+1 on the Rotel RC-1590 preamp has a good built-in DAC.
You also should sell your RB-1080 power amp and get the current model RB-1582 Mk2 power amp or the RB-1590 power amp. The RB-1582 Mk2 is a replacement of the RB-1080. The RB-1582 Mk2 sounded quite a bit better than the RB-1080, much more refined smoother highs much richer warmer and much lower noise floor than the RB-1080. Tonally the RB-1582 Mk2 is on the warm side whereas the RB-1080 is on the cool side of neutral. The RB-1582 Mk2 exhibits much richer much more density in mid-range mid-bass upper bass and bass regions than the RB-1080.
The RB-1590 amp is even better than the RB-1582 Mk2 and has lots more power too and sounded more resolving with better separations etc.