[AMPS] Tetrode Output

[Bob Marston]

Hi Rich and List

Here is one I can sink my teeth into. Rich some of your comments regard the
Grid Driven Tetrode design lead to some confusion on my part. Let me
reference your specific comments

> Indeed.  If a screen bypass C shorts, ground the screen, connect the
> screen supply pos.. to chassis gnd and the neg. to the cathode.  For
> tetrodes with handles, this is SOP. There's a grounded screen config.
> schematic on my Web Site using the requisite screen shunt regulator. .

First off I assume the schematic you are referring to is the one labelled
Figure 5 (Class AB1 grid input circuit) on your web page.

2) Now if the screen is shorted by the bypass cap it is at RF Ground but
still is floating at DC....RIGHT?

3) Your schematic does not show the pos. screen supply with a ground symbol
Earth or Chassis. Is this an omission or am I missing something?

4) Take these 2 points together if the screen is grounded and the pos.
screen supply voltage is at chassis ground how does the screen current
meter work?

5) In a slightly different vain what you are suggesting is rather than
elevate the screen above ground potential you recommend lowering the
cathode below ground. Am I right?

6) Does one have to take an special precautions with the filament
transformer as it's secondary will be hundreds of volts below ground?

7) Will this affect the bias voltage of the control grid? Should the
voltage potential of the all the tube elements remain the same wrt each
other and ground potential?

8) You state that this practice is SOP for tetrodes with handles. How so,
one would think that 5 to 10 KV bypass caps would be alot less trouble.
What's the rationale?

9) Implicit in this design is the need to allow the Plate supply return
line to float. Am I right?

73s

Bob



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