I own a fender twin reverb tube amp and lately its been acting up. Every time I turn on my amp to play it gives me a semi loud static buzz. I'm not sure what's wrong. So you think maybe a tube is blown or is there anything I can do to test things to see if they work? Please help! Also if I were to take this into guitar center would they check it out for free it do that charge for that? Any help is very appreciated. Thank you guys for all the help you always are willing to give!
Sounds like a loose solder joint or dirty pot or input jack. if your not confident with repairs, take it to a reputable shop. No GC that Ive been to has repair shops, they generally do setups and thats about it.
Ibanez AF75
Takamine EG550
Digitech gnx3
Peavey Classic 50
Of the things you listed is there any tests or cleaning or tightening I can do fix them?
Does the buzz/static go up and down in volume with the amp volume knob?

The guitar volume knob?

Does it change at all when you plug a guitar cord into the input?

Both channels or just one?
It does go up and down with the amp volume knob I believe but not with the guitar volume knob. I can test that tomorrow for a sure answer but I'm pretty positive on that. And it has static on both channels! Also when I switch the "bright" switch on the static gets louder
That could actually be something as simple as an interference from something else in the room. I always get tons of buzz if i have a light with a dimmer switch turned on in the room. In fact, i had to get a pub to turn off some lights the last time I gigged because the buzz they were causing through my amp was louder than the guitar
MIA Fender Strat
Yamaha FG-450S
Crafter 12 string
Orange Rocker 30 combo
Vox AC30CC2
Epi Valve Junior
Fulltone Clyde
Danelectro Free Speech
T.C. Electronic Vintage Dual Distortion
Boss MIJ GE-7 (c1987)
Boss TU2
MXR Phase 90
Artec delay
Before anyhting as drastic as swapping tubes, try changing up your power supply.

That is, plug it in a few different rooms and outlets, try getting it away from computers and flourescent lights especially, and off the circuits that power them.

I've run into interference from other appliances, too, like the furnace and the fridge, although that tends to be intermittent (obviously...).

If there's still no change, check that all tubes are seated properly, this means pulling the covers off the preamp tubes and giving them a wiggle, or pull them and re-insert.

Same with power tubes.
The thing though is, is I play right next to a fender deville everytime and I'm plugged into thr same outlet as he is, yet there is no buzzing for him. I tried changing the power supply to a different extention but had the same problem. Also the only other things I believe plugged in to the plugs we use would be all sound equpment stuff. I've used to have this happen only once in a while but it happened all day yesterday which was odd. Ill try out take off the covers and unplugging and re inserting all the tubes tomorrow. I keep this amp at the church I play at and work all tonight, which is why I'm unable tp try and fix the problem untill tomorrow. Are there any more suggestions/ideas? Thanks so much for all the feedback already!
Solved! After some experimenting I found out it was simply a bad cord! Thanks for all the replies!
Ok bad news. Now when I play there's likes a buzz that is affected by two things. Not only where my guitar is in distance to my amp but also how its tilted. And the buzz gets louder and quieter with my guitar volume but even when guitar volume is down there is still a little buzz from the amp. I guess I was only five feet away when I played but I went all the way around the amp. Some places it would stop and some it would grow louder. There's also a few places I could be close with no buzz but I had to how the guitar forward and now really move. In using two brand new cables. Any ideas? Thanks yall.
how loud are you turning the amp up?
Gear :

Gibson Les Paul Special
Fender Koa Stratocaster
Korg Pitchblack
Dunlop 535Q Crybaby Wah
BBE Boosta Grande
Fulltone OCD v4
EHX Russian Big Muff Pi
Vox Night Train
Egnater Rebel 112x Cab
Marshall Class 5
I have it at 2 1/2 but also when I turn up the volume on the amp it gets louder too!