then un-plug one source at a time from your pre-amp, until you hear it stop. If it does not stop when everything is un-plugged from the pre-amps inputs, the hum is coming from the pre-amp. Let us know the results.

With the Amps just plugged into the speakers the hum is still there

Go to Home Depot and get a "cheater plug". Try to get one that has 2 spades, and no ground (long, round) connection. If they only have the grounded type, just cut off that round pin. Plug your cheater into the wall with the amp attached. If that doesn’t do it, try unplugging the cheater with your amp connected and reinserting it into the wall upside down. Post your results.  May the force be with you.

With the Amps just plugged into the speakers the hum is still there

Is the preamp disconnected or just turned off? If off disconnect the preamp at the amp end. Also is the hum coming out of both speakers? Does the hum occur all the time? Which amps do you have? Some amps are known to have a low level hum.