I've struggled to understand this thing with gain matching. It doesnt't seem very intuitive to me. The chief engineer at B&O, Geoff Martin, recently had an excellent blog post about it though:
http://www.tonmeister.ca/wordpress/2017/02/13/signal-levels-and-dynamic-range/
That post clarified a couple of things to me, even though I'm not sure if I really understand it yet. His main rule of thumb is to have as much gain as possible in the beginning of the chain.
My future chain of command will probably look like this:
Oppo 105 --> DBX driverack PA2 (crossover duties and eq) --> hypex amps --> speakers
The reason for the PA2 is that that's the crossover box that is used by the manufacturer of the loudspeaker I'll probably end up buying. The hypex amps have a set gain of 26 db. I will therefore probably have to turn down the digital volume control in the Oppo quite a bit, since my listening levels are moderate (usually 68-75 db as baseline), and the drivers of my future speakers have a sensitivity of 86 (woofers) and 90 db (tweeter).
Is this not an ideal gain match, for example? Would I be better off running the speakers with amps with adjustable gain or a lower set gain?
EDIT: Perhaps this amp for example -
http://www.classdaudio.com/4-channel-amplifiers/4-channel-sds-450c-audio-power-amplifier/