Seventh Circle Audio

hello I have not had much time to enjoy my new preamp before heading back to work. Here's a question on my mind:
I had initially thought the rotary switch set the initial level of gain - and then I should use trim knob to hit the precise levels. If I couldn't get proper level at the first click of the rotary switch, I should ratchet it one further and try the trim again.

Now I wonder if there's more to it than this - or if anyone can explain in simpler terms what's going on in the circuit?

thanks!

You've got the right idea. However, if you want to use the N72 as an effects box, you can always crank the gain to get distortion to taste and then back off on the level to keep your converters happy.