Hi folks. I know this isn't bass related but I'm trying to help out a friend. He just acquired a fender deville today. He played it for 20 minutes, took a break, came back to it and the amp started making popping sounds with a little bit of crackling. I'm thinking that maybe its a bad solder joint or capacitor. Now if he turns the amp off and then back on, its fine until about 5 minutes in where it starts to pop again. The thing was returned recently retubed so perhaps this is a result of a poor job or a faulty tube? Needless to say its a bit of a bummer. Any insights?