There is a basic problem with using a blower which "sucks" the air from the
amplifier. At best, it can create a perfect vacuum which means that
atmospheric pressure pushes air through the amp with a differential pressure
of about 15psi across the amp. If a pressured cooling system is used, the
air flow through the amp is limited only by the size of the blower. 73, Dan,
N5AR
----- Original Message -----
From: "Mark Beckwith" <mark@concertart.com>
To: "ROBERT MARSTON" <rmarston@sbcglobal.net>
Cc: <amps@contesting.com>
Sent: Saturday, February 14, 2004 10:25 AM
Subject: Re: [Amps] tube cooling
> K1TA:
>
> >the critical points that need to be met when cooling a tube
> >is to keep both the plate and cathode-heater seals below
> >their maximum ratings.
>
> Thanks Bob. Another respondent stated that as long as you move the
> specified amount of air through in the way in which it is intended to flow
> it doesn't matter whether you're pushing or pulling the air.
>
> In a broad sense, the manufacturer intends the air to flow past the base,
so
> as long as all the air starts below the tube, goes through or past the
base
> and exits past the anode, you're doing it right, er, right?
>
> Let me ask my question another way. I have an Alpha 86 which is the
loudest
> thing in my shack. If I could figure out how to move the same amount of
air
> through the tubes but in a quieter way, I would do that, but I'm looking
at
> extracting the air out the top of the amp, as long as the airflow remains
> consistent with the way it works currently. I believe the chimneys/ducts
> inside there pretty much limit the air to going where it's supposed to.
>
> Does anyone have any thoughts on quieting an Alpha 86?
>
> Mark, N5OT
>
> ----- Original Message -----
> From: "ROBERT MARSTON" <rmarston@sbcglobal.net>
> To: "Mark Beckwith" <mark@concertart.com>
> Cc: <amps@contesting.com>
> Sent: Saturday, February 14, 2004 10:27 AM
> Subject: Re: [Amps] tube cooling
>
>
> Typically they are between 200 and 250 Degrees Celsius. Sucking air from
> the top of the anode in most cases does not provide sufficient airflow
over
> the cathode connections to keep them below their ratings. The water cooled
> variant of the 4CX10K requires 30 CFM to keep the cathode seals below
their
> rating. You can get around this problem directing a second source of
forced
> air at the base. For all of the extra trouble this entails it's more
> practcal to push the main source of cooling air up through the base in the
> first place.
> >
> > Adios
> >
> > Bob K1TA
> >
> > Mark Beckwith <mark@concertart.com> wrote:
> > Could you wise old sages help me with simple question - I seem to recall
> > hearing that forced air cooling was not the same as, shall we say,
sucked
> > air cooling. Do I remember right? Seems you could destroy your amp if
you
> > tried to suck the air through the tube(s) tops as opposed to pushing it
> > through from the bottoms.
> >
> > Advice please. Thanks in advance.
> >
> > Mark, N5OT
> >
> >
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> > http://lists.contesting.com/mailman/listinfo/amps
>
>
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