[AMPS] Switches

[measures]

>
>> I wouldn't say that the screen supply in the 91/99B is well regulated
>> (only zeners) so that amp doesn't necessarily show us the best IMD
>> performance the 4CX800 is capable of.
>
>Many amps have less regulation than that Ian!
>
>My point is that by the time you build a good system that rivals GG 
>triodes for IMD, it costs more money that the triode amp.
>
Reasons for using a tetrode in grid-driven configuration is:
1.  a power gain of up to 200 vs. the triode's gain of c. 15. 
2.  The AB1 neutralized  grid circuit (variable-L resonant with grid-C) 
is a Natural for general coverage.  However, achieving general coverage 
with a G-G triode is not easy.  Maintaining a tuned input Q of approx.  
two over 9 bands is difficult.  

>Unless you add negative feedback in the cathode of the tetrode and 
>use a well-regulated supply, they aren't so clean.  
> 
>> Even so, I think it's being far too sweeping to imply that all tetrodes
>> have worse IMD performance than (all) triodes. There are far too many
>> other factors in the design and operation of an amplifier.
>
>Of course. Some tetrodes are very clean, but then are some 
>triodes. 
> 
Many Tetrode amps are typically cleaner than transceivers.  Also, Eimac's 
IMD specs are 4x better than they appear.  

>> There's no doubt that tetrode amps are much less "plug-and-play" than
>> triodes. It's easier to get things wrong, either at the design stage or in
>> operation. But if you do get everything right, a tetrode can give good IMD
>> performance.
>
>The key is "getting everything right". Many hams can't tune a GG 
>triode properly, I'd hate to see what they sound like with the screen 
>in current limiting!

Assuming that hams are not capable of adjusting  the load-C for a 
specified  screen-current, is a load of Bandini.  Is Mr. Rauch on some 
kind of superiority trip or what?
>

>> >you still haven't solved the bandswitch problem.
>> >
>> Which all tube amps share alike.
>
>Exactly. That problem remains the same.
>
Multronics make a line of suitable insuuctors.  Jennings makes a line of 
suitable capacitors.  With  9-bands, general coverage makes more sense 
than a bandswitch.    

end

-  Rich..., 805.386.3734, www.vcnet.com/measures.  
end


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