[Amps] drive power

[Steve Flood]

As I muddle through the understanding of amp design, there is a remaining topic that is confusing me - in regard to matching drive power to the exciter (in this case a modern 100w transceiver).

I understand that my 100-w tranceiver should be run at maximum output to the amp input.  Apparently, this requires a grounded-grid setup to accomodate the relatively high drive level.   Yet there seems to be many amps that are grid-driven that require very small amounts of drive power.  Are these amps not designed to be used modern transceivers?  Are they commonly driven by homebrew low-power exciters?

In my case I am trying to design a g-g 813 amp.  The only g-g information I have found is in the Orr handbook which says 25w drive - which I asume is pert tube.  Do I next assume that I need 4  813's match my transceivers 100w max ouput level?  With what have folks been driving all those homebrew 2x813 amps over the years?

I've been told I'm wasting a good pentode by using it in grounded-grid.  Yet the 813 specs say something like 0.2 watts of grid-drive power, which is obviously (?) not meant for modern transceivers. 

Steve, KK7UV