How to match preamp and power amp?


How to match them by looking at the preamp output impedance and the input impedance of the amp? Any magic numbers? I don't understand their relationship. Please help.
audiolui
So, my power amp specs indicate an input impedance of 100 kOhms, and an input sensitivity of 2.71 Vrms.  The amp has only XLR inputs on it.

Would I be correct to assume that most SS pre-amps would work well?  The pre-amp I'm researching indicates an XLR output impedance of <160Ω.  Thanks!
That input sensitivity of your amp is on the high side. Your preamp will have to put out 2.71 volts or more to run that amp at full power. BTW, what amp are you using with such a high input sensitivity?
The pre-amp specs I'm researching indicates:  XLR Maximum output level>22VRMS.
The power amp is a Krell FPB 400cx. 
Would I be correct to assume that most SS pre-amps would work well?

Nearly all preamps, whether tube-based or solid state, will have no problem driving 100K. And that would certainly apply to a solid state preamp having an output impedance as low as 160 ohms.

Regarding the sensitivity, the 2.71 volt figure most likely means 1.35 volts per leg (i.e., for each signal in the balanced signal pair), which is about average.

Regards,
-- Al
 
My Cary SLP98P is 800 ohms impedance output, the Pass Aleph 2 has 10 kohms input impedance, will this work. It’s seems so from what I have read?,  But there are more knowledgeable folks on this forum who can advise? 
I was considering a 4m run of Nordost Red Dawn RCA unbalanced interconnects, does this effect the equation? 
‘Thanks