Fender Champion 600

Well, things don't always last as long as expected. Averages are just that, some last a lot longer and others much less. First thing to think about when a tube amp starts sounding not so good is whether a tube's going out. Best way to find that is by substitution, and it's a good idea to always have a full set of spares on hand, anyway. If you've been playing that much for that long, I really don't think you're entitled to fuss if a tube's gone bad. Usually the power tubes go out first, and the "preamp" tubes will last through several sets of power tubes. But again we're talking about averages, it's not always the case. And brand new tubes can and often do go out. There's a reason they plug into sockets.

BTW, with Class A amps, playing them at low volume isn't a bit easier on the tubes than playing them wide open. In fact, the output power is drawn from the power wasted heating the tube plate at idle, so the harder it's cranked, the cooler the tubes run!

(Not true with Class AB amps.)

There's a reason they plug into sockets.
:)

Thank you very much Ricochet. I'm an absolutely beginner to tube amps (and guitar too) and my doubt was if it was a normal situation, the solid state world is completely different. I guessed it could be more or less normal since you can found easily tubes in the guitar stores but the ignorance...

I understand we are speaking in average terms and 300 hours could be good. I'll buy a couple of sets of 12AX7 and 6V6. I have to do some numbers but perhaps it is interesting to use a second solid state amp just for rehearsal and leave the tube amp when you really need/want a tube sound.

Thank you very much again! :D

PS. Interesting the comment about the volume on the Class A amps.

I wouldn't say 300 hours is "good," but stuff happens. And of course it may not be a tube. But check it out, and like I said it's a good idea to have spares on hand. As far as tube failures (not gradual wearing out) go, they occur most often in the first 100 hours and tubes that make it through the initial burn-in period tend to be long term survivors. That's why I don't think it's a good idea to periodically swap out good, working tubes as "preventive maintenance." You may be increasing your chances of having one unexpectedly let you down. Ones that are in there working have been tested in service.

It does seem paradoxical that a Class A amp tube isn't stressed harder (in fact is heated less) when pushed to maximum volume. The tube electronics books explain it mathematically and graphically, but think of it this way: A tube operating under Class A has a constant average (not instantaneous) plate current and voltage, no matter the applied signal level. That means the power input to the tube is constant. At idle, with no sound coming out, that's all wasted as heat. If you're drawing out audio power, it's got to come out of that waste heat. Strange, but not really hard to understand.

Very interesting! It sounds reasonable. I'll read more things on tubes. I've found this paper (E. Barbour, "The cool of tube sounds," IEEE Spectrum, 1998). I guess you already know it although I don't know if it is available for everybody, my university has access to some IEEE magazines. It seems a classical paper. I didn't read it yet. If you don't have it, I'm glad to send to you.

I asked in the store and they told me they go to change the whole amp. It is covered by the warranty and their opinion is it could be another thing also, so not only the tubes.

That's a very good article by my friend Eric Barbour. He may be a bit eccentric about naming his high end boutique gear, but he most certainly knows his stuff!

If the amp's under warranty and they'll exchange it, go for it! Lots of things besides tubes can go wrong, of course.

I got the new amp yesterday after the work. I just played 10 minutes or so but it is much clearer than the old one. And I don't remember that clarity in the old. Even when I bought it, I think it made some buzz. Perhaps the tubes were wrong or there was another thing.

Their hypothesis was it isn't normal that duration. They sold a lot of gear everyday and nobody complain. Probably there is a problem with the board, the electronics or simply a bad welding. Furthermore, as the warranty covers it, they recommended the change.

Anyway, Ricochet, thank you very much for your support! :D

Glad you got that straightened out!