Hi Gary,
You probably already got the answer by looking at the
message from W4ZT. If not, the approach would be to cool
the 800A7's (or 8874's) by building a plenum underneath the
anode coolers. Air from the existing fan or replacement
fan/blower would be fed into the plenum and through the
anode coolers. This appears to be one fairly common
approach. Another approach is to mount the tube(s)
horizontally, base(s) toward the rear, and again blow air
through the anode coolers, etc.
73, Bob K6ZZ
----- Original Message Follows -----
From: "Gary Smith" <wa6fgi@sbcglobal.net>
To: "Bob Selbrede, K6ZZ" <k6zz@ccis.com>,
<amps@contesting.com>
Subject: Re: [Amps] MLA-2500 Power Supply Capacity
Date: Thu, 19 Jan 2006 10:23:47 -0800
> My question is how do you intend to cool the 800A7's?
> If my memory is correct, the air was driven through (over
> and around ) the cooling fins of the 8874's in the
> MLA-2500's. The 800A7's need the air to be driven up
> past the base(s) and then through the calling vanes from
> underneath the chassis. 73,
> Gary...wa6fgi
>
>
> ----- Original Message -----
> From: <k6zz@mail.ccis.com>
> To: <amps@contesting.com>
> Sent: Wednesday, January 18, 2006 6:33 PM
> Subject: [Amps] MLA-2500 Power Supply Capacity
>
>
> > Hi Folks,
> >
> > I could use some advice on the MLA-2500 power supply.
> > I'm planning to put a pair of 3CX800A7's in a tubeless
> > but otherwise very good condition MLA-2500. It seems
> > like a straightforward modification, but I am somewhat
> > concerned about comments I have seen regarding the
> > ability of the power supply to handle these tubes. What
> > is it about these particular tubes that would put an
> > extra strain on the power supply? If they aren't driven
> > any harder than the original 8875's or a pair of 8874's,
> > what difference would it make? I could use different
> > tubes but I happen to have a good pair of 3CX800A7's so
> > I'm inclined to move forward if the power supply can
> handle it. >
> > I have no desire to push the modified amplifier to power
> > levels beyond its capacity, but I would like to
> > comfortably run the amp at the legal limit if the power
> > supply and tank circuit can handle it.
> >
> > Have you done this particular modification before? Is
> > the power supply up to the task? If not, what can be
> > done to improve its shortcomings?
> >
> > 73, Bob K6ZZ
> >
> >
> > _______________________________________________
> > Amps mailing list
> > Amps@contesting.com
> > http://lists.contesting.com/mailman/listinfo/amps
> >
>
>
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