[Amps] Re: triode-connected tetrodes

[skipp s isaham]

Hi Don,
-
One of the best written explanations I've seen is in the Green 
Cover W6SAI Radio Handbook, 18th Edition.  
-
Certain tetrode/pentode tube geometries have potential 
problems when placed in grounded grid layouts.  
Excessive grid currents and drive division are the issues.  
-
Some handbooks drop the ball on the subject, some just 
mention it in passing which include other editions of the 
same "SAI" Radio Handbook. 
-
Certain tetrodes and pentodes with less "hardy grid" 
construction fail in g-grid operation when driven hard. 
-
The 4-400 and 4-1000 are tubes which by nature are not 
best operated g-grid, but because of sturdy construction 
do hold up well.  Linearity comparisons are a whole 
separate topic. 
Other less forgiving tubes like the 4cx1000 and 5cx1500 
quickly go on permanent vacation when abused, based 
on a more fragile grid construction/geometry.
- 
I have some data on certain tubes in certain layouts 
of which I'll be happy to share. If you can't find the Green 
SAI handbook, I can find a photocopier with enough 
notice. 
- 
skipp
-
http://sonic.ucdavis.edu    has some tube data on the 
Amateur Radio Page. 
-
On Fri, 21 Feb 2003 15:54:55 -0500 "Don Belcher" <dbelcher at wherenet.com>
writes:
> I saw some emails on grounded grid triode connected tetrodes, such as 
> the 4-400.  I can find very little on this...Do you have any data?  
> Can you refer me to someone who does?
> 
> thanks and 73
> Don
> W4JVE
> dbelcher at wherenet.com
> 


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