Local Negative Feedback Question NFB LNFB

[MarshallPlexi]

I'm curious to know something about local negative feedback.

In Dumbles you often see: --|0.047uf|--*--22M-- going from the plate to the grid of the triode. In the same amp you could also see:
--10M--*--|0.047uf|--*--10M--

What is the difference? The only thing I can think of is that you could use a lower voltage rating on the cap since the high voltage DC from the plate first has to go through a 10M resistor before it gets to the 0.047uF cap.

With that in mind wouldn't this work just as well as the first example?
--22M--*--|0.047uf|--

I've done a lot of searching on the interwebs but I've not found anything on it yet.

[pdf64]

There's (almost) no Vdc dropped across a plate to grid feedback resistor if the cap isn't leaky.
See http://www.aikenamps.com/index.php/desi ... amplifiers for factors affecting resistor value selection for inverting feedback single gain stages.