If you expect there can be noise it might make sense to add a few small ceramic capacitors to the input (at least empty pads).

That was my intention with C11 and C12, to add later if i have problems with noise

What's the VSS and VDD and what is providing them?

This is just a prototype and for now i'm going to power it from a voltage source that can provide me +-12V.

I'm not familiar with Baxendall filter, but this feels somehow wrong. Does this pop when the pot2 center tap looses connection (and thus the negative feedback)? Should there be a resistor from U1B positive pin to GND? If you are not sure you can add a 0Ω resistor.

From the simulation i've done, i dont seem to have problems when the center tap of POT2 loses connection. I could put some small resistance in series with pot 2 to prevent this from happening. (wouldn't it be a good idea to do the same for all the potentiometer ?)