5150 feeback even when guitar is off!?

[theBlackLOBSTERmurder]

So I got a 5150 combo! FUCK YES BITCHES! (I think I might sell my fireball now )

...buuut, today I played it loud(5) for the first time and I got feedback when my guitar was OFF! how the fuck is this possible? I`m fuckin clueless, is this normal or what? and yes, I have a NS-2, but my guitar was fuckin OFF!

so I turned down the gain I bit to 5 and volume to 4, then no problem. but everything above that brings mean feedback. the amp is 12 years old, same preamp tubes, brand new power tubes (1 week). could it be the preamp tubes?

 

[Sloan]

A tube or tubes have probably gone microphonic.
Change them out and see if you still have a problem.

 

[devouredremains]

+1 to a microphonic tube.

 

[006]

Agreed.

~006

 

[JeffTD]

90% of problems with tube amps stem from the tubes!

Microphonic preamp tube. Replace all of those suckers - they probably need it, anyway!