Preamps from Supratek, Modwright, Dodd Audio and few others work wonders, however. Integrated amp might be the answer.
If you end up with extra funds, try external DAC with your source (not that there is anything wrong with it). That might also help out with overall sound characteristics/presentation. NOS DACs are usually thought as "musical" as opposed to sterile, hifi-ish sounding. Presentation of these DACs is usually warmer, a bit recessed, more analogue sounding but often compromised by lock of resolution and detail retrieval. Ofcause this is broad generalization and there are exceptions to this description.
If you can find manufacturer or dealer to provide a demo unit or offer in home trial, I'll say go for it and educate yourself with what's out there as far as digital reproduction is concern. Few ideas - RWA, Wyred, Lampizator DAC, Tranquility DAC (if you want to try USB audio done right) and few other that escape me at the moment. I believe all these brands offer in home trial.
And finally........
Good luck and have fun