Hello All:

Look at this e-bay auction for high temp Chimney's. Pictured is a
3CX5000 Tube. Yeah I know only a driver, hehehehe

But I thought that the Chemney needed to have a .050 inch clearance
between the ID (inside diameter of the Chemney) and the OD (outside
diameter of the tubes plate. Allowing air to flow over the outside of
the tubes plate OD surface. Or is it ok to use such "Silicon Rubber
Chemneys" forcing all the cooling air thru the tubes inner plate cooling
fins?????

http://cgi.ebay.com/4CX5000-YC156-Si...cmd ZViewItem

I have seen these Chemneys on production model amplifiers.

Jay in the Mojave