Power Amp transformer hum - intermittent and increases and decreases in a few seconds

A little more info please...
Hums every time the amp is on?
Hums no matter the time of day?
Hums ever since owning the amp?
Any changes to system/house electrical devices?

Tom

Hums every time the amp is on?  Yes
Hums no matter the time of day? Mostly in morning and sometimes at night. Very sporadic 
Hums ever since owning the amp? Yes
Any changes to system/house electrical devices? None since purchasing the amp. 

Hi John,
If it's mechanical hum, then yes, there are a number of DC eliminators which should work for you.

If you live in a single family home, it may help more to try to eliminate the problem via the process of elimination. Turn off all the other breakers in the house first and see if the problem goes away. 
Best,

E