[Amps] Fan for SB220

[Thomas Carlsson]

Sorry, but I feel we are in for a misunderstanding here.
I have seen suggestions to paint inside, existing shielding black, to
minimize heat reflection and maximize heat absorbation.
Have nothing seen about funnelling the air. On the other hand, I have read
that the design is very elegant and cheap as it cools both the tubes and the
socket with its horizontal airsrteam. There are other clever solutions in
the SB220 to save money. Of course its brother Drake L4 was more robust, but
more $$!
We must let Amplifiers be a bit noisy to show their muscles, I would not
slow down the fan, but that's me.
Google: "Heathkit SB220" and you find a lot of info.
73,
Thomas, PY2ZXU/SM0CXU, member of the PW2D Contest Team.


On Fri, Dec 17, 2010 at 7:07 PM, Steve Thompson <g8gsq at f2s.com> wrote:

> It's not surprising that the sides facing each other should get
> hotter than the rest - but a metal screen won't help by shielding
> heat. If it's shiny it just reflects the heat back and if it's
> black it radiates the heat out as efficiently as it absorbs it -
> either way the effect is neutral. If it helps, I reckon it's
> because it acts as an air cooled heatsink, transferring some heat
> into the airstream.
>
> Steve
>
> > Bill:
> >
> > I think Don was mostly wondering about heat.
> > I had a Collins 20V2 broadcast rig that had a
> > pair of 4-400s that "talked to each other" in
> > terms of heat.   The two tubes weren't all that
> > far apart and the sides of the plates that faced
> > each other were more colorful than the "back
> > side" of the plates.
> >
> > But I agree with you about RF.   A non-issue.
> >
> > - JimT
> >
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-- 
Thomas, PY2ZXU/SM0CXU
Member of the PW2D Team