Humming noise in speakers

Each time I turn my system on, I get that humming noise in my Monitor Audio monitors. Why's that? How can I resolve this problem?
PARASOUND power amp/CONSONANCE CDP (directly hooked-up to the P.A.)/Audio Magic Stealth/Phoenix Gold IC's and speaker cables.
Thank you so much for your eventual help.
If it is an "electrical" hum the problem most likely is a ground loop. Try getting one of those three prong to two prong adapters (often called cheater plugs) from the hardware store. Plug your preamp power cord into it and then into your power source. What we are doing here is "floating" the ground on that piece of equipment in an attempt to reduce or better yet, eliminate the ground loop causing the hum eminating from your loudspeakers. If this doesn't work try floating another component and so forth until the hum stops.

Good luck.
I agree with the adaptor. You can also try to reverse the adaptor. Just turn it 180degrees in the plug. Honestly though, once I got a decent line conditioner, I have never had this problems since.

Which conditioner solved the ground loop problem? I don't have a conditioner yet but run into the occasional loop gremlin.

I had that and it was the refrigerater. If the ground thing above doesn't work, you could try to find the guilty appliance. I got a power line conditioner, Not only did the hum go away, but I spent about 3 times as much as it would to just make the hum go away because of the improvment in sound. And the inconsequential side effect of food that lasted longer.
It's better to float the ground on your power amp and
leave the preamp/source components grounded.

Also, check and sure your IC cable connectors fit tight.