> Given the high temps a tube can run at,
> it's conceivable you could design a pump-less cooling system based on
> convection currents and steam.
That's the basis for the 1966 QST article entitled "The Stanley Steamer."
That amp used only convection currents as the condenser was positioned
horizontally and became a part of the top cabinet. The Alpha Seventy uses
convection + the assist from a whisper fan as the condenser is oriented
vertically and forms part of the rear panel.
Convection vapor cooling in small amps normally uses a vented system and as
such, H2O is exposed to the ambient air -- and hence my reference to the
Florida climate for those scratching their heads wondering why the Florida
climate would have any effect on H2O purity. I've not seen a completely
closed and *unvented* vapor-phase cooling system that uses a pump, but they
may exist in larger applications.
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