Hi Jerome,
I had to smile to myself when I read the very last line of your note
(below), i.e. the fact that you'd built the amplifier some 50 years ago...
It reminded me a lot of the old story of the 95 year old man, who, while
visiting his family doctor for his annual check-up, was told by the
attending medicene man to quit his daily habit of smoking cigars and
drinking brandy, as the two would ultimately kill him...! Hi Hi.
If it's worked lo these many years, then why worry about changing things
now...?!
~73~ Eddy VE3CUI - VE3XZ
********************************
----- Original Message -----
From: "jerome schatten" <romers@shaw.ca>
To: "Carl" <km1h@jeremy.mv.com>; <jtml@vla.com>; <amps@contesting.com>
Sent: Monday, September 07, 2009 12:13 PM
Subject: Re: [Amps] 304TH, 304TL, 813
> 1. How to tell if the 813 has graphite or tantalum plates? I have one
> pair from the early '40's and one pair made in the early 60's; I
> rotate them every year or so.
>
> 2. Amp runs only on 80/40/30m at 2200v, grids strapped to chassis;
> zero bias; no suppressors. The pi output circuit uses a very robust
> variable inductor (square copper wire) that progressively shorts out
> un-needed turns. Does it make any difference which end (plate or load)
> the shorting of the turns takes place?
>
> 3. Fan sucks the hot air out from the top right above the tubes;
> should I be blowing air in instead?
>
> All these things I never thought about when I built it almost 50 years
> ago.
>
> jerome - va7vv
>
>
>
>
> On Mon, 07 Sep 2009 08:24:38 -0700, Carl <km1h@jeremy.mv.com> wrote:
>
> > There are some running 813's at over 3kv daily on AM; I didnt ask if
> > it is
> > graphite or tantalum plates. I run close to that with graphite
> > plates and
> > never a hiccup.
> >
> > IMO, the 813 is a highly underated tube and Pd with a bit of air is
> > easily
> > 250W.
> >
> [...]
> _______________________________________________
> Amps mailing list
> Amps@contesting.com
> http://lists.contesting.com/mailman/listinfo/amps
>
_______________________________________________
Amps mailing list
Amps@contesting.com
http://lists.contesting.com/mailman/listinfo/amps
|