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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