Power Amp


My power amp keeps burning up the power tubes.  I get maybe 4 months out of them  . I have use three different type of tubes that are recommended for the amp. Can anyone help, why this is happening, are all of the power tubes bad?
128x128mcallij1
Oh boy...another "Don't want to name the brand" post.


^^^^
Yeah must be a  popular/highly regarded/highly respected  lab,,which must be protected from any bad press. 


I once had a hunch; I got rid of it and got a clue instead. Lucky I didn't go the other way. Then I wouldn't have a clue.