@phill55 Generally speaking, if you are wanting to mix tubes and solid state, the consensus is that you are better off with a tube preamp (including line section) and then a solid state preamp.
If the front end of your system is imparting a coloration or losing detail, there is no way to correct for it downstream. Solid state colorations tend to be brightness and a harder top end; this is caused by a variety of factors related to distortion, although overall solid state tends to have less distortion than tubes.
The problem is the ear converts all forms of distortion into tonality (hence the brightness) but the ear also has a masking principle. The lower ordered harmonics (2nd, 3rd and 4th) tend to mask the presence of the higher orders (which contribute to brightness and hardness) and this is why tubes sound smoother, because the higher orders are masked. What is not well understood is why the lower orders can contribute to soundstage depth and detail which causes circuits with them to sound more neutral; this is an area which I think needs more research.
