[Amps] re: CTI screen regulator, tubes vs solid state

[Richard]

>The URL worked today, must have been a network problem.
>
>Look at this text........

I looked and I found a few glitches.  I made some minor improvements & or 
notes in the lines that begin with //.
------------------
>Triodes are Good, Tetrodes are Better.... 
//  Cathode-driven triodes (or tetrodes) have less gain than grid-driven 
tetrodes.
>Unlike triode amplifiers, the PLA800 uses tetrode tubes, which have a 
>control screen grid. 
//  The modifier "control" confuses the screen grid with the control grid.
>The screen grid not only adds to the 
>amplification factor of the tube, but also controls the electron flow 
>to the plate. 
// the term "plate" is archaic.  Tubes have a neg.-cathode and a 
pos.-anode.
>When voltage regulation is used for the screen grid and 
>with the plate overload circuit, as with the PLA800, plate and screen 
>currents are limited to their maximum value. As a result you will not 
>overdrive the PLA800 creating sideband distortion or splatter. 
>Increasing the drive power beyond 50 watts, does not increase the 
>power output. Because of this self-limiting feature, an ALC circuit 
>is not needed. The amplified audio, as in SSB service, is clear and 
>clean, void of sibilance and distortion. 
// the words "sibilance and" should be deleted from this sentence. /see 
below/
>xxxx
>
>What an unusual technical explanation about screen current limiting 
>and distortion!!!

* Indeed Mr. Rauch, indeed.  Sibilance is the high-frequency component of 
speech -- which is made by directing air over the teeth with one's 
tongue.  Void of sibilance, speech would sound like jibberish.  
[examples: soft-c, ch, sh, f, s, z]  "suffering succotash" contains s9 
sibilance. 
>
>The schematic shows a cathode driven PA with no tuned input and no 
>swamping resistance, just straight from the driver into the cathode.
>
*  Hardly good engineering.  I couldn't locate find the schematic.  What 
or where is the URL?
thanks

>A totally non-regulated control grid bias system without a control 
>grid current indicator.
>
* For Class AB1, regulated grid potential is of virtually zero value 
because the grid current is zero.  

>He uses the center tap of the HV transformer to supply screen 
>voltage, and that is a good system.
>
* Agreed
> ...

-  R. L. Measures, a.k.a. Rich..., 805.386.3734,AG6K, 
www.vcnet.com/measures.  
end