[Amps] Grounded Screen 4CX1500B

[R.Measures]

On Nov 7, 2005, at 11:43 PM, Ian White G/GM3SEK wrote:

> Shawn Tayler wrote:
>>
>> I had totally missed that.  The input circuits were right next to the
>> grid circuit and I had simply assumed.  Well how about that.  Hmmm,
>> very interesting.  Kinda burst the bubble for me.  I must be blind and
>> deaf.....
>>
> The problem is that everything about the 30S-1 is more weird than you
> think it's going to be.

Amen, Ian.  However, the 30S-1 is the only amplifier that is apparently 
parasite-free.  This may have something to do with the fact that its a 
G-G amplifier with Two RF-grounded grids shielding the input from the 
output.
>
> It's a fascinating design, full of complexities caused by the decision
> to cathode-drive a tetrode. You have to wonder why they didn't use
> grid-driven, passive grid - or hadn't that been invented at the time?

Collins engineer Vern Baumgartner, W6HW, told me that Art Collins 
wanted a SSB linear that would not be driven to more than 1000w by the 
S-Line.  A tetrode in AB1, cathode-driven was one solution.
>
> -- 
> 73 from Ian G/GM3SEK
> http://www.ifwtech.co.uk/g3sek
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Richard L. Measures, AG6K, 805.386.3734.  www.somis.org