I have one of these as well. It's a nice mic. I haven't had issues with mine at this point, but I recall having a similar problem years and years ago with an old Groove Tubes GT6 (Sterling is Guitar Center branded Groove Tubes mics). I ended up replacing the tube and it was good to go. If you need to replace your tube and can't find a replacement, drop me a line. I [i]MIGHT[/i] have an extra. I will have to check my stash.