Passive Preamp Project vol. II

I've opened that topic before so that's why it's vol II since I have a few more questions to discuss.

Would that help if there will be a resistor or selectable resistor bank added to output of attenuator to bring the input impedance of the power amplifier to at least 10x level? Will that solve the problem of attenuation bandwidth that is not realy usable with low impedance poweramps (bellow 30k)?
If you know any links or literature please, advise.