[Amps] cooling chimney?

[Russ Williams]

Pat, I have an L-4B inline and have another on the bench for repairs.  Both amps have straight-sided chimneys (ies); the glass is a bit thicker than the Coleman, and they are shorter than the coleman--FWIW.

73.
Russ
W6OHM  



--- On Mon, 7/14/08, Pat Barthelow <aa6eg at hotmail.com> wrote:

> From: Pat Barthelow <aa6eg at hotmail.com>
> Subject: Re: [Amps] cooling chimney?
> To: amps at contesting.com
> Date: Monday, July 14, 2008, 1:37 PM
> Regarding the cooling of the plate cap,  Eimac in their
> Applications notes show how, even though the Coleman
> Pyrex cylinders have no curve, that the air, as it
> encounters the top of the tube,  curves anyway, and becomes
> a little turbulent, which I think is a good thing, as it
> encounters the glass curve leading to the plate cooler.  As
> I recall, the Drake L-4B  with 3-500Zs uses straight sided
> glass chimneys.  Their Plate Cooler, is distinctively
> different than the classic horizontal fins.  But the L-4 B
> is a well respected early amp design.  I have one, but it
> is in storage right now, so I cant double check to see if
> the chimneys are straight sided.   The 3-500Zs in it have
> had heavy use, for its whole life, and are the originals 
> are still installed with a 1968 Date Code.
> The other excellent robust enhancement for cooling, is a
> Muffin Cooling fan sucking air from the outside of the
> cabinet just above the tubes.
> 
> Best, 
> Pat, AA6EG
> 
> > From: bmaser at tampabay.rr.com
> > To: km1h at jeremy.mv.com; hrd998cc at yahoo.com;
> kc0nxm at sbcglobal.net; amps at contesting.com
> > Date: Mon, 14 Jul 2008 16:22:03 -0400
> > Subject: Re: [Amps] cooling chimney?
> > 
> > I have always been told that the most important
> characteristic of cooling 
> > glass tubes is that you have to cool the part of the
> plate cap where it 
> > enters the top of the glass envelope.  Overheating at
> that place can cause 
> > catastrophic failure.  I would be wary about using a
> Coleman lantern globe 
> > because of this.  Besides, why not just go out and buy
> the correct chimney 
> > that has been designed for the tube.  You wouldn't
> put recaps on a Porsche 
> > Carrera.
> > 
> > Bob W6TR
> > ----- Original Message ----- 
> > From: "Carl" <km1h at jeremy.mv.com>
> > To: <hrd998cc at yahoo.com>; "Stirling
> Schmidt" <kc0nxm at sbcglobal.net>; "AMPS 
> > submit" <amps at contesting.com>
> > Sent: Monday, July 14, 2008 4:04 PM
> > Subject: Re: [Amps] cooling chimney?
> > 
> > 
> > > This goes back to the 60's so I have no idea
> what is relevant today nor 
> > > what
> > > country those parts are made in now.
> > >
> > > Id suggest doing a Google and see whats current
> in discussions.
> > >
> > > And a call to Eimac should also generate an
> answer.
> > >
> > > Carl
> > > KM1H
> > >
> > >
> > > ----- Original Message ----- 
> > > From: "Russ Williams"
> <hrd998cc at yahoo.com>
> > > To: "Stirling Schmidt"
> <kc0nxm at sbcglobal.net>; "AMPS submit"
> > > <amps at contesting.com>; "Carl"
> <km1h at jeremy.mv.com>
> > > Sent: Monday, July 14, 2008 3:25 PM
> > > Subject: Re: [Amps] cooling chimney?
> > >
> > >
> > >> Carl, can you elaborate on the problems using
> Coleman chimneys?  I plan 
> > >> on
> > >> using them for a 4-400a project and also know
> of 2 other hams using them
> > >> in conjunction with GS-35b's.  It seems
> the Pyrex/borosilicate glass 
> > >> would
> > >> be ideal for this application.  If there have
> been confirmed disasters
> > >> using them, other avenues may need to be
> pursued.
> > >>
> > >> I suppose a test in the microwave oven would
> illuminate any faults in the
> > >> Coleman's glass formula...
> > >>
> > >> Thanks.
> > >>
> > >> Russ W6OHM
> > >>
> > >>
> > >>
> > >>
> > >>
> > >>
> > >>
> > >
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> 
> > 
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