Which PreAmp for Marantz PM KI Ruby

Looking over your system you would not gain much from just adding a preamp to your chain. To upgrade from the Ruby, you would need to move to new separates and that will not be cheap. So that leaves your loudspeakers as the best route to improve your system. Have you thought about some full range towers? 

Preamps are mostly for switching. No telling if you have any purpose.

As a buffer they can improve sound. Or not.

Preamps are mostly for switching.

...and providing the amp the signal, level, and impedance they are looking for. 

Interesting. The reason I considered the upgrade was that when I played around with the RME as pre amp, I noticed a considerable difference in sound quality, mainly soundstage and imaging improved (to my shock). There’s a chance that it may not be an improvement to some people, but can’t deny the fact that there was an audible difference.

@russ69 in addition to space constraints (NYC apartment), I’ve always liked the tightness of a bookshelf. I also have to admit that I compared towers in the same price range or less as the dynaudio bookshelf’s I own. Any speaker recommendations that will share good chemistry with the rest of the gear (assuming i keep the electronics)?  

Any speaker recommendations that will share good chemistry with the rest of the gear (assuming i keep the electronics)?  

Triangle Signature Thedas, maybe? Probably any of the next level bookshelf loudspeaker.