[AMRadio] 813 question

[Brett gazdzinski]

I have about ten 813 tubes, mostly hamfest specials, actually,
they are ALL ham fest specials.

When I built the 813 rig, I picked 2 and plugged them in, been using 
those same tubes for 15 years.
At one point, I went through my collection, plugging in one tube 
at a time, and they all worked well.

I think there are 2 different kinds, ones with graphite plates, and a few
with metal plates?


Over all the years of using tubes, I had one 75th loose its filament, and
one 4d32 has a piece of metal floating around in it (but it works), and
I have an 811 with no plate cap. The 75th was the only one that ever failed,
although I have got some bad tubes at fests (4-400, 4cx250b).

The Russian 811 tubes all have loose bases and I don't use them.

Brett



 

> -----Original Message-----
> From: amradio-bounces at mailman.qth.net 
> [mailto:amradio-bounces at mailman.qth.net] On Behalf Of ronnie.hull
> Sent: Tuesday, January 31, 2006 1:17 PM
> To: Discussion of AM Radio
> Subject: Re: [AMRadio] 813 question
> 
> 
> I have certainly never heard of that, but I'm no expert. 
> However, I have a box
> full of 813's that are ww2 vintage and NONE of them have loose bases.
> 
> R
> 
> 
> ---------- Original Message -----------
> From: charles free <mjcal77 at yahoo.com>
> To: amradio at mailman.qth.net
> Sent: Tue, 31 Jan 2006 07:12:56 -0800 (PST)
> Subject: [AMRadio] 813 question
> 
> > Hello all,
> > 
> > I have a buddy who insists that if I don't get my old
> > 813's out of the "future project" box and fire the
> > filaments up on them now and then, the base seals will
> > eventually deteriorate.  I guess he is talking about
> > the adhesive that secures the base to the bulb.  I
> > don't see how the glass envelope where the leads pass
> > through the glass could be affected by lack of use,
> > but maybe one of you folks has experience with this. 
> > Anybody heard of this one before?
> > 
> > W4MEC, Charlie in NC
> > 
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> ------- End of Original Message -------
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