[Amps] AMPS

[Joe Subich, W4TV]

Rich writes: 

> > Unless Rich can provide a specific example of some other amplifier
> > control circuit that does contain such a transistor, we may have to
> > conclude that no such circuit actually exists.
> 
> As I recall, one model of Alpha 3, 8874 amps used a pass transistor  
> to interrupt the flow of dangerously high  grid current

Not likely ... Alpha did not use grid trips in any of the '76 or '78 
series amplifiers.  I believe they converted to the 3CX800 in the 86 
and 89 amplifiers.  I know that all of the 8874 amplifiers tied the 
tube grids directly to ground and did not include any grid current 
trip ... even the 86 with electronic bias switching.  The only active 
components were electronic bias switching and QSK boards - none of 
which "opened the grids."  

However, since W0UN, AAA0RS and W0ID no longer contribute regularly 
to this forum - schematics for the 76 and 86 amplifiers are on BAMA 
if you care to check the facts before you make wild (wrong) statements. 

> > I already posted the shorter version yesterday. The longer 
> > version (which is easier to understand because it includes 
> > diagrams) is in the downloadable user manual for the Triode 
> > Board. Here is a direct link:
> > http://www.ifwtech.co.uk/g3sek/boards/triode/triode-manual.pdf
>
> What is the URL of your schematic, Ian?

Ian just gave you the URL of the schematic - it's on pages 30 and 
31 of the manual.  The manual includes an extensive, well written 
discussion of tube protection, how it works and how to configure 
it.  However, since it does not agree with your pseudo science you 
don't acknowledge it - as usual. 

73, 

   ... Joe, W4TV