Hello pro's,

I don't want to over think this, but I just pulled the trigger on a power amp rated at 10k(RCA) 15k(XLR) input impedance. Problem is I don't know the output impedance of my pre/pro(Marantz av7705). I looked everywhere and even called Marantz. My gut tells me all is ok...or is it!  I know you should be within the 1/10 ratio. So, does it make much difference whether your 1/10 or 1/100 ratio?

If you know you should be within the 1/10 ratio, then congratulations, you have somehow managed to retain useless information I have long since forgotten. At my advanced age I can only dimly recall it seemed to matter once. Long ago. Maybe. Dunno. No. Yeah I am sure now. I did think it was important enough to think about. What I cannot for the life of me remember is how many years of it not actually mattering it took before I started to forget why I thought it ever mattered in the first place. Sorry. Did you say something about over thinking something?
Although the output impedances of the AV7705 appear to not be specified by the manufacturer, according to a post I found at another forum those numbers are 800 ohms (RCA), and 200 ohms per leg (XLR, which means 400 ohms for the XLR outputs per the usual way of defining balanced impedances).

Those are the kinds of numbers I would expect for this type of product. And given that it is solid state the output impedances are unlikely to rise significantly above those numbers in the deep bass region (as happens in the case of many tube-based preamps, which can result in rolloff and/or undesirable phase shifts at low frequencies when the load impedance is too low), or at any other audible frequency. So given the input impedances of the power amp you stated the bottom line is no problemo!

Enjoy! Regards,
-- Al
Thanks to both for the quick response! Much appreciated. Now, I just need a head shrink for the Audiophelia Nervosa I have... 
The 1:10 ratio does matter as you want to minimize voltage loss at the load input. With most amps/preamps on the market this isn’t an issue because they conform. But to claim this should be completely ignored or best forgotten is nonsense. Last year I was discussing with Keith Herron whether he felt the VTSP-360 would be a good match with my amp and the FIRST thing he wanted to know was the input impedance of my amp. Why would an audio component designer/manufacturer ask a question like that if it didn’t matter at all and was completely unimportant?