>
>>Maybe amps with radiation cooled glass tubes and modest air flow
>requirements
>>have advantages if you live at high altitude, although it's not something
>that
>>I've ever had to consider.
>
>I keep hoping that someone will resurrect the vapor-phase method of cooling
>and incorporate it into commercial amplifier. Despite perceptions, the
>method is nearly maintenance-free and provided that all plumbing connections
>are secure, there's little danger of leakage. I presently use an original
>ALPHA SEVENTY that will one day require a new tube. However, its 3CV1500A7
>is scarcer than a Deforest spherical audion and I cannot find anyone with
>the necessary spirit, skill-set and tools to retrofit a boiler "dud" onto a
>new 3CX1000A7. Perhaps George Daughters will have some input. By the way
>George, nice article of yours in the March, 1966 issue of QST on "The Field
>Day Gallon."
>
>Vapor-phase cooling offers approximately ten times the plate dissipation
>efficency as that provided by forced-air cooling: power dissipation of
>approximately 500-watts per square centimeter of internal anode area easily
>achieved. Compare this with 50-watts per square centimeter using forced-air
>cooling and 100-watts provided by pure water cooling. I recently ran across
>an Eimac ad in that same year which featured the original "Stanley Steamer"
>by Jack Quinn, W6MJG. However, the ad introduced a tetrode version that I
>do not believe ever went into production. Its designation was the 4CV1500B.
>
? The fly in the proverbial ointment with vapor-phase cooling is that
the boiler is vented to the atmosphere. Thus, when the heat source is
turned off, air is sucked into the system. Human beings exhale carbon
dioxide gas. This forms carbonic acid when it contacts water. Carbonic
acid is a conductor of electricity. Carbonic acid also attacks the
metals in the boiler. In order to solve these problems, the coolant
would have to be protected from contact with the atmosphere. // Murphy
was right, everything Is more complicated than it looks.
- cheers
>Unlike the ALPHA SEVENTY, Jack's amplifier uses a horizontally-mounted
>condenser located atop the amplifier, negating the requirement of a small
>whisper fan but it also required a seperate water reservoir. ETO's version
>incorporated the reservoir into the bottom of a vertically-mounted
>condenser, much like an automobile radiator. All heat generated from plate
>dissipation is transfered by steam into the condenser where it converts back
>into cooled water and recirculates. Both amplifers run absolutely silent,
>little heat builds-up within the cabinet, and altitude is not factor. A
>much better description of the overall cooling process is decribed by Jack
>in the May, 1966 issue of QST.
>
>-Paul, W9AC
- Rich..., 805.386.3734, www.vcnet.com/measures.
end
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