Just wanted to make a post so if anyone ever has the same or similiar issue, this may be a solution. I have an Egnater Renegade head, and switched it on for practice one night with the band when much to my surprise, this very loud crackling/buzz/popping noise came out.. Even with the master and channel volume on zero, the noise was horribly loud..
Fearing there was a short somewhere on the board, or possible a tube socket, I started to lightly rock the tubes, and unpluged/plugged in the input jack and effects loop jacks.. Sound now became intermittent, yet no solution to the problem. Had a tech listen to it via phone, and he said in his 40+ years of working on amps (mainly vintage) he hasnt quite heard a sound like that, but thought it was a loose connection on the board. He suggested I clean the jacks and tubes with contact cleaner. So, out comes my can of contact cleaner.. Sprayed all the pins (90 total), the tube sockets, and the input jack and effect loop jacks.. Long behold the problem disappeared and hasnt returned yet..
If your having some sort of problem with your amp in terms of noise, looks like a little dirt or crud can cause it.. Idk what exactly was dirty, but apparently the cleaner took care of it! Anyone else have a similiar expirence?