[Amps] 833A GG

Mon Jan 26 16:10:57 EST 2015

  I should do something with my 2000T. Hi Hi
73
Bill wa4lav

________________________________________
From: Carl [km1h at jeremy.qozzy.com]
Sent: Monday, January 26, 2015 2:59 PM
To: Fuqua, Bill L; Hsu; Mike Waters
Cc: amps at contesting.com
Subject: Re: [Amps] 833A GG

Heck I had a pair of 100TH's on 6M in the early 60's but no matter what I
did with the bias or drive could I get high output and no splatter at the
same time. At 3KV they glowed nice. Shortly after that National sold me a
NCL-2000 prototype for $20 (standard employee price for a lot of no
production items) which I converted to 6 and still use.

I believe the Orr amp was a 304TH. I built one for G&G  but looking at the
output with the 60's era spectrum analyzer at National I decided Id likely
get lynched if I put it on the air.

Never used a 833 at RF, just audio once to a 4-1000A in the 70's. These days
the AM guys still salivate over them and lots of 1KW BCB rigs converted to
160/75 use a pair at RF and audio.

Back in the early 60's Sam Harris, W1FZJ/W1BU, used a S Line and 30L1 to
drive a pair of 750TL's on 75 to a Lazy aimed at EU and VK/ZL.
I never saw the power output but the PS was 7500V and the tubes glowed white
on voice peaks. Signal reports of 20-30 over to VK/ZL were common

Carl
KM1H

--------------------------------------------------
From: "Fuqua, Bill L" <wlfuqu00 at uky.edu>
Sent: Monday, January 26, 2015 10:46 AM
To: "Hsu" <hsu4qro at gmail.com>; "Mike Waters" <mikewate at gmail.com>
Cc: <amps at contesting.com>
Subject: Re: [Amps] 833A GG

>  You know, I ran a pair of 250THs grounded grid back in the 60's driven by
> a pair of 6146Bs at 1kW plate input power.
> That was before I knew that you could not do it. I wonder if it I could do
> it again knowing it will not work. Hi Hi they have a mu of 37.
>  In one of the Radio Handbooks by Bill Orr, there is an example of a GG
> 304TL. It did require 200 Watts drive
> for 900 Watts output, but back then the tubes were very cheap.
>  But as far as the 833, I  see  no advantage of running them in GG due to
> the grid plate capacitance. Either a single or
> two in push pull would be better. I am not aware of any hams getting good
> results on 10 meters however. Some have been
> built for 80-20 meters but the output drops a bit on 20.
> 73
> Bill wa4lav
>
> ________________________________________
> From: Amps [amps-bounces at contesting.com] on behalf of Hsu
> [hsu4qro at gmail.com]
> Sent: Monday, January 26, 2015 5:44 AM
> To: Mike Waters
> Cc: amps at contesting.com
> Subject: Re: [Amps] 833A GG
>
> Hi  Mike, Thanks for your very good  and useful information.
>   Yes, you are right.I'll not think off this tube.
> 833C's manufacturer nearby  my home( 300 mtrs apart!)
> They made 3-500Z  too, in past two years, Almost all over the  world
> 3-500C
> from this manufacturer.There is a version of rugged 833C, anode diss. and
> filament current increase  30%-35% , they renamed it  FU-501
> http://hgdzg.com/a/english/Products/blg1/2014/0614/121.html,
>  There  is a more powerful triode  FU-605, same as Jananese 6T51
> ,http://hgdzg.com/a/english/Products/blg1/2014/0613/118.html
> the amplification facturer is 48,maybe it is suitable for GG ,its  anode
> diss is 800W.
> anode to filament  capacitance is 0.21p, maybe this tube is better?
>       73!Hsu
>
>
> -----原始邮件-----
> From: Mike Waters
> Sent: Monday, January 26, 2015 5:01 PM
> To: amps at contesting.com
> Subject: Re: [Amps] 833A GG
>
> Not recommended for GG on ANY band.. Not enough gain, for one thing; it
> would take several hundred watts of drive power to obtain the legal limit.
> Another issue is that the feedback capacitance is quite high.
>
> Some tube data sheets I've seen imply that it can be used above 10 meters.
> However, you'd almost certainly have to run two in P-P, beside using
> neutralization, not to mention careful attention to every last detail such
> as layout.
>
> Now, I do know of a guy that did build a working GG 833 amp, but it was a
> monoband (75m) amp. His 833 amp used a tuned input and required 600 watts
> of drive power, IIRC. But it could put out more than the legal limit, even
> by today's standards. I forget whether he used one or two tubes. I forget
> his call, but he used to hang out on 3895 in years past. The last I knew,
> he (Frank?) listens a lot on 3890 or 3892 at night.
>
> I built a homebrew legal limit amp using two 833Cs in parallel,
> swamped-grid-driven. I've used it successfully on 160, 80, and 40.
> However,
> it's kind of touchy on 40; the grid impedance drops too low there, for one
> thing (one sign that it needs neutralizing). It's kind of a work in
> progress, but it works perfect on 80 and 160. Future plans are to
> neutralize it with a tertiary winding in the broadband input matching
> transformer connected to the plates through a HV neut cap, and eventually
> see if it'll play on 20m.
>
> Details and photos of the 833C amp are on www.w0btu.com if you're
> interested.
>
> The graphite plate version of the 833A is actually an 833C, BTW.
>
> 73, Mike
> www.w0btu.com
>
> From: Hsu <hsu4qro at gmail.com>
>> To: <amps at contesting.com>
>>
>> Date: Mon, 26 Jan 2015 14:13:55 +0800
>>
> Subject: [Amps] 833A GG
>>
> Anyone have  experience  about 833 works on GG configurtion?Is it can work
>> 10 mtrs?I just contact with the manufacturer, the factory new tube
>> graphite
>> anode,only $50/ea, ,dirt cheap
>>    Hsu
>>
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