Later, you might wish to try learning about the opamps/active filters more, with an eye towards being able to tailor a gain stage to have the desired EQ characteristics the HF needs for being flat. Can also add a stage with low end eq for the bass.

For example, in my preamp, there is a "+6 dB at 50 Hz." contour circuit...all it is, is a cap and resistor in front of a gain stage. There is even a bread board type kit out now, to learn and play with these things. And web resources. Depends on how far down the road in this hobby you wish to travel.

Sounds like you already have your system pretty well sorted out for now. Sam