----- Original Message -----
From: "Roger" <sub1@rogerhalstead.com>
To: <amps@contesting.com>
Sent: Monday, August 30, 2010 1:54 PM
Subject: Re: [Amps] Tubes, made in the USA, in the olden days; Films?
>
>
> On 8/30/2010 12:02 PM, Rob Atkinson wrote:
>> I don't have the spec. sheet right in front of me but I recall the 833
>> could put out a hell of a lot of power with no forced air cooling.
>> 600 w.
> The 833A is a rather versatile tube with power output varying over a
> wide range. Forced air cooling increases the plate dissipation from 300
> to 400 watts.
>> (but I forget what biasing) sticks in my mind but don't hold me
>> to that. Whatever it was, it was very high and made me wonder why it
>> is not used in ham amps for all these operators who are obsessed with
>> not having any blower noise.
> Mainly to get much power out you do need to put about 40cfm out of a 2"
> outlet directed directly at the two top seals (plate and grid)
> In class C a pair of tubes can put out a lot of power (2400 to 2700
> watts with forced air cooling), but in class B it ain't much...(bout 225
> to 250 watts with 4KV on the plate with forced air cooling and only 150
> to 200 watts with convection cooling) But they are impressive and
> unique looking.
>
>
> If you want a convection cooled tube go with the GU81 which is As nearly
> odd looking as the 833. It's over 10" tall and nearly 5" in diameter. It
> *apparently* can be really abused. The Russians say the only way you
> can hurt it is with a hammer. There's a schematic on the net for a pair
> of them that claims 3KW out for contesting and no fan. I would assume
> the mechanical construction gives each tube a lot of space.<:-))
> Filament is Carbonized Thoriated Tungsten with 12.6V @ 11A
>
> BTW they reputedly put out a good signal and they are cheap!! Sockets
> run more than the tube at roughly $50 Vs $35
>
> 73
>
> Roger (K8RI)
Thats Class B AM Linear Roger and per tube. A SB-220 can barely run 250W out
that way in old buzzard style AM.
Carl
KM1H
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