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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Tube life is unpredictable enough that its understandable to be told 4 months is the tubes. But only if its a time or two. In normal use, couple hours a day, tubes should last a few years. More use, higher volume, less tube life. To get it down to 4 months though would be running high levels pretty much all day. Guess you could do this if you have inefficient speakers and listen a lot. Not saying that's what it is, just filling you in on what to expect from a guy with a couple decades experience with tube amps. More likely its like the others said, they're biased too hot, and the service will fix it. 

You really should name the amp and age and details. Its never derogatory to say what actually happened with a component. It helps us all know what to expect. If its a quality product people will know and say wow that's unusual. If its not people will probably know that too and say yeah as expected and more people will know to avoid. In other words its helpful to know.  

Not to mention if the place you sent it knows there's like a hundred eyes on this you are more likely to get good service. So there really is no reason not to say, and every reason to fill us all in.
Not enough bias voltage on the output tubes. They are drawing too much current! Probably over 50 milliamps. Most power tubes run around 35 milliamps.
FIRST. Who makes the amp? Go from there. Certainly a problem.
Power valves look a little brighter than usual?

You only get so many "turn on", with a valve. The way it’s heated up has a lot to do with tube life too. The slower they come up the longer they last.

Roberjerman said, they have to be bias correctly. They aren’t..
They are bias to hot for sure (over 50 EL34s 4 months is a push)

Dynaco ST 70 come to mind, if the bias circuit hasn’t been upgraded, they will gobble up power valves...Fixed a few of those..25-30 years ago.. Mc 275, can have a small valve that will cause red plating also.. Ideas, ay..

Regards