Rough calculation shows 50 ohms ok for 833 up to 4 MHz but
marginal at 7MHz. It should be easily converted to grounded grid.
Bias already there.
73
Bill wa4lav
At 01:57 PM 3/2/2009 -0500, you wrote:
>It is a grounded cathode design, not G-G.
>3500VDC @ 300ma = 1 kilowatt input, 600W out. It would be a fun project.
>Looks like the Q was set to ±12.
>Bob W6TR
>----- Original Message -----
>From: "Bill Fuqua" <wlfuqu00@uky.edu>
>To: "AMPS" <amps@contesting.com>
>Sent: Monday, March 02, 2009 6:40 PM
>Subject: [Amps] Fwd: Re: 833A
>
>
> >
> >>Date: Mon, 02 Mar 2009 13:33:56 -0500
> >>To: Robert Perdue <kc0hfl@cox.net>
> >>From: Bill Fuqua <wlfuqu00@uky.edu>
> >>Subject: Re: [Amps] 833A
> >>
> >> I don't recall any grounded grid amplifier articles published using a
> >> 833.in grounded grid but it has similar amplification factor as a 250TH
> >> and I have run a pair of 250TH tubes in grounded grid as a teenager. That
> >> was before I was informed that you had to have higher Mu tubes for
> >> grounded grid. So, even though some will say it will not work, It will.
> >> You have to have a bias supply and the cathode impedance will be a bit
> >> high, which was no problem back then since I was driving it with a pair
> >> of 6146Bs via a pi network. The mu should be 35 or so and bias supply
> >> (depending on idle current and plate voltage) around -70 to -100 volts.
> >>73
> >>Bill wa4lav
> >>
> >>
> >>At 01:18 AM 3/2/2009 -0500, you wrote:
> >>>I acquired an 833A RF deck it is a 40/80M deck the only markings that may
> >>>refer to the design is P.J. 2000 on the front panel. Info is a little
> >>>scarce on this tube as far as rf amps go any ideas of what and when it
> >>>may have appeared in a handbook or a QST? I would like to at least try it
> >>>looks cool grounded grid thru a 55 ohm 100w resistor.
> >>>
> >>>
> >>>Bob,kc0hfl
> >>>_______________________________________________
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> >>>Amps@contesting.com
> >>>http://lists.contesting.com/mailman/listinfo/amps
> >
> > _______________________________________________
> > Amps mailing list
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