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
|