Sounds to me like what I just had on one of my amps....mainly loose tube sockets, and maybe a bit of oxidation.
The "springs" that hold/contact the pins can open up over time, and you get all that noise. If you *gently* rock the tubes with the amp on, and you hear lots of noises...that's the problem.
Cleaning with DeOxit stuff is step one, I like to use the Caig D100L, and just tab it on the tub pins with a Q-Tip, not real wet, just enough to leave a film, then work the tubes in/out of the socket a couple of times and then seat the tube all the way normally. The D100L cleans, but also helps with improving the connectivity....
....but you really need to re-tighten the springs to get all the noise out.
This guy shows it nicely how it's done. Not a hard thing to do....mind the instructions on draining the amp juice off before you start sticking things into the sockets, and if you use a screwdriver with an insulated handle, all the better...and of course, before starting, the AC plug.
I wouldn't bother with re-soldering the pin connections unless after tightening, you can still gently rock the tube and get lots of noise and movement of the entire pins. On fairly new amps, the solder joints should be fine, it's mostly the pin springs that open up.
In my case, I always find this type of problem with
the preamp/9-pin sockets. I've never had issues with the bigger power/rect tube sockets.
Also, you can stretch the springs inside the tube covers out a little more so that they push down on the tubes a bit harder, which will keep them more solid in the socket. Watch it, if you pull hard enough, the springs can come out of the sleeves...but no big deal, just push them back in. You don't need to stretch them a lot...just make them maybe a half to one centimeter longer than they were.
Billm Audio » Re-tension, re-solder your tube sockets