[Amps] Drake L-4B fan - too small and too slow?

[Peter Voelpel]

All the tubes of the 4/400 family (tetrodes) manufactured by Valvo,
Siemens, Telefunken etc. have graphite anodes.
Those anodes are already dark red at idle current and become
dull red or orange at their full dissipation starting from the bottom.
Most are specified for 350° glass envelope temperatur, 180° at
their socketpins and 220° at their anode pin.
The anode is specified with "dull red at 850° ".
The same applies to the triode family TBx/xxx and the BBC
zero bias triodes like T-510.
I use QB4/1100 (4-400A, RS1002A)  highµ connected in my L4Bs
for almost 30 years with the first set of tubes.
One is with the original P/S, the other with a homebrew delivering 4KV.
On the latter I use an EBM blower and also cool the bandswitch with
a small fan. The tubes anodes usually are red/orange on long transmissions
with 2K out ( 900W dissipation).
With the original P/S they are  red at 1300W out. and 700W of dissipation.

73
Peter



-----Ursprüngliche Nachricht----- 
Von: "Karl-Arne Markström" <sm0aom at telia.com>
An: "R.Measures" <r at somis.org>; "John" <crazytvjohn at yahoo.com>
Cc: <amps at contesting.com>
Gesendet: Samstag, 31. Dezember 2005 14:34
Betreff: Re: [Amps] Drake L-4B fan - too small and too slow?


> Some Amperex 3-500Z were manufactured with graphite anodes
> (European designation YD1130).
>
> In the Philips/Mullard databooks there was a general caution against
running
> tubes with graphite anodes so hard that they showed any color.
>
> 73/
>
> Karl-Arne
> SM0AOM
>
> ----- Original Message ----- 
> From: "R.Measures" <r at somis.org>
> To: "John" <crazytvjohn at yahoo.com>
> Cc: <amps at contesting.com>
> Sent: Saturday, December 31, 2005 2:11 PM
> Subject: Re: [Amps] Drake L-4B fan - too small and too slow?
>
>
> >
> > On Dec 30, 2005, at 6:16 PM, John wrote:
> >
> > > Hi Jason
> > >   My L4 used Amperex 3-500Z tubes.  When used at the power level in
> > > the drake manual and the Drake tune up procedure, did not show any
> > > color except at long key down at I kw input.  The manual said they are
> > > not to show color.
> >
> > Does Amperex know this?
> >
> > > The L4 was made for a short time before the L4B .  The L4 is much
> > > rarer.  The ability to see the tubes causes problems for the mind.
> > > Think of the poor tubes in the AL82.
> > >
> > >   john
> > >   kb9tc
> > >
> > >
> > >
> > >   Jason Buchanan <jsb at digistar.com> wrote:
> > >> I just sold my L4 and anything key down at or over 1kw input caused
> > >> the
> > >> plates to glow very orange.
> > >
> > > same here - 3-400Z idle on SSB mode causes them to get dull orangish.
> > > Sometimes I wish I had some of the new 3-500Z graphite jobs but the
> > > fan just
> > > isn't up to snuff to keep them alive.
> > >
> > >
> > > 73 Jason N1SU
> > >
> > > -- 
> > > Jason Buchanan - Boxboro, MA
> > > Website: http://n1su.com/
> > >
> > >
> > >
> > > _______________________________________________
> > > Amps mailing list
> > > Amps at contesting.com
> > > http://lists.contesting.com/mailman/listinfo/amps
> > >
> > >
> >
> > Richard L. Measures, AG6K, 805.386.3734.  www.somis.org
> >
> > _______________________________________________
> > Amps mailing list
> > Amps at contesting.com
> > http://lists.contesting.com/mailman/listinfo/amps
> >
> >
> > -- 
> > No virus found in this incoming message.
> > Checked by AVG Free Edition.
> > Version: 7.1.371 / Virus Database: 267.14.9/217 - Release Date:
2005-12-30
> >
> >
>
>
> -- 
> No virus found in this outgoing message.
> Checked by AVG Free Edition.
> Version: 7.1.371 / Virus Database: 267.14.9/217 - Release Date: 2005-12-30
>
> _______________________________________________
> Amps mailing list
> Amps at contesting.com
> http://lists.contesting.com/mailman/listinfo/amps