[Amps] Can I cool too much the tubes?

[Colin Lamb]

"So the caution should be - yes, air is good.  Very good.  But if you are heating the anode to a temp beyond it's specification, the degragation in 
the condition of the anode is going to be happening no matter how much air is blowing over the envelope."

It might be useful to consider a couple of different tubes.

First, consider the 811A.  If the tube element gets red for very long, you will have a hole in the plate.  You could blow lots of air over this tube and it will still be limited in plate dissipation.

Now, consider the 3-500Z tube.  It will run with lots of color.  Blowing lots of air around this tube is much more meaningful as the plate is not likely going to be the cause of failure.  

I consider the benefit or running lots of air simply means that your tube will be able to dissipate the rated capacity.  If you do not have lots of air, dissipation will be less than rated.

73,  Colin  K7FM