From: Stephen G. Stanton [SMTP:ulflyer-at-i-cafe-dot-net]
Sent: Saturday, February 28, 1998 11:18 AM
To: 'Tesla List'
Subject: Re: 833A
Does anybody out there have an extra 833A filament clamp (they don't really
use a socket due to the two heater pins at the base) they could part with?
I find they're getting hard to find at swapmeets.
> From: SBJohnston-at-aol-dot-com [SMTP:SBJohnston-at-aol-dot-com]
> Sent: Thursday, February 26, 1998 1:21 PM
> To: tesla-at-pupman-dot-com
> Subject: Re: 833A
> Greg wrote:
> >I lucked up on an 833A triode (for free!).
> >I have no experience with the big tube.
> By some standards, it is not a "big" tube <grin>: it's typically a 500
> tube in continuous (CCS) broadcast audio or RF service. I have always
> them and even built a custom transmitter around four of them. They
> run a nice orange-red color at full power.
> The original RCA 833 was a strong tube with a very heavy plate structure.
> The story goes that they just ran and ran and wouldn't fail, so of
> RCA had to redesign a replacement for them, the 833A, with a
> sheet metal plate that had a shorter life - repeat sales, you know! I
> that one of the Chinese tube companies is making the 833 to the original
> I looked in the RCA transmitting tube book and here are some detailed
> for your application:
> Filament: 10 volts ac or dc, 10 amps.
> Plate dissipation w/natural cooling: 350 watts
> Plate dissipation w/forced cooling: 450 watts
> Class C amp or oscillator RF service, intermittant-duty (ICAS), w/forced
> DC Plate voltage: 4000 vdc max.
> DC Plate current: 500 ma max.
> DC grid voltage: -500 vdc max.
> DC grid current: 100 ma max.
> Plate input: 2000 watts max.
> Plate dissipation: 450 watts max.
> >Is it OK to mount it horizontally?
> Yes - it says so in the book, but I have not seen them mounted that way
> any commercial application. And I just noticed a week ago that the ones
> had in the garage have suffered filament collapse from vibration while
> sitting on their sides <damn!>. I think would mount it vertically.
> If you'd like I can scan the RCA book pages for you and send it to you
> directly as an email attachment - let me know the graphic format you
> TIFF or GIF (or something else).
> Steve Johnston