[Amps] Tubes, made in the USA, in the olden days; Films?

[Patrick Barthelow]

The 833s I saw years ago in their transmitter cabinets, at an AM broadcast station had no chimneys or ducts to cool them just a lot of 
general blower air around them.  The mounts were also very simple....two huge Filament pins on the bottom,  and two large pins one Plate, and the other grid on the top of the tube.  Would be easy to mount for a ham amp but the problem is a huge plate capacitance, which limits their upper practical limit in ham service to maybe 40 meters as I recall.  They would be a cheap killer solution to a 
160 amp.   Probably had as pulls for cheap from AM broadcast stations that used to us them.

Best Regards,   
73, de Pat Barthelow AA6EG 
 
> Date: Mon, 30 Aug 2010 11:10:58 -0500
> From: mikea at mikea.ath.cx
> To: amps at contesting.com
> Subject: Re: [Amps] Tubes, made in the USA, in the olden days; Films?
> 
> On Mon, Aug 30, 2010 at 11:02:21AM -0500, 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. (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. My guess was supply, cost of the tube,
> > and the (for hams) unconventional way they are mounted.
> 
> Add that they're not good in linear service (think Class-C), as I
> understand it. They _are_ most interesting in appearance. 
> 
> -- 
> Mike Andrews, W5EGO
> mikea at mikea.ath.cx
> Tired old sysadmin 
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