New to tubes.

I own an ASL MGSI15DT that I bought on Audiogon a few months ago.I've noticed that the last few times I turned the amp on,one of the 12ax7 tubes flares up inside
the bottom of the tube.I'm not sure of the age of the tubes.Is this an indication that they are starting to go,
or could this flareup be a sign of an internal problem?
If it looks like a flash upon startup this is normal with some European tubes.
This is fairly normal. All of my Yugo's do this as well as some others. Don't sweat it.
I'm using some old Seimen Falcon tubes that do the same thing and I ask the same question. I haven't had any problems and I too was told that this is normal with some tubes.
I had the same problem with the Svetlana 6550. I think this is normal.
I have this amp also, and I recently lost a 12ax7--fortunately, they aren't that expensive. You always should have some spares around, so if you hear a funny sound (some fuzz from one channel), you can just pop a new tube in and see if that's it. It almost always is.

If it's an internal problem, you probably won't get any sound at all--or you will get a lot of hum.

Another thing to have around is some spare fuses. I think that this one uses a 3 amp slo-blow. A few pennies at Radio Shack.

BTW, what speakers are you running?
I'd like to thank all those who took the time to respond
to my question.