I'm going to be playing with high level modulating a http://www.rfparts.com/pdf_docs/SAV/SAV17.pdf
The question is I've seen some circuits that modulate the driver stage along with the last stage?
Any reason for doing that?
This may not work well trying to modulate the collector as in a class C amplifier. I believe that is what you are talking about doing. The conduction angle may be too great (not far enough into class C) to modulate properly.
The modulated amplifier must be operating non linear in order to modulate it. If it is operating in a linear mode it will not modulate.
Sometimes in tube transmitters the driver stage is modulated a small amount along with the output stage. Some tubes do not plate modulate as well as others and adding modulation to the driver stage helps achieve full modulation.
This chip looks as though it is intended as an amplifier for FM signals and you may not be able to control the drive properly in order to properly modulate it.