On Sat, 09 Apr 2005 17:17:56 +0200, Patrick wrote:

Hi All,

I'm about to build a 4CX1500B amplifier for 2m.

snip
For several reasons i would like to blow into the anode enclosure directly
onto the anode, the air would then go out through the anode chimney.
snip

Not sure if this matters but on the larger tubes, the cool air was needed
to keep the tube contacts from heating. Also, there was an issue with heat
buildup on the base of the tube due to the filaments.

The tubes I am talking about were the 3cx15k and larger in a broadcast
environment so this could be moot.