[font=trebuchet ms]Maybe.

How old is your amp? How old are the tubes? How hard do you use it? Tap them gently with a long pencil, or a plastic chopstick, to see if ony of them make crunchy noises.

It may just be old, dirty control pots. Do they crackle when you turn them?

It's also possible that the filter cap(s) in the power supply are dying. Time to see an amp tech.[/font]