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

Thx lowrider.  Amp is SS and hums only thru transformer. Hum goes up in volume and then down in a cyclical type pattern.  

I had that problem once when I lived in a place with very poor power. It was DC getting into the line. I ended up just unplugging stuff when it happened and returning a hour or so later. It was annoying and aggravating. I tried gear to block it unsuccessfully. I was running a tube amp at the time.

I think it's dc getting into my line too. Very frustrating. 

My problem was hum with dryer/dishwasher/blow dryer/fluorescent lights/dimmer switches being used, and that's with a dedicated line to the listening room. The above posters have already given you all the information you need. Hope you get it resolved soon.

Tom

Thx Tom!