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Re: [Amps] Horizontal or verticle?

To: "AMPS" <>
Subject: Re: [Amps] Horizontal or verticle?
Date: Mon, 26 Jan 2004 16:46:05 +0200
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It is hard to give you the right final answer.
In the Russian military power amplifier BRIG (8 x GU-74B) all tubes are in 
horizontal position. And it works without any problems. And number of hams 
using it in the shacks. The only problem is that you can have around 1500W 
output power and PA will consump about 7500W from the power line. Monkey 
I think it could be because tubes working not  hard and in order with all 
pasport data. As I know anod voltage is only 1200V. And tubes working in 4 
+ 4 system, in distribute amplification mode (not sure I'm right with this 
technical term, sorry for my bad English).
But if you would like to use them in hard operation conditions - better to 
use those tubes in the vertical position. Distances between inner parts 
are small and if you will pump the tube on maximum ranges the grids in 
horizontal tube could overhang (or deform)...  and you can imagine the 
final possibilities.

Sorry ones again for my bad English.

73, Remi LY2MW

>There is a bit of debate between Polish and Ukrainian amp builders.
>The some members of the Polish school argue, based on some American 
>literature, that a valve (ceramic) should be based vertically, while some 

>well known Ukrainian builders, have there GU74b's amps horizontal.
>Now some Poles maintian horizontal is bad as, as for lack of a better 
>word, "pollutants" which occasionally fall from the anode land on th 
>rahter than at the base of the valve as would be the case if the valve 
>verticle, and this eventually causes a short in the valve.

**  I would go with base down.  I have seen many 8877s/3cx800A7s-et 
cetera with gold-sputtering 'pollution' that were still usuable if the 
gold meltballs could be safely parked in the base. 
>My feeling is that rather the cooling problem is the issue here, but I 
>wonder s the valves were designed with the though in mind of working in 
>any positon.
>Any comments

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