I have a sonnet Pasithea DAC with built in analog preamp that I prefer to run without either of the 2 preamps I had tried.
first was a Don Sachs model 2. While I really liked this preamp for it big spatial and full sound, I felt like I lost something in the micro details of the music.
second was a Halo Serene, which I.bought based on reviews saying that it was transparent and would not change the sound character. I didn’t find this accurate and I never did take to it.
BTW - The reason behind adding the preamp was for me to incorporate a turntable into the system. Otherwise I would have stayed without it.
However, With my prior DAC, the Rockna Wavelight, I will say that adding the Don sachs Pre was a substantially positive move. Much better with DS than without.
If I had to summarize this all, I’d say it very much depends on your particular gear and its all just a best guess until you try it and hear it for yourself.
Good luck