Compatibility between preamp and amps

Good answer.

thanks but isnt there more to it than impedance ratios? like gain and sensitivity?

You've latched onto something of critical importance. So critical in fact that it applies not only to amp/pre-amp but to every component feeding a signal into any other component. From phono cartridge to phono stage to pre-amp, from CD to pre, from streamer, DAC, on and on. Critically important you study this to death until you understand it chapter and verse. 

Until one day you wind up just like me, so expert you haven't the foggiest what any of yours are. Because: I lied. Its just not all that.  

Lol SMH

With digital sources that output at higher voltages than most analog ones the 11 dB gain in the pre may be beneficial. You have 41dB of gain total which should  be fine. One thing I question is the amps sensitivity. At 0.85 volts, it is very sensitive if that is all it takes to drive the amp to full power. The sensitivity of the speakers also come into play.