>
>Years ago I had an SB220 and I was impressed with the quiet fan, pushing air
>transversly around the 3-500s.
>But I did have one filament pin unsolder, possibly a manufacturing defect
>but likely to be due to excess heat.
? Did you oil the fan motor bearings periodically?
>I gather SB220 have a reputation for good tube life, altho the available
>voltage means tubes are slightly under run.
>Seems to me that somone with a modest knowledge of the physics involved
>would be able to calculate the transverse airflow required to keep a 4-1000
>happy.
>I also suspect the a couple of copper fins added to the filament sockets
>might keep them happy with transverse flow.
>The standard plate connectors typically have transverse fins, so all in all
>the big fan seems quite a good way to go, if the numbers look good.
>Anybody out there able to do the calculation?
? I would measure the temperature on various parts of the tube with an
IR thermometer.
> ...
cheers, Barry
- Rich..., 805.386.3734, www.vcnet.com/measures.
end
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