My Fender Blues Junior NOS gets a slight tube rattle at certain frequencies. I've been told that replacing the tubes can solve this issue.

Does anyone know of some good quality tubes that I can purchase for replacement?
FYI, I notice the rattle only when the reverb is on. Is this because the reverb is making the tubes rattle, or do I have a issue with the reverb? I don't have access to a reverb pedal to test out...
I don't remember off the top of my head if the Blues Junior has spring reverb, but that could possibly be somewhat of a cause of rattle. My amp made the reverb springs rattle when I used to play it very loud.
my Blues Jr. has been doing that too, and it's been very annoying when playing/recording. I think that it's got something to do with the reverb tank but I'm not sure, could be a loose screw somewhere.
What would be the best way to find out what the problem is? It only happens at certain pitches when the reverb is being used. It's not so much a rattle, but a hum that stands out above the actual note that I'm playing on the guitar.

I've heard that it's either:

Loose Screw Rattle

Tube Rattle

Reverb Rattle

Maybe I should just write down under what settings it happens and take it to a local shop that is authorized by Fender.
FYI, when I Received the Amp, the little tube farthest to the right fell out when I turned it right side up. I'm thinking that it could have damaged the tube.

I've heard that Power Tubes get too hot to touch, but the Pre-Amp tubes can be touched. Which tubes are preamp and which are power? I'd like to touch them while the rattle is being made to see if it's a tube.
If it's only a problem when your reverb is on then it's not a tube. That amps reverb isn't tube driven. So it's either a problem with a solder joint inside the reverb circuit or you are just getting normal reverb rattle and hum. Some reverb unites will give major feedback too! There are a few things you can do to reduce reverb rattle. 1 is to try loosening the screws that mount the reverb to the cab. If your reverb isn't in a bag then put it in a bag. If it is in a bag then put a sponge in the bag over the top of the reverb pan. Basically, do everything you can think of to minimize the vibrations your reverb pan can pick up. Also, reverb pans have a frontwards and backwards in terms of putting them inside the amp. If it was put in backwards then the pan will pickup transformer hum and can cause extra rattle and feedback so taking the pan out and turning it around might help. If it just makes things worse you can always put it back in the right way.

Loose screw rattle is also likely but that should happen whether your reverb is running or not.
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Thanks for responding, Cordury:

You're probably right about it not being tube rattle. This weird overtone is even produced at low volume, but again, only when reverb is on.

I know nothing about the reverb system in the Blue Junior (or any other amp for that matter), and will likely have to do some research or bring it to a local guitar shop.

Thanks again!
I have a BJ Tweed NOS and it seems that the output tubes are really loose and causing intermittent connections and crackling noises. It can be heard when fairly cranked and holding a chord. (At first I thought it was a cable or pot) I notice it does it more on some chords and positions than others, due to the natural resonance of the cabinet and chassis.

Looking at the rear I can see one of the output tubes engaging and disengaging and when I wiggle it I can hear an improvement in the sound and fullness. Seems like a really poor design using two little springs in overly loose sockets to secure the output tubes, eh?

I have already had one tube almost go into meltdown, glowing a bright orange compared to the other tube. Installed a matched set of EL84's which seem to wiggle and sway with ease. I can visually see the "little blue flame" coming on and going out on one of the tubes when I move it around. Is this normal?
Any suggestions?