Your bottleneck is the LS15 not the cd player. I have the same speakers as you, and had an LS15, so I have real world experience. The LS15 would be more at home with a small Proac or other monitor. It is sorely lacking on a full range speaker like the N802.
Tube/SS synergy?
I have a new system: Cary 306/200 cdp and Audio Research LS15 pre-amp. BWN802 speakers. Overall good quality, a nice improvement in bass response, sound staging. Can't help wondering how substituting an Audio Research CDP or something else would effect sound. My old system was matching Classe gear and the synergy was quite remarkable. any one care to share their thoughts/experience?