Phono volume low / max level adjustment?

[PetyMety]

Thanks!

I try to make it as clear as possible with my bad englisch:

Clearaudio 3,3mV Cart/ Settings 3,3mV = sweetspot volume level -5db
goldring 6,5mV Cart/ settings 6,5mV = sweetspot volume level +10db

So the higher voltage output cart is significant lower volume and i can not explain why