Rickresource Rickenbacker Forum

My 1967 Fender Bassman 50 is in the shop for replacement of electrolytic and bypass caps. The tech still reports that the overall noise level has improved although their is still some static in the background noise. Any ideas what this could be?

Could even be old power tubes or tubes that are not biased correctly although I would think that the tech would have checked those two things already. These two things usually don't start until it's been on for at least ten minutes sometimes longer.

Worth considering. Thanks Bob.

First thing to check would be tubes. Second thing would be a bad ground somewhere or a loose connection. Third thing would be a bad coupling cap letting DC pass on to a following stage. If the static is intermittant, I'd suspect a loose connection or a bad tube. You may have him retension all the tube sockets to make sure you have a good connection there.

Even bad resistors will sometimes crackle and hiss when they are going.

Yep, that too, though in my experience, a bad resistor makes more of a crackle noise rather than a static noise. I guess it would help if you qualified what type of noise it is and when it occurs Peter. Usually, a bad crackling resistor is one of the plate resistors for the preamp tubes.