[Amps] Coupling a blower to an air system socket

[KA4INM]

On 03/15/13 16:58, Alan Ibbetson wrote:

> For minimum airflow resistance for a forced air cooled amplifier it
> would seem the blower needs to discharge in a straight line directly
> into the underside of the valve socket. This leads to a fairly tall
> structure with the blower underneath the RF deck.

> What is the "right" way to make the physical connection between blower
> and air system socket? Rigid ducting? Something resilient like rubber?
> Or (what intrigues me) how about a fabric transition duct as shown in
> several places here

> http://users.pipeline.com.au/~burst/stc.htm

> The "floppy" fabric seems attractive as a way to take up minor (major?)
> misalignment between the blower and RF deck if they are built as
> separate units and should help isolate any blower vibration. A competent
> seamstress (seam-master) would be able to take differences in duct shape
> and size in their stride too.

> Has anyone got a feel for the pros and cons of the use of fabric rather
> than more rigid blower couplings?

   I should think the difference is negligible and not worth the bother.
Many successful amplifiers using all kinds of air cooled tubes have been 
built with the system where they are simply pressurizing the box under 
the tube/s with the air passing through or around the tube/s above.
-- 
   Ron  KA4INM - Youvan's corollary:
                 Every action results in unwanted side effects.