Do preamps have a material affect on high level sources?

Yes that's fine, good quality ones are lower than 100pF foot.
  
Only if you've crap interconnects with high capacitance and over 4mt, does so called "driving the cable" become an issue As I said it's something manufacturers of active preamps have hung onto just to do scaremongering tactics with. 

I went passive a year ago ( Luminous Audio Axiom II, Walker Mod, 3 in, 2 out, single ended ), and never looked back. Enjoy ! MrD.

"...thought up by active preamp makers to aid in their product sales."

Funny to hear this from someone who floods these threads constantly pushing his own passive preamps. Just stick with technical inputs and leave out the editorials.

Only when going direct isn’t possible without "bit stripping" or if the source has no volume control, are passive pre’s the next best in line for transparency and dynamics, and yes that includes my one sunshine.

And not once did I mentioned mine in this thread or the last few months of threads, until you bring it up, and for that I thank you, for doing that and giving me some advertising, one could almost say you were shilling for the Lightspeed Attenuator, keep up the good work sunshine.

Forest and trees, if you can see them.

george, fair point. I should have said "pushing passive preamps" instead of "pushing his own passive preamps". But in your case that makes no difference. Either way, your remark to Ralph was completely unnecessary.