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?
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I had solid state amps and sold them off. Wanted to get a tube amp a chance ,keeps blowing the power tubes . It does not sound like a tube problem but a amp problem. Thanks for all the responses.  
Whoever designed this amp the boss is running to high,
what brand  , integrated or power amp, and manual bias or auto bias ?
Here is solid advise , Buy a Ayon integrated amp why it it microprocessor controlled you bias it by holding in the button on back and each tube is run optimum ,and saves the tube life ,
when a tube does go ,it will shut off and let you know exactly which tube it is you wait 20 minutes , the amp rebias allthe tubes 
and ready to go , you shut off when not using very dependable .