It should be 0db. If not, then you can back off those amp gains even farther and reduce the noise even more.

I do sometimes listen to some of my quieter albums at 0db, so I don't think I want the gains any lower. But it's not really a problem at all, the noise it only audible if you press your ear against the speaker grill and it's kinda hard to do that while driving.

Borislav