[AMPS] 4cx250* amp building plans

[2]

>
>Rich says:
>
>>/\  A grid dissipation rating of 2w max. is not good news for g-g 
>>operation.  With Class AB1 grid-driven operation, grid dissipation is 0w. 
>
>We usually think of g-g as being AB2 with triodes or triode connected
>tetrodes/pentodes. Does it have to be?

/\  no.  the Collins 30S-1 is AB1 cathode driven.  

> I've never 
>seen an AB1 grounded grid design, but is there any reason why one couldn't 
>drive
>something like a 4CX250 in g-g and 
>keep it in AB1? I'd expect normal screen and grid voltages, and lower gain
>caused by the NFB.
>
>Or is there something blindingly obvious here that I've missed? - apart  from 
the
>fact that if you're going to the trouble of 
>providing  screen and bias supplies, 

/\  screen and bias supplies are a 'piece of cake' for 4cx250s.

> passive grid has the advantage of not
>needing tuned input?
>
/\  except on higher freqs.  The fly in the ointment with g-g is the more 
critical tuned inputs.
>
cheers, Peter 

-  R. L. Measures, 805.386.3734, www.vcnet.com/measures.  
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