New to tubes.

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.