On Fri, 6 Jun 97 09:46:09 -0700 Rich Measures <measures@vc.net> writes:
>>
>>On Thu, 5 Jun 97 15:08:50 -0700 Rich Measures <measures@vc.net>
>writes:
>>>>At 01:35 PM 6/5/97 -0700, you wrote:
>...snip...
>>While the SB-220 has sufficient air for Tantalum plate tubes, it is
>>marginal for Graphite. ...
>
>Why is a graphite anode cooler more adept at heating the glass than a
>metal anode cooler, Carl?.
>What is the diameter of the Harbach replacement fan blade?
The graphite tube conducts less heat away from the cooler and thru the
glass at any given instant Rich compared to Tantalum....correct me if I
am wrong. The Graphite retains the heat and very slowly releases it thru
the glass.
That is why I always recommend a 2-3 minute cool-down when Graphite tubes
are used; particularly in amps with a transverse air flow.
The Harbach fan runs at a higher RPM only; fan diameter, pitch, etc
remain the same. The increased air flow is very evident and can be
verified by the simple expedient of placing a piece of paper on top of
the tube cage. It dont take a PHd to feel it either.
73....Carl KM1H
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