Buzzing sound on an Orange Rockerverb 50 (HELP!)

[rickenbeatle]

I just got this amp yesterday and it sounds great, but a weird buzzing noise will come on for about 30 seconds or so, then go away. I am having trouble figuring out what it is because I don't know much about this stuff. I am running a pedal board into it. I tried plugging straight in to see if it was the board, and from what I can tell, you can't hear the buzzing that way. Although, with no noise suppressor, I hear your typical amp hum. So maybe the buzz is there but I can't hear it because of the hum. I tried just plugging my noise suppressor straight into the amp, still using the pedal board power, and the buzz was still there. It also appears that sometimes when I turn the knobs, it affects the buzzing. So is it something to do with the amp? Any help would be much appreciated. I spent too much money on this for it to have a problem.

Thanks!

 

[rickenbeatle]

i have determined that it is the amp. Any idea what it might be?

 

[RiftAmps]

One man's buzz is another man's hum....

Does it do it when nothing is plugged into the amp?
When you say that the knobs affect the buzzing, do you mean that the tone controls change the buzz or that the volume control makes it louder/quieter?