Which DAC as a preamp?

I owned sources who has a pre amp inside. It worked well and there are more brands who use it. But.....when you use a pre amp, I have to admit that it is a lot more precise. Using a dac works, but to be honest it is not the best way to create the best.

10 years ago I bought a Pass Labs XP-20 pre amp. After that I used my Meridian 800Daxv4 with inbuild volume control for a pre amp for many years. 

By adding a good pre amp you will hear the benefit of it directly. The precision of a pre amp is bigger than you can imagine. It gives both voices and instruments much more a shape. Beside that it creates better dynamics as well compared ot a Dac with an inbuild pre amp/volume control.

You need to learn people and also let them hear the differences by using a real pre amp. When you did not hear/audition it in a comparison it is not possible to understand it. There is still a lot unknown in the world of audio.