Subway Blues buzzing

[burnt_rissole]

I just bought a second hand Mesa Subway Blues and it's a fantastic amp. The only thing is that when I turn the volume about halfway or more (where the fun is) there is a distinct glass sounding rattle. I've taken the tubes out and none of them seem to have that rattle of bunged tubes, and even when the amp is on and you lightly tap them there is no rattle.
I don't know how bad the rattle really is but it's one of those things that just bugs me when I'm playing. If anyone has any ideas please let me know.
Cheers

[Blue Strat]

Could be anything in the amp. Try connecting it to a seperate speaker cabinet and see if it goes away. If so, the problem could be a loose screw, bad speaker, loose component inside the chassis, etc.

[onemind]

My Subway Rocket needed a little foam around the baffle because it vibrated at louder volumes, try presseing on different parts of the cab while a note is ringing to see if that attenuates the noise.

[bluesmain]

Great little amp and I found the buzzing in mine was the foil wrap inside the head section.

[burnt_rissole]

Thanks, for those now i've had everyone i know have a listen it actually sounds like a loose screw or something of the sort. Dammit if it was just tubes it would be easy

[John Phillips]

I can't remember for certain but I think this model has a long screw which runs up through a captive nut in the chassis floor and presses on the inside of the cabinet under the handle (some other Mesa combos definitely do). I've never been totally certain whether the point of this screw is to provide better ground contact to the foil (it shouldn't need it though, because it does so on the chassis ends) or to help stop rattles - both the cabinet and the chassis of these cheaper Mesas are quite flexible and a bit prone to this. Make sure the screw is tight - but not too tight (stiff finger tight is enough actually), if you overdo it it bends the chassis down. If it's actually loose it will definitely rattle in the captive nut though.

If you're taking the chassis out, make sure you undo this screw first and tighten it up last when you put it back.