Popping and Crackling noise Intermitting

I just got my MusicMan 210-HD 130 from the East Coast where I lived ...to California (like it matters...LOL) and the volume keeps going up and down and am getting a popping noise as it does... its like a volume pot is turned suddenly up or down... I turned the pots and dont see any change after it happens...love this amp on volume 3 or more... Tried the output tubes, no help, could it be the phaser tube? thanks
Oh, it was also happenning back east...

I left the amp on a hour or two and the popping went away as did the volume flucs...210-HD 130
here is a sloppy recording of the amp...who needs a amp modleler?..http://jimsi.royal.com/musicman.mp3

oooops...the right link test toneshttp://jimsi.royal-tt.com/musicman.mp3

Popping and changes in volume can be anything from a tube to a cracked resistor to a leaky or noisy capacitor.
There isn't one answer. The fact that it goes away after several hours of heating suggests that it may be a resistor or capacitor that is at fault.
Once the problem disappears, can you make any of the symptoms reappear by vibrating or shocking the amp (lift a bottom corner an inch off the floor and drop it to create a physical shock)?
Steve

Steve, I had the amp shipped from the East to the West coast, as it was sitting for 2-3 years... The volume flux has goes away and has not re-appeared since i have been using it, i cant re-produce it unless i let it sit for a while...I may take it apart and do a visual on all the solder joints and resistors caps componets...and clean the pots to boot...thanks