[Amps] 833A GG

Mon Jan 26 17:13:55 EST 2015

That’s worth more to a collector than chancing it is gassy and blow the 
filament.

Carl
KM1H

--------------------------------------------------
From: "Fuqua, Bill L" <wlfuqu00 at uky.edu>
Sent: Monday, January 26, 2015 4:10 PM
To: "Carl" <km1h at jeremy.qozzy.com>; "Hsu" <hsu4qro at gmail.com>; "Mike Waters" 
<mikewate at gmail.com>
Cc: <amps at contesting.com>
Subject: RE: [Amps] 833A GG

>  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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