$1000 player or dac recommendation

I have searched through recent threads and didn't see this specific question, alathough I am sure it is out there. I am looking to update/upgrade my digital front end. I am currently using an older Rotel player as a transport and running it into an MSB Link Dac. The rest of my system is a Sonic Frontiers SFL-1 Sig preamp and an Classe 10 amp. Mostly Kimber and Cardas cables. I have a pair of North Creek Borealis speakers (8" Two-ways)supplemented with an M&K sub. So I know a lot of this gear is not state of the art by any stretch, but I am pleased with the amp and preamp. I think my front end is the weak link so I am looking for a way to add air/detail and warmth. I would be really interested in your input as to what may be some of the best buys out there to improve my digital front end. I would probably have a prejudice for something that included a vacuum tube design. Everything I have has been bought used so I am not opposed to buying a used player or dac. I would also like your input on whether my current player can still be used as a decent transport and I should look to improved dac versus buying a differnt all in one box. Thanks in advance for your input.