It was the cable going to and from the reverb tank. After swapping tubes and having the hum problem, I began tapping and found that tapping and moving the reverb tank resulted in the hum/no hum. I found the 4 tab connector loose. I went to Radio Shack and bought a better connector.
So, when you get the reverb tank you can check that as well. My tank sounds even better now than it did before.
You found your issue but this is a common issue for another reason .... A lot of folks think this is tubes since it comes and goes but in most cases it is the ground on your wall and noise comes and goes on the common ground.
Try a ground lift .... one of those two prong adaptors on the reverb unit .... I bet you find the problem goes away.
Maddog: Carl Spackler: Licensed to kill gophers by the government of the United Nations. A man, free to kill gophers at will. To kill, you must know your enemy, and in this case my enemy is a varmint. And a varmint will never quit - ever.
Apr 6, 2016 19:28:14 GMT -7
Maddog: They're like the Viet Cong - Varmint Cong. So you have to fall back on superior intelligence and superior firepower. And that's all she wrote.
Apr 6, 2016 19:28:56 GMT -7
poodle: Is that a turd floating in the pool or a Baby Ruth?
Apr 6, 2016 20:05:00 GMT -7
BritInvasion: I'm dealing with nothing but chimpanzees at work today.....
Apr 12, 2016 10:29:14 GMT -7
TeeDawg: Caddy Shack.......an all time favorite. How bout National Lampoon's Christmas Vacation.....
Apr 13, 2016 4:57:02 GMT -7
TeeDawg: It jest ain't Christmas till I've watched Vacation
Apr 13, 2016 4:57:21 GMT -7
Maddog: Eddie: You surprised to see us, Clark? ...........Clark: Oh, Eddie... If I woke up tomorrow with my head sewn to the carpet, I wouldn't be more surprised than I am now.
Apr 13, 2016 15:16:46 GMT -7
Maddog: Ed McDonnough: "You mean you busted out of jail."...Evelle: "No, ma'am. We released ourselves on our own recognizance"........Gale: "What Evelle here is trying to say is that we felt that the institution no longer had anything to offer us."
Apr 15, 2016 20:30:10 GMT -7