Replaceing Preamp

I need to replace a now inoperable B@K preamp processor.
I thinking of replacing with a two channel tube preamp and down the road possibly upgrading my present amp. Any input along these lines would be appreciated. My current system follows. Speakers vandersteen 2cs byamped to rotel RB 981 along with Vandersteen 2wq sub music Fidelity Tri Vista Dac.

The Rotel amp has low input impedance and I understand that certain requirements have to be met to incorporate a tube preamp.
Iam trying to warm up the sound from my current setup!

Thanks:

Gary