[Amps] New Guy, Old 813 amp

[k7rdx]

I have done this both ways,thru a seperate choke and thru the cathode side
of the filament choke...Same results both ways...73,Jim..
----- Original Message ----- 
From: "Tom W8JI" <w8ji at w8ji.com>
To: "k7rdx" <k7rdx at charter.net>; <rbonner at qro.com>; "'Roger D Johnson'"
<n1rj at adelphia.net>; <amps at contesting.com>
Sent: Friday, April 27, 2007 10:05 AM
Subject: Re: [Amps] New Guy, Old 813 amp


> > in swr mode and watch the amp input as I operate...Very
> > stable. BTW,I knew
> > abt the filament hum problem Tom mentions....You can`t use
> > ct on the fil
> > trans for neg return with a tube that has one side of fil
> > and cathode
> > common..Found that out (& cured it)several years ago while
> > playing with a
>
> You also very often cannot pass the dc through the filament
> choke winding that carries filament current.
> It can cause hum even without a center tap connection simply
> because of the I*R drop of the copper.
>
> In my amps with the cathode tied to one side of the filament
> I use an entirely different choke for the cathode path. Not
> the bifilar choke the filament uses.
>
> 73 Tom
>
>
>
> _______________________________________________
> Amps mailing list
> Amps at contesting.com
> http://lists.contesting.com/mailman/listinfo/amps