Volume control vs. attenuation control

It's highly advantageous to play around with both controls in order to match amp and pre. I would consider myself lucky to have such ability. You want enough gain in each to optimize sound quality and not too much as to cause distortion. And you want pre to have enough in relationship to amp's sensitivity but not so much as to overdrive the amp causing undue distortion. Hopefully other members will give a more technical explanation, but optimum settings will be dependent on speakers (and source). Will be dependent on how demanding are the speakers.

All volume controls are attenuators. Gain stages amplify the electrical signal and attenuators, either before or after a gain stage, reduce the level of the signal.

The setup up Markpao describes will allow him to play with both attenuators to achieve the combination of lowest signal to noise ratio and flexible volume control settings.