[Boatanchors] 813 grid to filament short

[rbethman]

On 10/1/2015 7:33 PM, Paul Baldock wrote:
> At 01:37 PM 10/1/2015, you wrote:
>
>> The entirety gets back to 813s and mounting them horizontally. Bad 
>> move!  W3BYM uses 4 813s to modulate 4 813s.  Should one dig up the 
>> old ER issue, you'll find that he mounted them vertically! The only 
>> _intelligent_ way to do so.
>
> Well I'm an intelligent person, I think. At least intelligent enough 
> to read the manufacturers data sheet that says " in a horizontal 
> position, the base pins No2 and No6 should be positioned vertically 
> one above the other"
>
> Then of course there's those beautifully constructed 813 amps in the 
> 1968 ARRL handbook 
> http://www.arrl.org/files/file/protected/Group/Members/Technology/tis/info/pdf/68hb195.pdf 
> . Yes the tubes are on their side, and that seems like a quite an 
> intelligent article also.
>
> - Paul
The manual that you read regarding the 813s simply states "IF" you are 
going to mount them horizontally, to mount it in that fashion.

Does this same manual say that the filament will NOT sag and short out?

The manuals on 572Bs read essentially the same way.

The last I've seen, no manual states that the filament won't sag, nor 
that it won't short to the grid.

Engineers also designed the Chevy Vega.  It took Cosworth to make it a 
viable dependable vehicle.

I mentioned W3BYM and his home-brewed 813s modulating 813s.  It would be 
an additional comment to add that he was also a satellite engineer.  The 
same for the late WC3K.

Neither of them has/had significant failures while working for Comsat, 
nor the projects they took on in their shacks.

I look at the entirety, and then I look at what stays up and running, 
versus what develops failures.

Personally, I do believe that this methodology is indeed intelligent.

My 813 GG amp never had a single issue.  The tubes were mounted 
vertically.  They also had a blower running over them, and their sockets 
were mounted below the chassis to allow air to flow upwards from below.

Different strokes for different folks.  I have yet to have a final PA of 
mine ever blow.

Then again I never have tried using sweep tubes for finals.

Regards, Bob - N0DGN